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The widespread use of antibiotics in pharmaceuticals and aquaculture has led to their high concentration in wastewater, posing threats to ecological stability and human health. In addressing these challenges, in our preliminary work, the embedding of microbial electrodes in a microbial electrochemical system (MES) demonstrated effective degradation of the antibiotic sulfamethoxazole (SMX) in aquatic environments. However, challenges persist, including low electron utilization efficiency and suboptimal antibiotic degradation rates. This study introduces the modification of microbial electrodes with the bimetallic oxide MnCo2O4 to enhance the electrochemical performance of the MES and the degradation efficiency of SMX. Electrochemical analysis revealed a reduction in system internal resistance by 18.99% following electrode modification. The specific capacitance of the microbial electrodes increased from 232.47 to 483.47 F/g. During operation, the MnCo2O4 -modified electrodes exhibited a 12.41% increase in average SMX degradation efficiency compared to unmodified electrodes. Microbial community structure and correlation analysis indicated a significant rise in the richness and diversity of microbes on the modified electrodes. SMX-degrading bacteria such as Acetobacterium and Trichococcus were notably enriched. This research demonstrates the effectiveness of material-modified electrodes in enhancing electron utilization in microbial electrochemistry, while also offering insights into sustainable bioremediation strategies for surface water. [ABSTRACT FROM AUTHOR]

The appropriate volume of filtered water samples is crucial for accurately reflecting microbial community characteristics. Previous research has shown that changes in water sample volumes significantly affect bacterial diversity and the relative abundance of dominant taxa in marine environments. However, the specific impact on freshwater microbial diversity and community structure, particularly for eukaryotic microorganisms, remains unclear. To address this gap, we collected water samples from eutrophic Lake Taihu and mesotrophic Lake Bosten. We filtered the samples through 0.2 μm filters using volumes ranging from 0.1 to 2 L for Lake Taihu and 0.1 to 3.2 L for Lake Bosten. Analysis of 18S rRNA gene amplicons revealed that variations in filtered water sample volume significantly affected the diversity, community structure, and composition of eukaryotic microorganisms. In light of these findings, we recommend using a filtered water sample volume of approximately 0.2 L for eutrophic aquatic ecosystems and 0.8 L for mesotrophic aquatic ecosystems in microbial analyses. These recommendations underscore the importance of selecting the appropriate filtered water sample volume to ensure representative and reliable results in the study of eukaryotic microorganisms in freshwater ecosystems. KEY POLICY HIGHLIGHTS: Impact of Filtered Water Volume on Microbial Analysis: The study highlights the significant influence of filtered water sample volumes on the analysis of eukaryotic microbial diversity, community composition, and species representation in freshwater ecosystems, emphasizing the need for careful volume selection in microbial studies. Optimal Filtration Volumes Identified: Specific recommendations for filtered water sample volumes are provided, with 0.2 L suggested for eutrophic ecosystems like Lake Taihu and 0.8 L for mesotrophic ecosystems like Lake Bosten, ensuring accurate and reliable representation of microbial communities. Differential Effects in Eutrophic and Mesotrophic Ecosystems: The research demonstrates that eutrophic and mesotrophic ecosystems require different filtration volumes to capture microbial diversity accurately, with eutrophic systems needing smaller volumes to avoid a decline in diversity indices and mesotrophic systems requiring larger volumes to maximize diversity and richness. [ABSTRACT FROM AUTHOR]

[Display omitted] • Successful and stable high-solid digestion was achieved in both CSTRs and PFRs. • Reduction of volatile solids was 50–54% in both reactor types. • Biogas and methane yields were significantly higher from PFRs than CSTRs. • Bacterial population was dominated by Defluviitoga in PFRs and MBA03 in CSTRs. • Stirring frequency was the likely cause for difference in microbial community. High-solid digestion (HSD) for biogas production is a resource-efficient and sustainable method to treat organic wastes with high total solids content and obtain renewable energy and an organic fertiliser, using a lower dilution rate than in the more common wet digestion process. This study examined the effect of reactor type on the performance of an HSD process, comparing plug-flow (PFR) type reactors developed for continuous HSD processes, and completely stirred-tank reactors (CSTRs) commonly used for wet digestion. The HSD process was operated in thermophilic conditions (52 °C), with a mixture of household waste, garden waste and agricultural residues (total solids content 27–28 %). The PFRs showed slightly better performance, with higher specific methane production and nitrogen mineralisation than the CSTRs, while the reduction of volatile solids was the same in both reactor types. Results from 16S rRNA gene sequencing showed a significant difference in the microbial population, potentially related to large differences in stirring speed between the reactor types (1 rpm in PFRs and 70–150 rpm in CSTRs, respectively). The bacterial community was dominated by the genus Defluviitoga in the PFRs and order MBA03 in the CSTRs. For the archaeal community, there was a predominance of the genus Methanoculleus in the PFRs, and of the genera Methanosarcina and Methanothermobacter in the CSTRs. Despite these shifts in microbiology, the results showed that stable digestion of substrates with high total solids content can be achieved in both reactor types, indicating flexibility in the choice of technique for HSD processes. [ABSTRACT FROM AUTHOR]

Biological methods do not effectively remove pharmaceutical products (PPs) and antibiotic resistance genes (ARGs) from wastewater at low temperatures, leading to environmental pollution. Therefore, anaerobic–aerobic-coupled upflow bioelectrochemical reactors (AO-UBERs) were designed to improve the removal of PPs at low temperatures (10 ± 2 °C). The result shows that diclofenac (DIC) and ibuprofen (IBU) removals in the system with aerobic anodic and anaerobic cathodic chambers were 91.7% and 94.7%, higher than that in the control system (12.2 ± 1.5%, 36.5 ± 5.9%), and aerobic zone favors DIC and IBU removal; fluoroquinolone antibiotics (FQs) removals in the system with aerobic cathodic and anaerobic anodic chambers were 17.5–22.4% higher than that in the control system (9.1–22.4%), and anaerobic zone favors FQs removal. Analysis of microbial community structure and ARGs showed that different electrotrophic microbes (Flavobacterium, Acinetobacter, and Delftia) with cold-resistant ability to degrade PPs were enriched in different electrode combinations, and the aerobic cathodic chambers could remove certain ARGs. These results showed that AO-UBERs under intermittent electrical stimulation mode are an alternative method for the effective removal of PPs and ARGs at low temperatures. [ABSTRACT FROM AUTHOR]

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Global concern revolves around the persistent attributes of harmful non-biodegradable contaminants, especially heavy metals and metalloids, which draws attention to environmental pollution. As regards to soil ecosystem, microorganisms have a significant impact on heavy metal concentrations, either actively or passively. Heavy metal toxicity profoundly impacts the metabolic activities of microbial communities, leading to disruptions in essential cellular processes. Heavy metals interfere with the enzymatic reactions necessary for energy of metabolism, nutrient cycling, and organic matter degradation, resulting in reduced microbial growth and activity. The Biolog Ecoplate method is used as an effective tool for assessing microbial activity. The potential use of Biolog Ecoplate in the study of microbial community structure and diversity in heavy metal -polluted soil was investigated. In order to achieve this goal, multiple keywords combinations were used to filter the most important results in the field. In metal-contaminated soils, the use of Biolog Ecoplate has led to notable changes in microbial community composition, marked by increased populations of resistant and metal -reducing microorganisms. [ABSTRACT FROM AUTHOR]

Thise study investigated the effect of three lignocellulolytic thermophilic Bacillus strains (F11, Q1, and FP4) on lignocellulose degradation, enzymatic activities, and microbial community structure in composting. The lignin degradation rate reached 36% in the presence of the inoculant, the hemicellulose degradation rate ranged from 43% (F11) to 51% (Q1), and cellulose degradation rates reached 57% in F11 and in FP4, which were significantly higher than the control (CK). The inoculation treatment could explain 28% of the lignin degradation for all three strains. The contribution of FP4 to hemicellulose and cellulose degradation was 30% and 20%, respectively. Compared to CK, lignin peroxidase activity in the water extract of the compost had increased by 66~145% for inoculation treatments, and manganese peroxidase and laccase activity increased by 114% and 78% for Q1. The inoculation stimulated the growth of indigenous bacteria with stronger lignocellulolytic enzyme-producing ability; such shifts in microbial communities were most likely responsible for the improved lignocellulose degradation. [ABSTRACT FROM AUTHOR]

Most research on plant–microbe interactions emphasize the effects of micronutrients on the rhizosphere microbial community structure. However, the influence of seed structures, particularly the radicle sheath, on microbial diversity at the seedling root tips under varying temperatures and humidity has been less explored. This study conducted controlled indoor experiments in the northern desert of Xinjiang to assess the radicle sheath's impact on microbial community composition, diversity, and function. The results indicated no significant changes in the Chao1 index for bacteria and fungi, but notable differences were observed in the Shannon and Simpson indices (p < 0.05). Under drought conditions, the radicle sheath significantly reduced bacterial infections without affecting fungi. Genus-level analysis showed an increased abundance of specific dominant bacterial groups when the radicle sheath was retained. NMDS analysis confirmed its significant effect on both bacterial and fungal community structures. LEfSe analysis identified 34 bacterial and 15 fungal biomarkers, highlighting the treatment's impacts on microbial taxonomic composition. Functional predictions using PICRUSt 2 revealed that the radicle sheath facilitated the conversion of CH4 to CH3OH and various nitrogen cycle processes under drought. Overall, the radicle sheath plays a crucial role in maintaining rhizosphere microbial community stability and enhancing the functions of both bacteria and fungi under drought conditions. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) pollution in soil has become a huge problem for agricultural production in China and even the world. Passivation and phytoremediation are two important remediation technologies for Cd pollution. In this study, the cadmium-contaminated and phosphorus-poor farmland soil around a mining area in Huainan was taken as the research object, and the remediation effect of biochar and phosphorus-containing materials on soil cadmium pollution was discussed. The results showed that the combined application of biochar and phosphorus-containing materials significantly reduced the pH of non-rhizosphere soil and rhizosphere soil, and increased the content of soil dissolved organic carbon (DOC). The combined application of biochar and phosphorus-containing materials significantly reduced soil pore water Cd and soil available Cd. In addition, both a single application of biochar and synergistic application of biochar and phosphorus-containing materials significantly increased the biomass of aboveground and underground parts of amaranth and soil urease and catalase activities. Phosphorus application reduced the bioavailability of Cd in soil. With the increase in phosphorus application, the content of available Cd in soil decreased significantly, and there was a certain negative correlation between Cd content and phosphorus content in plants. The abundance of beneficial microorganisms such as Ochrobactrum, Anaerolinea, Achromobacter, and Cellvibrio in soil was significantly increased after the synergistic application of biochar and phosphorus-containing materials. [ABSTRACT FROM AUTHOR]

Saccharomyces cerevisiae can metabolize sugars to produce ethanol and secondary metabolites that contribute to the complex flavor profile of Baijiu, a traditional Chinese distilled beverage. The yeasts that contribute to Baijiu fermentation are mostly adventitious strains that show low ethanol production and stress resistance, which results in lower Baijiu yields and quality. Here, we screened S. cerevisiae strains for ethanol production and stress resistance. The best selected strain, SW4, produced a final ethanol titer of 148.1 g/L, which was 113.8% higher than the initial 69.6 g/L. Additionally, the solid-state fermentation of Baijiu with the addition of S. cerevisiae SW4 (QH) resulted in a significant increase in the relative abundance of Pediococcus and Saccharomyces at days 0–14 compared to the control (KB), which may be the main reason for the alteration of Baijiu flavor. Analysis of flavor compounds revealed that QH increased the concentration of alcohols by 44.82% relative to KB after 7 days of fermentation, as well as increasing the concentration of alcohols and esters by 13.06% and 7.11% after 28 days of fermentation. Measurement of 15 differential flavor compounds revealed that 8 were positively correlated with Saccharomyces (p ≤ 0.05), all of which are important flavor compounds contributing to the quality to Baijiu. The Baijiu yield of QH was 25.18%, which was 11.47% higher than that of KB. Overall, this study confirms the positive effects of exogenously added S. cerevisiae on the microbial community structure and flavor of Baijiu at different stages of solid-state fermentation, providing novel opportunities for improving the yield and quality of this important traditional beverage. [ABSTRACT FROM AUTHOR]

The crude metabolic extract from plant biocontrol bacteria plays a very important role in sustainable agricultural production. These extracts help maintain healthy plants and have very important application prospects in biotechnology related to alleviating apple replant disease (ARD). In this study, Bacillus velezensis XC1 (T1), Bacillus amyloliquefaciens QSB-6 (T2), and Lactobacillus reuteri LBR (T3) were examined to characterize the ability of their crude metabolic extracts to alleviate ARD. The high-throughput sequencing data of the soil microbial community structure were analyzed in relation to LBR crude metabolic extracts, and an extensive untargeted metabolomic analysis of UHPLC-Qex active components was performed. Active LC-MS/MS revealed that the main secondary metabolites involved in the biological control exerted by L. reuteri included 3-hydroxypropionaldehyde, extracellular polysaccharides (EPS), p-hydroxybenzoic acid, and azelaic acid. These crude metabolic extracts significantly inhibited the growth of soil pathogenic fungi, reduced the abundance of Fusarium, promoted the abundance of beneficial bacteria such as Pseudomonas, and optimized the soil microbial community structure. Improved modern extraction and purification technologies will be able to offer additional insights into the mechanism of action of these secondary metabolites and enable them to be used in biological preparations to prevent and control ARD in the future, as well as to allow harmful chemical fumigants to be discontinued. [ABSTRACT FROM AUTHOR]

As one of the most important fertilizers in agriculture, the fate of urea-derived nitrogen (urea-N) in agricultural ecosystems has been well documented. However, little is known about the function of urea-derived carbon (urea-C) in soil ecosystems, especially which soil microorganisms benefit most from the supply of urea-C and whether the utilization of urea-C by the rhizosphere and bulk soil microorganisms is affected by irrigation regimes. To address this, a soil pot experiment was conducted using 13C-labeled urea to investigate changes in the composition of the rhizosphere and bulk soil microbial communities and differences in the incorporation of urea-derived C into the rhizosphere and bulk soil phospholipid fatty acids (PLFA) pool under flooded irrigation (FI) and water-saving irrigation (CI). Our results suggest that the size and structure of the rhizosphere and bulk soil microbial communities were strongly influenced by the irrigation regime. The CI treatment significantly increased the total amount of PLFA in both the rhizosphere and bulk soil compared to the FI treatment, but it only significantly affected the abundance of Gram-positive bacteria (G+) in the bulk soil. In contrast, shifts in the microbial community structure induced by irrigation regimes were more pronounced in the rhizosphere soil than in the bulk soil. Compared to the FI treatment, the CI treatment significantly increased the relative abundances of the G+ and Actinobacteria in the rhizosphere soil (p < 0.05). According to the PLFA-SIP, most of the labeled urea-derived C was incorporated into 16:1ω7c, 16:0 and 18:1ω7c under both treatments. Despite these general trends, the pattern of 13C incorporation into the PLFA pool differed between the treatments. The factor loadings of individual PLFAs suggested that 18:1ω7c, 16:1ω7c and 16:1ω5c were relatively enriched in urea-C in the bulk soil, while 17:1ω8c, i16:0 and 16:0 were relatively enriched in urea-C in the rhizosphere soil under different irrigation regimes. The loadings also confirmed that 10-me16:0, cy17:0 and cy19:0 were relatively enriched in urea-C under the CI treatment, whereas 14:0, a15:0 and 15:0 were relatively enriched in urea-C under the FI treatment. These results are helpful not only in revealing the interception mechanism of urea-C in soil but also in understanding the functions of key microbes in element cycles. [ABSTRACT FROM AUTHOR]

Crop residues and their derived biochar are frequently used for their potential to improve grain yield, soil fertility and carbon (C) sequestration. However, the effects of root are often overlooked, and the effects of chemical fertilizer (NPK) combined with root or its biochar on microbial community structure need further study. This study used 13C-labeled maize root, its biochar and soil with different fertilization for 8 years as materials and substrates. A 112-day incubation experiment was conducted to explore the effects of microbial community on the C processing. During incubation, the root-C (54.9%) mineralized significantly more than biochar-C (12.8%), while NPK addition significantly increased the root-C mineralization. Adding biochar alone did not significantly change the microbial community. Compared to the biochar treatment (BC), the root treatment (R) notably increased the contents of total phospholipid fatty acids (PLFAs), 13C-PLFA and the proportion of fungi and Gram-negative bacteria, but reduced the proportion of actinomycetes. The root mineralization was significantly correlated with the relative content of 13C-Gram-positive bacteria and 13C-fungi, while biochar mineralization was significantly correlated with the relative content of 13C-Gram-positive bacteria and 13C-actinomycetes. Notably, NPK addition significantly increased the contribution of biochar-C to PLFA-C pool, while decreasing the contribution of root-C. In summary, due to microbial adaptation to the lack of bioavailable C in biochar-amended soil, biochar can act as a buffer against the significant disturbance caused by NPK to microbial communities and native soil organic carbon (SOC), which contributes to the steady enhancement in soil C storage. Highlights: The addition of biochar alone for 8 consecutive years did not change the composition of the microbial community structure, but the total PLFA content increased significantly compared to the control. NPK addition reduced the proportion of microbial assimilation of root-C, while increasing the proportion of microbial assimilation of biochar-C. The effect of NPK on microbial biomass is short-lived, but the effect on microbial community structure is long-lasting. Biochar has a stronger buffering effect on the drastic changes in microbial communities and native SOC caused by NPK. [ABSTRACT FROM AUTHOR]

Introduction: Inside oil and gas pipelines, native microbial communities and different solid compounds typically coexist and form mixed deposits. However, interactions between these deposits (primarily consisting of mineral phases) and microorganisms in oil and gas systems remain poorly understood. Here, we investigated the influence of magnetite (Fe3O4), troilite (FeS), and silica (SiO2) on the microbial diversity, cell viability, biofilm formation, and EPS composition of an oil-recovered multispecies consortium. Methods: An oilfield-recovered microbial consortium was grown for 2 weeks in separate bioreactors, each containing 10 g of commercially available magnetite (Fe3O4), troilite (FeS), or silica (SiO2) at 40°C ± 1°C under a gas atmosphere of 20% CO2/80% N2. Results: The microbial population formed in troilite significantly differed from those in silica and magnetite, which exhibited significant similarities. The dominant taxa in troilite was the Dethiosulfovibrio genus, whereas Sulfurospirillum dominated in magnetite and silica. Nevertheless, biofilm formation was lowest on troilite and highest on silica, correlating with the observed cell viability. Discussion: The dissolution of troilite followed by the liberation of HS- (H2S) and Fe2+ into the test solution, along with its larger particle size compared to silica, likely contributed to the observed results. Confocal laser scanning microscopy revealed that the EPS of the biofilm formed in silica was dominated by eDNA, while those in troilite and magnetite primarily contained polysaccharides. Although the mechanisms of this phenomenon could not be determined, these findings are anticipated to be particularly valuable for enhancing MIC mitigation strategies currently used in oil and gas systems. [ABSTRACT FROM AUTHOR]

The rapid increase in reactive nitrogen (N) released into the environment by human activities has notably altered the structure and composition of forest soil microbial communities (SMCs), profoundly impacting the N cycle in terrestrial ecosystems. However, the response of soil microorganisms to nitrogen addition in different seasons is not clear. This study delved into how SMCs in a subtropical region of central Yunnan, China, specifically in an evergreen broad-leaved forest (EBLF), respond to N deposition during both the dry and wet seasons. Through high-throughput sequencing, we assessed the composition and structure of SMCs under varying N addition treatments across seasons, examining their interplay with soil chemical properties, enzyme activities, and community responses. The findings revealed significant outcomes following four years of N addition in the subtropical EBLF: (1) Significant changes were observed due to the interaction between N addition and seasonal changes. Soil pH significantly decreased, indicating increased soil acidification, particularly in the dry season. Increased moisture in the wet season mitigated soil acidification. (2) In the dry season, N addition led to a decrease in microbial richness and diversity. In the wet season, N addition increased microbial richness and diversity, alleviating the downward trend observed in the dry season. (3) N addition significantly impacted the composition of soil bacterial and fungal communities. Dominant fungal genera in the wet season were particularly sensitive to N addition. (4) Seasonal changes and N addition altered soil microbial community structures. Soil chemical properties and enzyme activities significantly influenced the microbial community structure. However, due to differences in soil moisture, the key environmental factors that regulate microbial communities have changed significantly during the dry and wet seasons. This study serves as a foundation for understanding how N deposition impacts SMCs in EBLF ecosystems in subtropical regions, offering valuable insights for the scientific management of forest ecological resources amidst global change trends. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: This study presents the initial findings on how rice cultivation impacts water quality and the microbial community structure in ponds where mandarin fish are being fed an artificial diet. The results indicated that rice cultivation plays a significant role in reducing nutrient salt levels in the water, thus regulating the overall aquatic environment. Furthermore, the cultivation of rice has been found to alter the composition of microbial communities in the water, leading to a decrease in diversity and affecting the abundance of bacteria involved in carbon, nitrogen, and phosphorus metabolism. The study identified Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, and Deinococcus-Thermus as the dominant bacterial phyla in ponds where mandarin fish are being fed an artificial diet. Additionally, it was observed that Proteobacteria showed a particular preference for proliferation in the aquatic environment with rice cultivation on the water surface. These results provide a valuable foundation for the potential application of aquaculture practices involving mandarin fish fed an artificial diet and rice floating beds. The culture of mandarin fish using artificial feed has been gaining increasing attention in China. Ensuring good water quality in the ponds is crucial for successful aquaculture. Recently, the trial of pond-based rice floating beds (PRFBs) in aquaculture ponds has shown promising results. This research assessed the impact of PRFBs on the microbial community structure and overall quality of the aquaculture pond, thereby enhancing our understanding of its functions. The results revealed that the PRFB group exhibited lower levels of NH4+-N, NO2−-N, NO3−-N, TN, TP, and Alk in pond water compared to the control group. The microbial diversity indices in the PRFB group showed a declining trend, while these indices were increasing in the control group. At the phylum level, there was a considerable increase in Proteobacteria abundance in the PRFB group throughout the culture period, suggesting that PRFBs may promote the proliferation of Proteobacteria. In the PRFB group, there was a remarkable decrease in bacterial populations related to carbon, nitrogen, and phosphorus metabolism, including genera Rhodobacter, Rhizorhapis, Dinghuibacter, Candidatus Aquiluna, and Chryseomicrobium as well as the CL500_29_marine_group. Overall, the research findings will provide a basis for the application of aquaculture of mandarin fish fed an artificial diet and rice floating beds. [ABSTRACT FROM AUTHOR]

BACKGROUND: Baijiu brewing is a complex and multifaceted multimicrobial co‐fermentation process, in which various microorganisms interact to form an interdependent micro‐ecosystem, subsequently influencing metabolic activities and compound production. Among these microorganisms, Bacillus, an important bacterial genus in the liquor brewing process, remains unclear in its role in shaping the brewing microbial community and its functional metabolism. RESULTS: A baijiu fermentation system was constructed using B. subtilis JP1 isolated from native jiupei (grain mixture) combined with daqu (a saccharifying agent) and huangshui (a fermentation byproduct). Based on high‐throughput amplicon sequencing analysis, it was evident that B. subtilis JP1 significantly influences bacterial microbial diversity and fungal community structure in baijiu fermentation. Of these, Aspergillus and Monascus emerge as the most markedly altered microbial genera in the jiupei community. Based on co‐occurrence networks and bidirectional orthogonal partial least squares discriminant analysis models, it was demonstrated that the addition of B. subtilis JP1 intensified microbial interactions in jiupei fermentation, consequently enhancing the production of volatile flavor compounds such as heptanoic acid, butyl hexanoate and 3‐methylthiopropanol in jiupei. CONCLUSION: B. subtilis JP1 significantly alters the microbial community structure of jiupei, enhancing aroma formation during fermentation. These findings will contribute to a broader application in solid‐state fermentation. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Microbial communities play a crucial role in the processes of material cycling, energy conversion, and information transfer in river water. Analyzing the distribution characteristics of microbial community structure is crucial for preserving the long-term stability of river water ecosystems. In order to investigate the structure characteristics of the microbial communities and the relationships between microbial communities and hydrochemical compositions in agricultural region and urban region of Qingshui River, a total of 20 river water samples, including 13 samples from the agricultural region and 7 samples from the urban region, were collected from the River. The hydrogeochemical methods, high-throughput sequencing technology, and bioinformatics analysis were used to determine the relationships between microbial communities and hydrochemical compositions in the different functional regions of the River. The results showed that river water is generally weakly alkaline water (8.35≤pH≤9.44). The chemical type of river water is mainly HCO3-Ca•Mg water (80%), followed by Cl-Ca•Mg water (20%). Hydrochemical compositions in agricultural region were mainly controlled by the carbonate dissolution and agricultural fertilization inputs, while these in the unban region were primarily affected by the upstream hydrochemical characteristics and unban discharges. The hardening of river bottoms and its banks resulted in lower level of microbial diversity in the urban region than that in the agricultural region, and further caused the differences in microbial community structure. Limnohabitans, Rhodobacter and Flavobacterium were identified as the main genus in the agricultural region, and Cyanobium&lowbar;PCC-6307, Limnohabitans and norank&lowbar;f&lowbar;norank&lowbar;o&lowbar;Chloroplast were the primary genus in the urban region. The order of the influence of hydrochemical factors on microbial community structure was NO3- (P=0.001)>SO42- (P=0.003)>DO(P=0.071)>pH(P=0.222), and among these NO3- emitted from agricultural fertilization has the most significant impact on the microbial community structure in the River. NO3- concentrition in river water was increased by the microbial nitrification process in the agricultural region, whereas it was decreased by microbial denitrification process between the agricultural region and the urban region. [ABSTRACT FROM AUTHOR]

Simple Summary: The utilization of reclaimed land and enhancement of its productivity are crucial for alleviating China's food production shortage. Previous research has indicated that co-cultivating rice with frogs can enhance soil fertility. However, there is limited research on the use of integrated rice–frog farming techniques to improve soil fertility on reclaimed barren land for enhanced food production efficiency. Therefore, this study evaluated the impact of rice–frog co-cultivation on soil fertility and microbial diversity of reclaimed land. Experimental plots were established for rice monoculture, low-density rice–frog co-cultivation, and high-density rice–frog co-cultivation. The study found that during the rice maturity period, the soil fertility in the plots with high-density rice–frog co-cultivation was significantly higher compared to the rice monoculture plots. Additionally, rice–frog co-cultivation increased the soil microbial diversity and altered the structure of the microbial community compared to the rice monoculture. This research indicates that compared with rice monoculture, rice–frog co-cultivation can enhance the soil fertility and microbial diversity of reclaimed land. This study provides a theoretical basis for the construction of integrated farming models on reclaimed land, offering new perspectives and opportunities for the efficient utilization of such land. Utilizing and improving the productivity of reclaimed land are highly significant for alleviating the problem of food production shortage in China, and the integrated rice–frog farming model can improve soil fertility. However, there are few studies on the use of integrated rice–frog farming technology to improve the fertility of reclaimed land and increase its efficiency in food production. Therefore, this study was conducted to evaluate the effects of the rice–frog co-cropping mode on the soil fertility and microbial diversity of reclaimed land. A rice monoculture group (SF), low-density rice–frog co-cropping group (SD, 5000 frogs/mu, corresponds to 8 frogs/m2), and high-density rice–frog co-cropping group (SG, 10,000 frogs/mu, corresponds to 15 frogs/m2) were established and tested. The contents of total nitrogen, soil organic matter, available potassium, and available phosphorus of the soil in the SG group were significantly higher than those in the SF group (p < 0.05) in the mature stage of rice. Compared with the SF group, the SD and SG groups improved the soil microbial diversity and changed the structure of the microbial community. This study indicates that compared with the rice monoculture mode, the rice–frog co-cropping pattern can improve the soil fertility, as well as microbial diversity, of reclaimed land. [ABSTRACT FROM AUTHOR]

Intercropping, a well-established agroecological technique designed to bolster ecological stability, has been shown to have a significant impact on soil health. However, the specific effects of tea/Trachelospermum jasminoides intercropping on the physicochemical properties and functional microbial community structure in practical cultivation have not been thoroughly investigated. In this study, we utilized high-throughput sequencing technology on the 16S/ITS rDNA genes to assess the impact of tea intercropping with T. jasminoides on the composition, diversity, and potential functions of the soil microbial community in tea gardens. The results indicated that the tea/T. jasminoides intercropping system significantly increased pH levels, soil organic matter, available nitrogen, phosphorus, potassium, and enzyme activity, ultimately augmenting soil nutrient levels. Furthermore, an in-depth analysis of the bacterial co-occurrence network and topological structure portrayed a more intricate and interconnected soil bacterial community in tea gardens. Remarkably, the abundance of beneficial genera, including Burkholderia, Mesorhizobium, Penicillium, and Trichoderma, underwent a substantial increase, whereas the relative abundance of pathogenic fungi such as Aspergillus, Fusarium, and Curvularia experienced a marked decline. Functional predictions also indicated a notable enhancement in the abundance of microorganisms associated with nitrogen and carbon cycling processes. In summary, the intercropping of tea and T. jasminoides holds the potential to enrich soil nutrient content, reshape the microbial community structure, bolster the abundance of functional microorganisms, and mitigate the prevalence of pathogenic fungi. Consequently, this intercropping system offers a promising solution for sustainable tea garden management, overcoming the limitations of traditional cultivation methods and providing valuable insights for sustainable agriculture practices. [ABSTRACT FROM AUTHOR]

Introduction: Microplastics (MPs), identified as emerging contaminants, have been detected across diverse environmental media. Their enduring presence and small size facilitate the adsorption of organic pollutants and heavy metals, leading to combined pollution effects. MPs also accumulate in the food chain thus pose risks to animals, plants, and human health, garnering significant scholarly attention in recent years. Aerobic granular sludge (AGS) technology emerges as an innovative approach to wastewater treatment. However, the impacts of MPs on the operational efficiency and microbial characteristics of AGS systems has been insufficiently explored. Methods: This study investigated the effects of varying concentration (10, 50, and 100 mg/L) of biodegradable MPs (Polylactic Acid, PLA) and nonbiodegradable MPs (Polyethylene Terephthalate, PET) on the properties of AGS and explored the underlying mechanisms. Results and discussions: It was discovered that low and medium concentration of MPs (10 and 50 mg/L) showed no significant effects on COD removal by AGS, but high concentration (100 mg/L) of MPs markedly diminished the ability to remove COD of AGS, by blocking most of the nutrient transport channels of AGS. However, both PLA and PE promoted the nitrogen and phosphorus removal ability of AGS, and significantly increased the removal efficiency of total inorganic nitrogen (TIN) and total phosphorus (TP) at stages II and III (P < 0.05). High concentration of MPs inhibited the growth of sludge. PET noticeably deteriorate the sedimentation performance of AGS, while 50 mg/L PLA proved to be beneficial to sludge sedimentation at stage II. The addition of MPs promoted the abundance of Candidatus_Competibacter and Acinetobacter in AGS, thereby promoting the phosphorus removal capacity of AGS. Both 50 mg/L PET and 100 mg/L PLA caused large amount of white Thiothrix filamentous bacteria forming on the surface of AGS, leading to deterioration of the sludge settling performance and affecting the normal operation of the reactor. Comparing with PET, AGS proved to be more resistant to PLA, so more attention should be paid to the effect of non-biodegradable MPs on AGS in the future. [ABSTRACT FROM AUTHOR]

In order to solve the problems of difficult selection of carbon sources and high cost of dosage in advanced treatment of wastewater treatment plant, denitrification biological filter was used to explore the denitrification performance of different carbon sources. In this study, the denitrification performance of three carbon sources (sodium acetate, ethanol and methanol) at different hydraulic retention time (HRT), nitrogen ratio (C/N) and influent NH4+-N concentration and the microbial community structure at different heights of the reactor were investigated. The results showed that under the condition of low carbon nitrogen ratio, as the HRT increased, the removal efficiency of NH4+-N and NO3--N in the effluent of three systems with sodium acetate ethanol and methanol as carbon sources gradually increased, and the accumulation of NO2--N in methanol system was the lowest in the three systems. With the gradual increase of carbon to C/N, the concentration of NH4+-N and NO3--N in the three systems gradually decreased. The effluent TN concentration of sodium acetate and methanol system was less than 1.5 mg/L when C/N was 6 and 5, which met the Class W of Environmental Quality Standard for Surface Water. With the increase of influent NH4+-N concentration, it led to the increase of NO2--N accumulation degree, resulting in the increase of effluent TN concentration. Carbon sources led to significant differences in the abundance of the three systems at the phylum level. The differences at the genus level were more obvious, and the total relative abundance of denitrifying bacteria was in the order of sodium acetate system > ethanol system > methanol system. The results of this study can provide a theoretical reference for the selection of carbon source and the use of dosage in waste-water treatment plants. [ABSTRACT FROM AUTHOR]

This study analyzed the effects of benzoic acid (BA) on the physicochemical properties and microbial community structure of perilla rhizosphere soil. The analysis was based on high-throughput sequencing technology and physiological and biochemical detection. The results showed that with the increase in BA concentration, soil pH significantly decreased, while the contents of total nitrogen (TN), alkaline nitrogen (AN), available phosphorus (AP), and available potassium (AK) significantly increased. The activities of soil conversion enzymes urease and phosphatase significantly increased, but the activities of catalase and peroxidase significantly decreased. This indicates that BA can increase soil enzyme activity and improve nutrient conversion; the addition of BA significantly altered the composition and diversity of soil bacterial and fungal communities. The relative abundance of beneficial bacteria such as Gemmatimonas, Pseudolabrys, and Bradyrhizobium decreased significantly, while the relative abundance of harmful fungi such as Pseudogymnoascus, Pseudoeurotium, and Talaromyces increased significantly. Correlation analysis shows that AP, AN, and TN are the main physicochemical factors affecting the structure of soil microbial communities. This study elucidates the effects of BA on the physicochemical properties and microbial community structure of perilla soil, and preliminarily reveals the mechanism of its allelopathic effect on the growth of perilla. [ABSTRACT FROM AUTHOR]

Background: Conventional biofilters, which rely on bacterial activity, face challenges in eliminating hydrophobic compounds, such as aromatic compounds. This is due to the low solubility of these compounds in water, which makes them difficult to absorb by bacterial biofilms. Furthermore, biofilter operational stability is often hampered by acidification and drying out of the filter bed. Methods: Two bioreactors, a bacterial biofilter (B-BF) and a fungal–bacterial coupled biofilter (F&B-BF) were inoculated with activated sludge from the secondary sedimentation tank of the Sinopec Yangzi Petrochemical Company wastewater treatment plant located in Nanjing, China. For approximately 6 months of operation, a F&B-BF was more effective than a B-BF in eliminating a gas-phase mixture containing benzene, toluene, ethylbenzene, and para-xylene (BTEp-X). Results: After operating for four months, the F&B-BF showed higher removal efficiencies for toluene (T), ethylbenzene (E), benzene (B), and para-X (p-Xylene), at 96.9%, 92.6%, 83.9%, and 83.8%, respectively, compared to those of the B-BF (90.1%, 78.7%, 64.8%, and 59.3%). The degradation activity order for B-BF and F&B-BF was T > E > B > p-X. Similarly, the rates of mineralization for BTEp-X in the F&B-BF were 74.9%, 66.5%, 55.3%, and 45.1%, respectively, which were higher than those in the B-BF (56.5%, 50.8%, 43.8%, and 30.5%). Additionally, the F&B-BF (2 days) exhibited faster recovery rates than the B-BF (5 days). Conclusions: It was found that a starvation protocol was beneficial for the stable operation of both the B-BF and F&B-BF. Community structure analysis showed that the bacterial genus Pseudomonas and the fungal genus Phialophora were both important in the degradation of BTEp-X. The fungal-bacterial consortia can enhance the biofiltration removal of BTEp-X vapors. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFASs) have attracted significant attention as a emerging environmental contaminant. The biological toxicities and ecological health risks associated with PFASs have emerged as a popular subject for ecotoxicology related research. PFASs have a detrimental impact on individual microbes in the environment. Furthermore, prolonged exposure to PFASs can disrupt the composition, structure and enzyme activity of the microbial community in the environment, disrupting the normal cycling of materials and energy in the ecosystem. This paper reviewed the impact of PFASs on microbial community structure and diversity across various environmental media, namely freshwater, marine and soil. Additionally, it summarizes the effects of enzyme activity and function in response to PFASs. Based on these findings, an assessment of the future direction of ecological risk assessment of PFASs was conducted to provide a theoretical basis and support for unbiased environmental and ecological risk assessment of PFASs. [ABSTRACT FROM AUTHOR]

Background and aims: Conservation tillage enhances soil aggregate function, —a key factor for promoting soil nutrient cycling and plant growth. However, there is a limited understanding of how tillage practices impact soil nutrients, enzymes and microbes distribution among different-sized aggregates, and their potential subsequent effects on other soil functions and processes. Methods: We conducted a long-term experiment involving maize (Zea mays L.) cultivation in a semiarid farming region in Northwest China. Four tillages were implemented: no-tillage, minimal tillage, fold-tillage, and sub-tillage. Soil aggregates were categorized based on size: <0.25 mm ('micro'), 0.25–2 mm ('small'), and > 2 mm ('macro'). We measured the nutrient contents, enzyme activity, enzymatic stoichiometry, and soil microbial community structure with each fraction, and assessed crop productivity. Results: The no-tillage treatment increased soil C content, microbial biomass, and P and N availability within micro-aggregates and bulk soil. It also enhanced enzymatic activity related to C and P acquisition and the C: N enzymatic ratio but decreased the N: P enzymatic ratio in micro-aggregates. Notably, no-tillage promoted straw and root biomass and crop yield compared to conventional tillage. Microbial community structure differed under the different tillage regimes and among aggregate size fractions, particularly under conventional tillage, but the tillage system did not affect alpha diversity. Conclusions: Our results highlight that long-term conservation tillage positively influenced soil aggregates by increasing carbon content and enzyme activity, thereby, reshaping the soil microbial community composition within aggregate size fractions in semiarid agroecosystems. [ABSTRACT FROM AUTHOR]

Modern coal chemical industry is an important means to realize the clean utilization of coal resources, the coal chemical sludge generated during the process of coal conversion process is a typical refractory solid waste restricting the development of coal chemical industry since its extremely high water content and the poor dewaterability. It has been documented that the dewaterability of coal chemical sludge is affected by the microbial community structure and water distribution characteristics; and thus, it is necessary to investigate the microbial community information and water distribution in coal chemical sludge to provide theoretical guidance for the high-efficiency sludge dewatering technology. In this study, coal-to-olefins sludge and coal-to-oil sludge were selected and the microbial community structure of the two sludge was obtained through analyzing 16s rRNA gene sequencing, and the water distribution was obtained by DSC and LF-NMR method. The results show that the different sewage treatment processes chosen by two coal chemical industries lead to certain differences in the microbial community structures of coal chemical sludge, Proteobacteria, Bacteroidetes and Chloroflexi are the dominant phylum in the two sludge. The LF-NMR method can more accurately measure the water distribution, and the water in the sludge can be classified into bound water, mechanical bound water and free water according. [ABSTRACT FROM AUTHOR]

Background: Previous research on whole-soil measurements has failed to explain the spatial distribution of soil carbon transformations, which is essential for a precise understanding of the microorganisms responsible for carbon transformations. The microorganisms involved in the transformation of soil carbon were investigated at the microscopic scale by combining 16S rDNA sequencing technology with particle-level soil classification. Methods: In this experiment,16S rDNA sequencing analysis was used to evaluate the variations in the microbial community structure of different aggregates in no-tillage black soil. The prokaryotic microorganisms involved in carbon transformation were measured before and after the freezing and thawing of various aggregates in no-tillage black soil. Each sample was divided into six categories based on aggregate grain size: >5, 2-5, 1-2, 0.5-1, 0.25-0.5, <0.25 mm, and bulk soil. Results: The relative abundance of Actinobacteria phylum in <0.25 mm aggregates was significantly higher compared to that in other aggregates. The Chao1 index, Shannon index, and phylogenetic diversity (PD) whole tree index of <0.25 mm aggregates were significantly smaller than those of in bulk soil and >5 mm aggregates. Orthogonal partial least-squares discrimination analysis showed that the microbial community composition of black soil aggregates was significantly different between <1 and >1 mm. The redundancy analysis (RDA) showed that the organic carbon conversion rate of 0.25--0.5 mm agglomerates had a significantly greater effect on their bacterial community structure. Moreover, humic acid conversion rates on aggregates <0.5 mm had a greater impact on community structure. The linear discriminant analysis effect size (LEfSe) analysis and RDA analysis were combined. Bradyrhizobium, Actinoplane, Streptomyces, Dactylosporangium, Yonghaparkia, Fleivirga, and Xiangella in <0.25 mm aggregates were positively correlated with soil organic carbon conversion rates. Blastococcus and Pseudarthrobacter were positively correlated with soil organic carbon conversion rates in 0.25--0.5 mm aggregates. In aggregates smaller than 1 mm, the higher the abundance of functional bacteria that contributed to the soil's ability to fix carbon and nitrogen. Discussion: There were large differences in prokaryotic microbial community composition between <1 and >1 mm aggregates. The <1 mm aggregates play an important role in soil carbon transformation and carbon fixation. The 0.25-0.5 mm aggregates had the fastest organic carbon conversion rate and increased significantly more than the other aggregates. Some genus or species of Actinobacteria and Proteobacteria play a positive role in the carbon transformation of <1 mmaggregates. Such analyses may help to identify microbial partners that play an important role in carbon transformation at the micro scale of no-till black soils. [ABSTRACT FROM AUTHOR]

Mixing with different broadleaf trees into the monocultures of Cunninghamia lanceolata is widely adopted as an efficient transformation of the pure C. lanceolata forest. However, it is unclear how native broad-leaved trees influence the belowground ecological environment of the pure C. lanceolata culture plantation in nutrient-poor soil of South China. Herein, we aimed to investigate how a long-time mixing with native broadleaf trees shape soil microbial community of the pure C. lanceolata forest across different soil depth (0-20cm and 20-40cm) and to clarify relationships between the modified soil microbial community and those affected soil chemical properties. Using high-throughput sequencing technology, microbial compositions from the mixed C. lanceolata-broadleaf forest and the pure C. lanceolata forest were analyzed. Network analysis was utilized to investigate correlations among microorganisms, and network robustness was assessed by calculating network natural connectivity. Results demonstrated that the content of soil microbial biomass carbon and nitrogen, total phosphorus and pH in mixed forest stand were significantly higher than those in pure forest stand, except for available phosphorus in topsoil (0-20cm). Simultaneously, the mixed C. lanceolata-broadleaf forest has a more homogeneous bacterial and fungal communities across different soil depth compared with the pure C. lanceolata forest, wherein the mixed forest recruited more diverse bacterial community in subsoil (20-40cm) and reduced the diversity of fungal community in topsoil. Meanwhile, the mixed forest showed higher bacterial community stability while the pure forest showed higher fungal community stability. Moreover, bacterial communities showed significant correlations with various soil chemical indicators, whereas fungal communities exhibited correlations with only TP and pH. Therefore, the mixed C. lanceolata-broadleaf forest rely on their recruiting bacterial community to enhance and maintain the higher nutrient status of soil while the pure C. lanceolata forest rely on some specific fungi to satisfy their phosphorus requirement for survive strategy. [ABSTRACT FROM AUTHOR]

To investigate the microbial diversity and the main pathogenic microorganisms of Fraxinus mandshurica leaves with different degrees of brown spot disease, and to analyze the control methods to maintain the ecological safety and enhance the economic benefits of Fraxinus mandshurica plantation forests, leaves infected with brown spot disease to varying degrees at Maoershan Experimental Forest Farm were collected,and the microbial community structure and species composition of Fraxinus mandshurica leaves were determined and analyzed using high-throughput sequencing technology. A total of 1 026 fungal operational taxonomic units (OUT) and 322 bacterial OUTs were obtained before and after the disease in the three groups of samples. Among the bacteria, the phyla Proteobacteria and Actinobacteriota were the dominant phyla; the genera Sphingomonas, Acidibacter and Bradyrhizobium were the main dominant genera. Among the fungi, the phyla Ascomycota and Basidiomycota were the dominant phyla; the genera Vishniacozyma, Septoria, and Hannaella were the dominant genera. There were no significant differences in bacterial diversity and community structure among the three groups of samples, and significant differences in fungal diversity and community structure. It was preliminarily speculated that the Cercospora was a pathogenic bacterium, but its pathogenicity needed further study. [ABSTRACT FROM AUTHOR]

The diversity of microbial communities in rhizosphere soil and non-rhizosphere soil was investigated in Juglans mandshurica plantation in Liaodong Mountain, and the relationship between the diversity and physical or chemical characteristics of soil were also studied. The results showed that most of chemical characteristics such as pH, total carbon, total nitrogen, total phosphorus and available phosphorus in rhizosphere soils were higher than that in non-rhizosphere soils significantly. The main factors affecting soil bacterial and fungal community structure are soil pH and available phosphorus (bacteria) and available nitrogen (fungi), respectively. Significant difference in the number of biomaker between rhizosphere and non-rhizosphere soils was detected for fungal, but not for bacteria. On contrast, significant difference of the diversity indexes between rhizosphere and non-rhizosphere soils were detected for bacteria, but not for fungi. These differences between rhizosphere and non-rhizosphere soils, and also between bacteria and fungi might caused by roots physiological metabolism of J. mandshurica. The dominant microbial groups are Actinobacteriota, Proteobacteria and Acidobacteriota (bacteria) and Ascomycota (fungi), which accounted for about 80% of relative abundance of bacteria or fungi. These results will provide the theoretical and scientific basis for the sustainable management and improvement of soil fertility of J. mandshurica plantation. [ABSTRACT FROM AUTHOR]

Due to the rapid development of animal husbandry, the associated environmental problems cannot be ignored, with the management of livestock and poultry manure emerging as the most prominent issue. Composting technology has been widely used in livestock and poultry manure management. A deeper understanding of the nitrogen conversion process during composting offers a theoretical foundation for selecting compost substrates. In this study, the effects of sawdust (CK) and spent mushroom compost (T1) as auxiliary materials on nitrogen as well as microbial structure in the composting process when composted with chicken manure were investigated. At the end of composting, the nitrogen loss of T1 was reduced by 17.18% relative to CK. When used as a compost substrate, spent mushroom compost accelerates the succession of microbial communities within the compost pile and alters the core microbial communities within the microbial community. Bacterial genera capable of cellulose degradation (Fibrobacter, Herbinix) are new core microorganisms that influence the assimilation of nitrate reduction during compost maturation. Using spent mushroom compost as a composting substrate increased the enzyme activity of nitrogen assimilation while decreasing the enzyme activity of the denitrification pathway. [ABSTRACT FROM AUTHOR]

Aim: Soil microbes can significantly influence restoration outcomes via interaction with plant community assembly processes, yet knowledge about variation in soil microbial communities – in particular functional variation – during oldfield succession is limited. Methods: We divided a well-dated successional chronosequence on the Tibetan Plateau into five stages: stage 1 (continued arable land), stage 2 (arable abandoned for 2 years), stage 3 (arable abandoned for 10 years), stage 4 (arable abandoned for 20 years), and natural grassland. We investigated the changes in taxonomic and functional composition of bacterial and fungal communities in these successional stages. Results: The richness of bacterial and fungal communities had a unimodal relationship with successional age, as the both were initially low and decreased again in natural grasslands. These changes were more correlated to soil properties. For both bacterial and fungal communities, taxonomic similarity to natural grasslands increased monotonously with successional age. The functional composition of bacterial communities shifted with successional age towards increased importance of strains involved in the C cycle rather than the N cycle, due to higher plant richness. For fungal communities, saprotrophs showed an increasing trend with successional age although low relative abundance in natural grasslands, which was regulated by belowground biomass. Symbiotrophs did not change during succession, but pathotrophic fungal relative abundance decreased rapidly after agricultural abandonment because of increased plant richness. Conclusions: Overall, twenty years of oldfield succession did not appear to restore richness of soil bacterial and fungal communities to the levels of natural grasslands. Community taxonomic and functional composition in successional stages up to 20 y old were also different from natural grasslands. Our results suggest more important role of plant community than microbial community to soil nutrient cycling during restoration in oldfields. [ABSTRACT FROM AUTHOR]

The Barents Sea shelf is one of the most economically promising regions in the Arctic in terms of its resources and geographic location. However, benthic microbial communities of the northeastern Barents Sea are still barely studied. Here, we present a detailed systematic description of the structures of microbial communities located in the sediments and bottom water of the northeastern Barents Sea based on 16S rRNA profiling and a qPCR assessment of the total prokaryotic abundance in 177 samples. Beta- and alpha-diversity analyses revealed a clear difference between the microbial communities of diverse sediment layers and bottom-water fractions. We identified 101 microbial taxa whose representatives had statistically reliable distribution patterns between these ecotopes. Analysis of the correlation between microbial community structure and geological data yielded a number of important results—correlations were found between the abundance of individual microbial taxa and bottom relief, thickness of marine sediments, presence of hydrotrolite interlayers, and the values of pH and Eh. We also demonstrated that a relatively high abundance of prokaryotes in sediments can be caused by the proliferation of Deltaproteobacteria representatives, in particular, sulfate and iron reducers. [ABSTRACT FROM AUTHOR]

Heavy metal (HMe) pollution in regions with mining and metallurgy activities is known to be a serious environmental problem worldwide. Hydrological processes contribute to the dissemination of HMes (drainage, precipitation, flow rate). The aim of the present study is to investigate the microbial community structure in ten river sediments sampled in different regions of East Kazakhstan, which are contaminated with HMes. The overall degree of sediment contamination with HMes (Cr, Cu, Zn, Pb, and Cd) was assessed using the pollution index Zc, which ranged from 0.43 to 21.6, with the highest in Ridder City (Zc = 21.6) and Ust-Kamenogorsk City, 0.8 km below the dam of the hydroelectric power station (Zc = 19.6). The tested samples considerably differed in organic matter, total carbon, nitrogen, and phosphorus content, as well as in the abundance of HMe-related functional gene families and antibiotic resistance genes. Metagenomic analysis of benthic microorganisms showed the prevalence of Proteobacteria (88.84–97.61%) and Actinobacteria (1.21–5.98%) at the phylum level in all samples. At the class level, Actinobacteria (21.68–57.48%), Betaproteobacteria (19.38–41.17%), and Alphaproteobacteria (10.0–39.78%) were the most common among the classified reads. To the best of our knowledge, this is the first study on the metagenomic characteristics of benthic microbial communities exposed to chronic HMe pressure in different regions of East Kazakhstan. [ABSTRACT FROM AUTHOR]

In this communication, we present an innovative approach leveraging advanced Machine Learning (ML) and Artificial Intelligence (AI) techniques, specifically the Non-Negative Matrix Factorization (NMF) method, to analyze downward and upward light spectra collected by Hyperspectral Ocean Color Radiometer (HyperOCR, HOCR) sensors in the water column. Our work focuses on the development of a robust and efficient tool for unraveling the structure and activities of natural microbial assemblages in the ocean. By applying the NMF method to HyperOCR data, we successfully extracted five spectral signatures, representing unique patterns in the data. These signatures were instrumental in predicting the abundances of various microbial components, including bacteria, heterotrophic nanoflagellates, and picoeukaryotes, showcasing the potential of ML and AI in advancing oceanographic studies. To validate these methods, the study area included a shallow coastal area under the influence of freshwater inflow and an open offshore area with a depth of 100 m. The study sites in coastal and offshore waters (Kaštela Bay and Stončica Vis, respectively) had significantly different hydrographic and microbiological characteristics. Kaštela Bay had lower temperatures and salinity than the site on Vis. We have demonstrated prediction of the structure of the microbial community through application of different AI and ML methods with specific HOCR sensors. [ABSTRACT FROM AUTHOR]

High‐throughput sequencing was used to define microbial community structure and GC–MS to identify volatile flavor substances during fermentation of corn yellow wine, and results were analyzed by multivariate statistical analysis. Seventeen bacterial phyla, 239 bacterial genera, 4 fungal phyla, and 18 fungal genera were found and changes in community structure occurred during fermentation. Twenty‐four volatile flavor substances, including 14 esters and 5 alcohols, were detected and changes during fermentation recorded. Sixteen microbial genera correlated with volatile flavor substances and Weissella, Lactobacillus, Pseudomonas, Rhodotorul, and Kwoniella had significant correlation with ethyl esters and higher alcohols. Micro‐organisms thus influence flavor development during corn yellow wine fermentation. [ABSTRACT FROM AUTHOR]

Rebuilding soil healthy microbiota is very important for preventing bacterial wilt. A 3-year-long field trial was conducted in China as follows: T1 (conventional fertilization), T2 (T1 + liming), T3 (T1 + bioorganic fertilizer), and T4 (T2 + bioorganic fertilizer). Fluorescence quantitative PCR and high-throughput sequencing were employed to study the dynamics of Ralstonia solanacearum population, microbial community, and network organizations between bacteria and quality-related variables. After 3 years of bioremediation, the control efficacy of tobacco bacterial wilt reached 61.30% and the occurrence delayed by approximately 40 days in T4, which had the highest tobacco yield and output value. The pathogen population of T4 remained below 106 copies/g soil during the entire growth period. Role-shifts prevailed among the network members. Microbes were unipathically associated with variables in T1 but multiplex in T4. In conclusion, soil bioremediation rebuilds a healthy soil microbiota and forms a more interactive and relevant micro-system, thus effectively controlling tobacco bacterial wilt. Key points: • This is the first time to effectively bio-control tobacco bacterial wilt in practical production in China, as well as to high-efficiently use the organic waste, thus promoting the organic cycling of the environment. • Soil bioremediation can effectively control soil-borne disease by rebuilding soil healthy microbiota and reducing abundance of pathogenic bacteria, thereby to prevent the soil borne disease occurrence. • After the soil remediated, microbes associated with soil and tobacco characteristics changed from unipathical to multiplex, and the keystone species play different roles compared with the original soil, thus signifying the complexity of multi-species interactions and achieving a closely relevant micro-system, which was ecologically meaningful to the environment. [ABSTRACT FROM AUTHOR]

Background: To determine the differences in the microbial communities in the Camellia sinensis L. hairy root, lateral root, and main root rhizospheres in Anping Village, Kaiyang County, Guizhou Province, the community structure, diversity, and main dominant species of bacteria and fungi in different parts of the soil were analyzed by ITS and 16S sequencing. Results: In the rhizosphere soil of the main root, lateral root, and hairy root of Camellia sinensis L., there were significant differences in the diversity and richness of the bacterial and fungal communities. The bacterial diversity was the highest and the fungal richness was the lowest in the rhizosphere soil of the main root. In the bacterial community, Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi, and Gemmatimonadetes were the common dominant bacteria. Rhodospirillaceae, Bradyrhizobiaceae, Hyphomicrobiaceae, Solibacteraceae, and Koribacteraceae were the common dominant bacteria in the rhizosphere soil of different parts of the root system, but the relative abundance of bacteria in different parts of the rhizosphere soil varied greatly. The dominant groups of fungal communities in different parts of the rhizosphere soil were Basidiomycota, Ascomycota, Mortierellomycota, and Sebacinaceae. The structure of the fungal community is similar in different parts. Conclusions: Compared with the different parts of the hairy root, lateral root, and main root of rhizosphere soil of Camellia sinensis L. in Anping village, it was found that the abundance of fungal community decreased with the increase of bacterial community abundance, and there were significant differences in bacterial community diversity and structure. However, the fungal community maintained stability among different parts. [ABSTRACT FROM AUTHOR]

Surface soils of five representative land-use types were collected in Yellow River Delta (YRD) and determined for concentrations of heavy metals and soil properties. These data were used to assess the heavy metal pollution status, and discuss the effects of heavy metals and soil properties on microbial community structure. Results showed that overall heavy metal pollution status in YRD was not serious except for the oilfield area. At the phylum level, the dominant species in the soil samples of YRD were Proteobacteria, Actinobacteriota, and Chloroflexi. The bacterial community structures varied significantly among different land-use types, and TN, TP, pH, Ni, and As had the greatest impact on microbial community structure. Moreover, the phylum Actinobacteriota and Chloroflexi were positively correlated with As, Ni, Cu, Zn, and Cd, indicating possible tolerance to these heavy metals. These results could be helpful for understanding the variations of soil microbial communities in YRD. [ABSTRACT FROM AUTHOR]

Microorganisms play a major role in the degradation of organic matter in sediments. However, the spatiotemporal variation and factors affecting these communities are not clearly understood. At the same time, conventional hydrographic and geochemical parameters do not offer an accurate assessment of transitional ecosystems. PLFA biomarkers which are specific to different taxonomic groups of microorganisms are able to provide a detailed assessment of the community composition in an environment and reflect a more direct assessment of the biological health of transitional ecosystems. We, therefore, conducted a comparison of PLFA biomarkers at four stations (Barmouth, B; Vaduthala, V; Munambam, M; and Arookutty, A) during three seasons (pre-monsoon, PRE; monsoon, MON; and post-monsoon, POST) in the Cochin estuary (CE). Each of the stations represented either a reference point (B), high pollution (V), high salinity (M), or low pollution (A). The communities determined using PLFA profiles could be categorized into six major groups with each group capable of reflecting the state of the ecosystem which correlated with the conventional parameters. The six groups were: G + ve Bacillota (formerly Firmicutes) and G-ve anaerobes (G-I), G-ve aerobic prokaryotes (G-II), ectomycorrhizal fungi (G-III), arbuscular mycorrhizae (G-IV), type-I methanotrophs (G-V), and microeukaryotes (G-VI). The prokaryotes were predominant in sediments amounting to over 78% of the total PLFAs detected, followed by the microeukaryotes. The freshwater-influenced stations were partially anaerobic in nature during PRE and MON and were mainly affected by both marine and terrestrial organic matter inputs, at times prominent in sewage matter. During POST season, CE behaves uniformly, especially in station M. Salinity and DO of BW and texture and organic matter of the sediment were the driving forces for microbial community structure. The reduced presence of cyclopropane fatty acids suggested that the CE was not under any stress during the study period. Our results using PLFA-based community profiling not only provide the fundamental information required to quickly access the impact of stress and other environmental inputs on the CE but also offer a more robust and realistic assessment of the nature of microbial communities in the ecosystem. A periodic and systemic assessment of PLFA profiles at these stations in CE throughout the year will enable the generation of enough metadata enabling a better understanding of this ecosystem and its efficient management in the long term. [ABSTRACT FROM AUTHOR]

To evaluate soil environmental quality of introduced new crops and other traditional crops, and to understand the importance of response of soil microbial community to heavy metal stress, rhizosphere soil samples of different land use types (Sphagnum farming, rice field, grassland and bare land) in Dading Village, Duyun City, Guizhou Province of China were selected as research objects. The differences of soil chemical properties, heavy metal concentration and microbial community among different land use types were compared. The abundance and structural diversity of microbial communities in soil samples were analyzed by 16S rDNA sequencing, the relationship between soil pollution characteristics and microbial community in farmland was studied. The results showed that the different land use types planting different agricultural products under the same growing environment were subject to different heavy metal pollution. Soil chemical properties and heavy metals had significant effects on the soil microbial community. Proteobacteria, Actinobacteriota and Acidobacteriota were the most dominant groups of bacteria. The soil microorganisms responded more actively to the variability of pH, SOM and AK contents, although the variability was not high. With the increase of pH value, the abundance of the dominant species Proteobacteria also increased. Verrucomicrobiota had a better tolerance to the heavy metal Hg. Verrucomicrobiota and Firmicutes had strong resistance to the heavy metal Cd. These results deepen our understanding of the changes and aggregation of microorganisms under different land use patterns in heavy-metal contaminated farmland soils. [ABSTRACT FROM AUTHOR]

Coffee is an important cash crop worldwide, but it has been plagued by serious continuous planting obstacles. Intercropping with Areca catechu could alleviate the continuous planting obstacle of coffee due to the diverse root secretions of Areca catechu. However, the mechanism of Areca catechu root secretion in alleviating coffee continuous planting obstacle is still unclear. The changes of coffee rhizosphere soil microbial compositions and functions were explored by adding simulated root secretions of Areca catechu, the primary intercropping plant species (i.e., amino acids, plant hormone, organic acids, phenolic acids, flavonoids and sugars) in current study. The results showed that the addition of coffee root exudates altered soil physicochemical properties, with significantly increasing the availability of potassium and organic matter contents as well as promoting soil enzyme activity. However, the addition of plant hormone, organic acids, or phenolic acids led to a decrease in the Shannon index of bacterial communities in continuously planted coffee rhizosphere soil (RS-CP). The inclusion of phenolic acids specifically caused the decrease of fungal Shannon index. Plant hormone, flavonoids, phenolic acids, and sugars increased the relative abundance of beneficial bacteria with reduced bacterial pathogens. Flavonoids and organic acids increased the relative abundance of potential fungal pathogen Fusarium. The polyphenol oxidase, dehydrogenase, urease, catalase, and pH were highly linked with bacterial community structure. Moreover, catalase, pH, and soil-available potassium were the main determinants of fungal communities. In conclusion, this study highlight that the addition of plant hormone, phenolic acids, and sugars could enhance enzyme activity, and promote synergistic interactions among microorganisms by enhancing the physicochemical properties of RS-CP, maintaining the soil functions in coffee continuous planting soil, which contribute to alleviate the obstacles associated with continuous coffee cultivation. [ABSTRACT FROM AUTHOR]

The realization of low-cost and high-standard nutrients removal are not acquired effectively in conventional pre-denitrification biological nitrogen removal processes (e.g., anaerobic/anoxic/oxic (A/A/O) process) for the treatment of domestic sewage. In this study, a pilot-scale bioreactor system based on the synergism of denitrifying phosphorus removal (DPR) and endogenous denitrification (ED) was proposed for advanced nutrients removal, which was operated under alternating anaerobic/oxic/anoxic (A/O/A) mode with no extracellular carbon source in the anoxic stage. The results showed that A/O/A and A/A/O systems were successfully established and operated in four stages with different mixed liquor suspended solid (MLSS, I: 3.32 ± 0.25 g/L, II: 5.89 ± 0.94 g/L, III: 8.66 ± 0.51 g/L, IV: 9.11 ± 5.72 g/L). Compared with the A/A/O system, the A/O/A system showed significantly higher nitrogen and phosphorus removal effectiveness within hydraulic retention time of 10 h. At MLSS of 8.66 ± 0.51 g/L, the A/O/A system could achieve simultaneously efficient removal of COD (91.47% ± 2.06%, 2.97 ± 0.26 mg COD/(g MLSS·h)), NH 4 +-N (97.27% ± 1.23%, 0.37 ± 0.06 mg NH 4 +-N/(g MLSS·h)), TN (89.94% ± 1.47%, 0.45 ± 0.03 mg TN/(g MLSS·h)), and PO 4 3--P (96.67% ± 0.88%, 0.04 ± 0.01 mg PO 4 3--P/(g MLSS·h)), and the effluent concentrations of COD, NH 4 +-N, TN, and PO 4 3--P were 24.0 ± 3.1, 0.9 ± 0.4, 4.4 ± 0.6, and 0.13 ± 0.03 mg/L, respectively. In addition, microbial community results indicated that denitrifying polyphosphate accumulating organisms and endogenous denitrifiers synergistically enhanced the nutrients removal capacity in the A/O/A system. Overall, this work provides new insight for further scaling and optimization of the A/O/A system. [ABSTRACT FROM AUTHOR]

Insects harbor diverse assemblages of bacterial and fungal symbionts, which play crucial roles in host life history. Insects and their various symbionts represent a good model for studying host–microbe interactions. Phylosymbiosis is used to describe an eco-evolutionary pattern, providing a new cross-system trend in the research of host-associated microbiota. The phylosymbiosis pattern is characterized by a significant positive correlation between the host phylogeny and microbial community dissimilarities. Although host–symbiont interactions have been demonstrated in many insect groups, our knowledge of the prevalence and mechanisms of phylosymbiosis in insects is still limited. Here, we provide an order-by-order summary of the phylosymbiosis patterns in insects, including Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, and Lepidoptera. Then, we highlight the potential contributions of stochastic effects, evolutionary processes, and ecological filtering in shaping phylosymbiotic microbiota. Phylosymbiosis in insects can arise from a combination of stochastic and deterministic mechanisms, such as the dispersal limitations of microbes, codiversification between symbionts and hosts, and the filtering of phylogenetically conserved host traits (incl., host immune system, diet, and physiological characteristics). [ABSTRACT FROM AUTHOR]

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Polystyrene (PS) and magnetic polystyrene (MPS) materials have been used extensively in wastewater treatment. In this research, a 55-day anaerobic/oxic process was carried out to evaluate the effects of PS and MPS on microorganisms under aerobic and anaerobic conditions. Scanning electron microscopy results revealed differences in the entanglement state of the sludge with the biocarrier due to differences in surface morphology. High-throughput sequencing analysis showed that the microbial communities differed considerably in the presence of PS and MPS addition under both aerobic and anaerobic conditions. The highest abundance and diversity were observed in the PS reactor, with 929 observed species and a PD_whole_tree index of 91.58 under anaerobic conditions. MPS promoted the enrichment of bacteria related to nitrogen recycling such as Nitrospirota which increased from 1.13% in the seeding sludge to 3.48% and 10.07% in the aerobic reactors with PS and MPS, respectively. Moreover, advanced analysis showed that PS inhibited many microbial functions (e.g., protein export, nitrogen metabolism), and MPS alleviated this inhibition. This study provides significant insights into the microbial effects of PS and MPS and may shed light on biocarrier selection in future studies. [ABSTRACT FROM AUTHOR]

Food chain contamination by soil lead (Pb), beginning with Pb uptake by leafy vegetables, is a threat to food safety and poses a potential risk to human health. This study highlights the importance of two ecologically different earthworm species (the anecic species Amynthas aspergillum and the epigeic species Eisenia fetida) as the driving force of microbial hotspots to enhance Pb accumulation in the leafy vegetable Brassica campestris at different Pb contamination levels (0, 100, 500, and 1,000 mg·kg-1). The fingerprints of phospholipid fatty acids (PLFAs) were employed to reveal the microbial mechanism of Pb accumulation involving earthworm-plant interaction, as PLFAs provide a general profile of soil microbial biomass and community structure. The results showed that Gram-positive (G+) bacteria dominated the microbial community. At 0 mg·kg-1 Pb, the presence of earthworms significantly reduced the total PLFAs. The maximum total of PLFAs was found at 100 mg·kg-1 Pb with E. fetida inoculation. A significant shift in the bacterial community was observed in the treatments with E. fetida inoculation at 500 and 1,000 mg·kg-1 Pb, where the G+/G- bacteria ratio was significantly decreased compared to no earthworm inoculation. Principal component analysis (PCA) showed that E. fetida had a greater effect on soil microbial hotspots than A. aspergillum, thus having a greater effect on the Pb uptake by B. campestris. Redundancy analysis (RDA) showed that soil microbial biomass and structure explained 43.0% (R² = 0.53) of the total variation in Pb uptake by B. campestris, compared to 9.51% of microbial activity. G- bacteria explained 23.2% of the total variation in the Pb uptake by B. campestris, significantly higher than the other microbes. The Mantel test showed that microbial properties significantly influenced Pb uptake by B. campestris under the driving force of earthworms. E. fetida inoculation was favorable for the G- bacterial community, whereas A. aspergillum inoculation was favorable for the fungal community. Both microbial communities facilitated the entry of Pb into the vegetable food chain system. This study delivers novel evidence and meaningful insights into how earthworms prime the microbial mechanism of Pb uptake by leafy vegetables by influencing soil microbial biomass and community composition. Comprehensive metagenomics analysis can be employed in future studies to identify the microbial strains promoting Pb migration and develop effective strategies to mitigate Pb contamination in food chains. [ABSTRACT FROM AUTHOR]

[Objective] The restoration of soil ecological functions following the reclamation of residential land is a crucial technical issue in urban land resource management research. [ Method] In the present study, microcosm experiments were conducted to investigate the effects of planting different grass species ( Festuca elata, Deschampsia grass, and Lolium perenne) on the bacterial and fungal community structure of reclaimed residential land, with natural recovery ( NER) as the control. [ Result] ( i) The fungal abundance in reclaimed residential soil was higher than that of bacteria, although the number of bacterial species was greater than that of fungi. (ii) Planting grasses significantly regulated the community structure of soil bacteria and fungi, with certain bacteria and fungi showing a significant increase in relative abundance, such as Actinobacteria, Chloroflexi, Planctomycetes, and Basidiomycota, which were all increased by more than five times. (iii) Grass plants had a greater impact on soil bacteria compared to fungi. At the phylum level, 13 bacteria significantly responded to the treatments, in contrast to only two fungi. ( iv) Planting grasses reduced the abundance of Sphingomonas but promoted the proliferation of specific fungal species, resulting in functional substitution. ( v) Seminibacterium, Betaproteobacteria, Ohtaekwangia and Streptococcus were a class of indicator bacteria that mainly characterized the cultivation of grass in mudslides. (vi) Planting grasses were more likely to promote the growth and reproduction of strongly associated fungal species in the soil, so the fungal groups associated with different grasses might also vary. [ Conclusion] After the reclamation of homesteads, the soil microbial function mainly focuses on the rapid decomposition of organic materials to supply plants, while grass plant species can achieve targeted restoration of soil ecological function by adjusting the soil microbial community structure. [ABSTRACT FROM AUTHOR]