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Livestock manure treatment technology and composting and its products have been widely used in agricultural soil. However, little was known about the variations in the fate of pathogens and the factors affecting their pathogenic ability during this process, which posed threats to ecological safety and public health globally. This study used a metagenomic approach to profile the behaviors of pathogens during peroxydisulfate composting. Results showed that Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Burkholderia pseudomallei, and Mycobacterium tuberculosis were the main secretors of virulence factors (VFs) in composting system; their abundance and the virulence factor–related genes they carried were better downregulated under the role of peroxydisulfate. In addition, peroxydisulfate composting ensured the lower moisture, weakening the swimming mobility behavior of pathogens through suppressing the abundance of genes associated with flagellar formation, and impaired the communication between pathogens by regulating quorum sensing (QS)– and quorum quenching (QQ)–related genes. Moreover, reduced abundance of resistomes restricted pathogens disseminating infection. In summary, this study provided useful strategies in managing pathogen pathogenic ability during composting based on pathogenic source (pathogens), pathway (VFs), influencing factors (QS/QQ, physicochemical habitats), and resistomes. [ABSTRACT FROM AUTHOR]

Xylanase is commonly thought to effectively cooperate with cellulase to promote the bioconversion of lignocellulose. In this study, a novel xylanase, SipoEnXyn10A (Xyn10A), previously identified from Streptomyces ipomoeae, was employed to investigate its synergetic effects on sugarcane bagasse (SCB) transformation. It was shown that the relative increase in reducing sugars reached up to 65%, with enhanced yields of glucose and xylose by 78% and 50%, respectively, in the case of the replacement of cellulase with an equivalent amount of Xyn10A at an enzyme loading of 12.5%. The highest degrees of synergy (DS) for glucose and xylose could reach 2.57 and 1.84. Moreover, the hydrolysis rate increased evidently, and the reaction time to reach the same yield of glucose and xylose was shortened by 72 h and 96 h, respectively. This study on synergistic mechanisms demonstrated that the addition of Xyn10A could cause the destruction of substrates' morphology and the dissolution of lignin components but could not change the accessibility and crystallinity of substrate cellulose. The joint effect of cellulase and xylanase during the hydrolysis process was thought to result in a synergistic mechanism. [ABSTRACT FROM AUTHOR]

Humus (HS) reservoirs can embed microbial necromass (including cell wall components that are intact or with varying degrees of fragmentation) in small pores, raising widespread concerns about the potential for C/N interception and stability in composting systems. In this study, fresh cow manure and sawdust were used for microbial solid fermentation, and the significance of microbial residues in promoting humification was elucidated by measuring their physicochemical properties and analyzing their microbial informatics. These results showed that the stimulation of external carbon sources (NaHCO3) led to an increase in the accumulation of bacterial necromass C/N from 6.19 and 0.91 µg/mg to 21.57 and 3.20 µg/mg, respectively. Additionally, fungal necromass C/N values were about 3 times higher than the initial values. This contributed to the increase in HS content and the increased condensation of polysaccharides and nitrogen-containing compounds during maturation. The formation of cellular debris mainly depends on the enrichment of Actinobacteria, Proteobacteria, Ascomycota, and Chytridiomycota. Furthermore, Euryarchaeota was the core functional microorganism secreting cell wall lytic enzymes (including AA3, AA7, GH23, and GH15). In conclusion, this study comprehensively analyzed the transformation mechanisms of cellular residuals at different profile scales, providing new insights into C/N cycles and sequestration. [ABSTRACT FROM AUTHOR]

Heavy metal pollution from compost is one of the most concerned environmental problems, which poses a threat to the ecosystem and human health. This study aims to reveal the heavy metal tolerance and detoxification mechanism mediated by heavy metal resistance genes (HMRGs) in compost habitat through metagenomics combined with chemical speciation analysis of heavy metals. The results showed that there were 37 HMRGs corresponding to 7 common heavy metal(loid)s in composting, and they had the ability to transform heavy metals into stable or low-toxic speciation by regulating enzyme transport, redox, methylation, etc. This study summarized the heavy metal metabolism pathway mediated by HMRGs, providing a new perspective for understanding the transformation of heavy metals in the composting process. [ABSTRACT FROM AUTHOR]

Enhancing carbon fixation in the composting process was of great significance in the era of massive generation of organic solid waste. In this study, the experimental results showed that the contents of dissolved organic matter (DOM) in the experimental group (CT) were 37.58% higher than those in the control group (CK). The CO2 emission peaked on day 5, and the value of CK was 1.34 times that of CT. Significant differences were observed between the contents of sulfur fractions in CT and CK. This phenomenon may be due to the suppression of sulfur-reducing gene expression in CT. On day 51 of composting, the abundance of sulfur-oxidizing bacteria (SOB) Rhodobacter (5.33%), Rhodovulum (14.76%), and Thioclava (23.83%) in CT was higher than that in CK. In summary, the composting fermentation regulated by Fe2(SO4)3 increased the sulfate content, enhanced the expression of sulfur-oxidizing genes and SOB, and ultimately promoted carbon sequestration during composting. [ABSTRACT FROM AUTHOR]

Carbon emission is the main cause of carbon loss during composting. This study investigated the effect of bamboo biochar addition to compost on carbon dioxide (CO2) release and fixation through metagenomics sequencing. The results showed that the addition of biochar enriched the relative abundance of ribulose-1,5-diphosphate carboxylase/oxygenase (RuBisCO) gene by 13.22%, improving the diversity of carbon-fixing microbiota. In addition, biochar also inhibited the relative abundances of pyruvate dehydrogenase (PDH), isocitrate dehydrogenase (IDH), and alpha-ketoglutarate dehydrogenase (A_KGD) at the late stage of composting, thereby reducing the CO2 release by 16.77%. Bamboo biochar also decreased the abundance of Methyl coenzyme-M reductase (MCR), which in turn reduced methane (CH4) release. Redundancy analysis (RDA) showed that Proteobacteria was the dominant phylum in the compost system during the cooling and maturity periods, which dominated the release of CO2 and was positively correlated with PDH, IDH, and A_KGD (p < 0.01). In addition, RubisCO was negatively correlated with organic matter (OM), CO2, CH4 (p < 0.01). Taken together, biochar can inhibit the activity of CO2-releasing microorganisms, thereby reducing carbon loss in composting. [ABSTRACT FROM AUTHOR]

Denitrification is an essential cause of nitrogen loss during composting. Therefore, to reveal the effect of bamboo biochar addition on nitrous oxide (N2O) emission and nitrogen fixation, this study analyzed changes in nitrogen transformation, nitrogen function genes and microbial communities by metagenomics technology, and explored their relationship with N2O emission. The results demonstrated that compared with the control group (C), the N2O emission of the experimental group (B) was significantly reduced, and the contents of nitrate nitrogen (NO3−-N) and total Kjeldahl nitrogen (TKN) were increased by 15.4% and 0.11%, respectively. Metagenomics analysis revealed that the abundances of napA and norB genes decreased by 26.9% and 22.44%, respectively, while nitrogen-fixing genes (nifK, nifD and nifH) increased by 46.9%, 60%, and 11.5%, respectively, during the thermophilic period. Redundancy analysis (RDA) showed that the emission of N2O is proportional to the content of NO3−-N and ammonium nitrogen (NH4+-N). Denitrification genes were proportional to Proteobacteria, while nitrogen fixation genes were positively correlated with Firmicutes. Furthermore, at the end of composting, the abundance of Luteimonas in denitrifying microbes in group B decreased by 7.45%, while the abundance of Frankia in nitrogen-fixing microbes increased by 27.52%. Therefore, the addition of biochar can enhance microbial nitrogen sequestration, thereby reducing nitrogen loss. [ABSTRACT FROM AUTHOR]

Composting is a process that converts organic materials including solid wastes into humus-like substances. Additives play an important role in regulating composting performances. This work investigated the influences of flue gas desulphurization gypsum (FGDG) on the properties and evolution of dissolved organic matter (DOM) during the co-composting of dairy manure, sugarcane leaf and pressmud (the sludge from sugar factory effluent) with the combination techniques of elemental analysis, particle size, zeta potential, UV–Vis spectroscopy and FT-IR technology. The results revealed that FGDG amendment reduced carbon loss and facilitated nitrogen emission in compost DOM, increased the aromaticity of DOM and compost maturity, enhanced the absorbance of –OH, –CHO, –COOH and C–O in polysaccharides. Additionally, the adding of FGDG was an inhibitive factor to the whole bacterial diversity during composting. These findings provided new insights into the evolution and properties of DOM and the microbial community during the composting process with FGDG amendment. [ABSTRACT FROM AUTHOR]

Antibacterial photodynamic therapy (APDT) is an encouraging therapy modality for bacterial infection. In this work, trithiophene aldehyde (3T‐CHO) as a new photosensitizers was isolated from Herba Ecliptae, and tryptophan (Trp) modified 3T‐CHO improve water solubility and reduced phototoxicity. The photosensitizer‐loaded vesicles were incorporated into a gel scaffold to obtain a wound dressing with detection and antibacterial function. Detection of the presence of pathogenic bacteria, such as Pseudomonas aeruginosa, based on the fluorescence signals was highly efficient and sensitive. The cytotoxin produced by the pathogenic bacteria to induce vesicle lysis, thereby the photosensitive antibacterial agent was released from the vesicle to realize the simultaneous intelligent detection and treatment of pathogenic bacteria. Compared with traditional dressings coated with antibiotics, the synthesized dressing avoids the drawback of pathogenic bacteria developing drug resistance. The proposed microbiologically responsive wound dressing could be used as a general methodology for the design and fabrication of bacterium‐responsive functional biomaterials. [ABSTRACT FROM AUTHOR]

The ensemble system PyH-SBA-15-Cu2+ was obtained via coordination interaction of pyrene derivative-functionalized mesoporous SBA-15 and Cu2+, and applied for the selective and sensitive detection of H2S over pH 6.0–12.0 in aqueous media. The sensing strategy was designed on the basis of the H2S-induced dissolution of Cu2+ from PyH-SBA-15-Cu2+. Cu2+ has good binding affinity to N atoms in PyH-SBA-15; therefore, the organic–inorganic hybrid ensemble PyH-SBA-15-Cu2+ was formed, which is nonfluorescent in aqueous solution because of the Cu2+-promoted emission quenching of PyH-SBA-15. The addition of H2S induces the dissolution of PyH-SBA-15-Cu2+ by the formation of stable CuS, thereby producing fluorescence revival of PyH-SBA-15. The correlative "turn-on" fluorescence signals of this ensemble system are linearly proportional to [H2S] in the concentration region of 0–1.0 × 10−4 M, showing a low detection limit of 3.7 × 10−7 M. Other common anions do not induce distinct fluorescence changes. When using the fluorescence intensity signal changes of PyH-SBA-15 as outputs and Cu2+ and S2− as inputs, PyH-SBA-15 can act as an XNOR logic gate. [ABSTRACT FROM AUTHOR]

This investigation was carried out on the effects of compost-born thermophilic complex microbial consortium (TCMC) composed of Ureibacillus suwonensis (TB42), Geobacillus thermodenitrificans (TB62) and Bacillus licheniformis (TA65) on co-composting of dairy manure and sugarcane leaves. The study assessed the TCMC influence on physicochemical parameters and dissolved organic matter (DOM) properties. Compared to the control (CP), the inoculated pile (CPT) showed a longer thermophilic phase, a faster organic matter degradation, a better Kjeldahl nitrogen preservation as well as a greater aromaticity and stability of DOM. Consequently, the inoculation with TCMC agent was effective in reducing the loss of nitrogen and accelerating maturity of compost. [ABSTRACT FROM AUTHOR]

Dissolved organic matter (DOM) is a crucial indicator of compost maturity and stability. Different pools of DOM fractions may function distinctly from one another and show unique properties in the transformation of organic matter and microbial activity. In this work, compost DOM was fractionated and the properties of individual DOM fractions including humic acids (HA), fulvic acids (FA) and hydrophilic compounds (Hi) were analyzed. The pools of HA, FA and Hi were studied via elemental analysis, FTIR and UV-Vis spectroscopy, and colloidal properties like particle size and zeta potential were characterized as well. Compared to HA or FA, Hi pool had a higher content of nitrogenous compound, higher saturated degree and more easily oxidized capacity. As composting proceeded, the aromaticity of HA and FA was higher and higher while Hi exhibited only a very slight change. The colloidal analysis indicated that the particle size of DOM subfractions gradually decreased. Hi compounds from matured compost had a good application potential in cations absorption. Taken together, these results provide valuable insights into the evolution and characteristics of DOM fractions during a composting process of dairy manure and Chinese herbal residues. [ABSTRACT FROM AUTHOR]

Composting is an effective method in treating solid organic wastes, in which dissolved organic matter (DOM) plays an important role in transformation of organic matter and microbial activity. Therefore, an understanding of the properties and evolution of DOM during composting is crucial. In this study, DOM was studied using elemental analysis, spectroscopic analysis (UV-vis, FTIR, and pyrolysis-GC/MS), and colloidal analysis during a 120-day composting. Results showed that the content of N and O in DOM increased while C and H content declined progressively over the composting time. Aliphatic C-H stretching, aromatic C=C or C=O stretching of amide groups, and C-O stretch (carbohydrates) showed an obvious decrease, while COO- and C-N groups had a significant increase. The evolution of DOM indicated a gradual decrease of the lipid and polysaccharide fractions, whereas an increase of aromatic and nitrogenous compounds was observed. The DOM also showed a more stable status, and an accumulation of small molecular compounds occurred with composting proceeded. Taken together, these results shed a good insight into the properties and evolution of DOM during a composting process. [ABSTRACT FROM AUTHOR]

The differences of the physical and chemical parameters in the samples from the processes of anaerobic digestion (AD), aerobic composting (AC) and the residue after anaerobic digestion for aerobic composting (RAC) were comparatively investigated in this study. At the same time the quantities and structural characteristics of bacteria were studied by PCR-DGGE. The results showed that in the three ways for treating solid organic wastes, AC process had the most intensive decomposition of organic matter, with degradation rate of 51.51 %. The significant differences in temperature, pH and ammonia nitrogen (NH -N) content were observed in these treatments. The microbial species of Bacillus mainly existed in the process of AD while the Proteobacteria and Firmicutes primarily occurred in AC and RAC. AC has the most abundant biodiversity while the biological diversity of RAC is relatively single. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of adding flue gas desulphurization gypsum (FGDG) on the transformation and fate of nitrogen during co-composting of dairy manure and pressmud of a sugar refinery. The ammonia absorption of FGDG was investigated. The changes in compost temperature, pH, electrical conductivity (EC), moisture, organic matter, the C/N ratio, Kjeldahl N, NH4+-N, NO2−-N, NO3−-N were assessed. The addition of FGDG did not significantly affect compost temperature, pH, EC, moisture, and organic matter degradation. However, the addition of FGDG significantly increased the NH4+-N content in the compost during the thermophilic phase, and the NH4+-N maximal content in the compost with FGDG (CP+G) was 59.9% more than that in the compost without FGDG (CP–G). FGDG was thought to create the formation of (NH4)2SO4and the cation exchange between NH4+and Ca2+. The NO2−-N content in the CP+G peaked on day 15, and was not observed in the CP–G. In the final compost products, the NO3−-N concentration in the CP–G was more than that in the CP+G, which was 1451 (CP–G) and 1109 mg·kg−1(CP+G) dry material. This might be due to the NO2−accumulation in the CP+G, which accelerated N loss in the form of N2O. There is a strong correlation between N2O emission and NO2−-N accumulation in the composting process. Compared with the original N content in the compost mixture, the N loss in CP–G and CP+G were 15.0 and 10.8%, respectively. These results revealed that NH4+-N conservation effect was improved during the thermophilic phase and the total N loss was mitigated by adding FGDG into composting materials. FGDG could be utilized as a potential amendment to conserve nitrogen during composting. [ABSTRACT FROM PUBLISHER]

Eu-doped CaZrO phosphor with perovskite-type structure was synthesized by the high temperature solid-state method. The samples were characterized by X-ray diffraction, scanning electron microscopy, fluorescence spectrophotometer and UV-vis spectrophotometer, respectively. XRD analysis showed that the formation of CaZrO was at the calcinations temperature of 1400°C. The average diameter of CaZrO with 4 mol% doped-Eu was 2µm. The PL spectra demonstrated that CaZrO:Eu phosphor could be excited effectively in the near ultraviolet light region (397 nm) and emitted strong red-emission lines at 616 nm corresponding to the forced electric dipole D → F transitions of Eu. Meanwhile, the light-emitting diode was fabricated with the CaZrO:Eu phosphor, which can efficiently absorb ∼ 400 nm irradiation and emit red light. Therefore CaZrO:Eu may have applications for a near ultraviolet InGaN chip-based white light-emitting diode. [ABSTRACT FROM AUTHOR]

Static and stirred culture systems are widely used to expand hematopoietic cells, but differential culture performances are observed between these systems. We hypothesize that these differential culture outcomes are caused by the physiological responses of CD34+ hematopoietic stem and progenitor cells (HSPCs) to the different physical microenvironments created in these culture devices. To understand the genetic changes provoked by culture microenvironments, the gene expression profiling of CD34+ HSPCs grown in static and stirred culture systems was compared using SMART-PCR and cDNA arrays. The results revealed that 103 and 99 genes were significantly expressed in CD34+ cells from static and stirred systems, respectively. Of those, 91 have similar levels of expression, while 12 show differential transcription levels. These differentially expressed genes are mainly involved in anti-oxidation, DNA repair, apoptosis, and chemotactic activity. A quantitative molecular understanding of the influences of growth microenvironments on transcriptional events in CD34+ HSPCs should give new insights into optimizing culture strategies to produce hematopoietic cells. [ABSTRACT FROM AUTHOR]