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Xylose is the second most abundant carbohydrate present in nature, while its inefficient utilization severely restricts the economic viability of lignocellulosic biomass-based biorefinery. Herein, metabolic engineering strategies involving xylose metabolism and the succinic acid (SA) synthetic pathway were developed in Yarrowia lipolytica for the production of SA from lignocellulosic hydrolysate. First, the Ylsdh5 gene (succinate dehydrogenase subunit 5) was inactivated in Y. lipolytica BZ, which can grow on xylose as the sole carbon source, thereby obtaining a strain capable of synthesizing SA from xylose. Subsequently, the glucose–xylose assimilating rate and SA titers were further optimized by blocking the by-product pathway and enhancing the SA synthetic pathways. Then, with the overexpression of the crucial mitochondrial dicarboxylic acid transporter YlDic, the obtained SA producer Y. lipolytica BDic5 showed excellent xylose assimilation performance, which could utilize all the glucose and xylose in either pure culture or hydrolysate fermentation. Remarkably, BDic5 exhibited robust growth in 30% solid-loading of corn stover hydrolysate without hydrolysate detoxification or dilution, and the fermentation process did not require neutral pH maintenance. Finally, up to 105.42 g L−1 SA was produced from undetoxified lignocellulosic hydrolysate using the fed-batch strategy in a 3 L bioreactor, which was the highest SA titer achieved from lignocellulosic feedstock to date. Following downstream purification of the acidic fermentation broth, 61.75% of the total SA with purity of 92.81% was recovered. These promising results indicated that the recombinant strain exhibited great potential for bioconversion of lignocellulosic biomass into bio-SA, which demonstrated great prospects for industrial production. [ABSTRACT FROM AUTHOR]

Fusobacterium gonidiaformans is an anaerobic Gram-negative bacillus rarely reported as a cause of human infection. We recently dealt with a woman with fever in whom this pathogen was isolated in pure culture in blood cultures in pure culture. We have also searched the literature for all cases of this disease. [ABSTRACT FROM AUTHOR]

• Rf-GAC+ M.barkeri obtained the maximum methane yield of 0.345 ± 0.02 L(stp)/g COD. • AD process was stable at OLR of 17.5 kg COD/(m³·d) in the presence of RF-GAC. • Solely adding RF-GAC enriched Methanothrix to maintain stability at high OLR. • The presence of Rf-GAC increased COD removal efficiency by 14 % and reached 97 %. • Adding M.barkeri weakened Methanothrix but still enhanced methane production. Effective treatment of high-concentration brewery wastewater through anaerobic digestion (AD) has always been a challenging issue. Enhancing direct interspecies electron transfer (DIET) was demonstrated to increase methane production during AD under high organic loading rate (OLR). Herein, the feasibility of enhancing DIET with the addition of riboflavin-loaded granular activated carbon (RF-GAC) as well as co-addition with Methanosarcina barkeri (Rf-GAC+ M.barkeri) was investigated (M.barkeri is well-known to be capable of DIET with electroactive bacteria). During the whole process, the Rf-GAC and the Rf-GAC+ M.barkeri group both achieved average COD removal rates above 97 %, which was 14 % higher than that of the control. The average methane production in the Rf-GAC group and the Rf-GAC+ M.barkeri group respectively reached 0.334 ± 0.02 L(stp)/g COD and 0.345 ± 0.02 L(stp)/g COD, 1.35 and 1.39 times higher than the 0.247 ± 0.03 L(stp)/g COD reached by the control. The control reactor deteriorated at an OLR of 12 kg COD/(m3·d), whereas the Rf-GAC and the Rf-GAC+ M.barkeri group maintained stable as the OLR reached as high as 17.5 kg COD/(m3·d) and the volatile fatty acids concentration was consistently below 10 mM. The RF-GAC performed better than Rf-GAC+ M.barkeri in enriching Methanothrix , whose relative abundance was 60.6 % in the former group. Metabolic pathway analysis revealed the addition of RF-GAC upregulated genes related to DIET in Methanothrix species, including hdrA and fpoD. Furthermore, Methanothrix remained the dominant archaea even continuously inoculating pure strains of M.barkeri during the entire operational period. Pure culture experiments proved that GAC inhibited M.barkeri growth. The results of this study can be optimized for practical application of AD treating high-concentration brewery wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

• Community of weak electricigens enriched in saline bioelectrochemical system. • Halotolerant isolates characterised with chronoamperometry and voltammetry. • Micrococcus sp. YH-1 (8.29 μA/cm2) is comparable to reports of S. oneidensis. • Gordonia sp. RH-1 and Stutzerimonas sp. CH-1 are weak electricigens. • Cellular appendages seen in Micrococcus sp. YH-1 and Stutzerimonas sp. CH-1. Microbial electroactivity in elevated salt conditions is seldom studied, despite both fundamental and applied relevance. This work reports the enrichment of electroactive microorganisms under saline conditions (2 % NaCl), performed on screen-printed carbon electrodes with applied anodic potential. From the weakly electroactive enriched community, three halotolerant electroactive isolates were obtained in pure culture and identified via 16S rRNA gene sequencing. Two isolates were Gram positive (proposed names Micrococcus sp. YH-1 and Gordonia sp. RH-1) and one was Gram negative (proposed name Stutzerimonas sp. CH-1). The isolates were electrochemically characterised on conventional carbon felt electrodes using chronoamperometry. After two days of growth, a current density of 8.29 ± 0.85 μA/cm2 was observed in Micrococcus sp. YH-1, comparable to reported values for the model electroactive microorganism Shewanella oneidensis. Gordonia sp. RH-1 and Stutzerimonas sp. CH-1 appeared to be weak electricigens due to their low current output (2.19 ± 0.46 μA/cm2 and 1.73 ± 0.47 μA/cm2, respectively). The isolates are notable as there are very limited reports of electroactivity in the genera Micrococcus and Gordonia. Cyclic voltammetry revealed prominent redox peaks in Micrococcus sp. YH-1 and Stutzerimonas sp. CH-1. Scanning electron microscopy demonstrated colonisation of the electrode by each isolate, along with thin cellular appendages in Micrococcus sp. YH-1 and Stutzerimonas sp. CH-1. This work extends the catalogue of characterised halotolerant electroactive microbes while also enhancing our understanding of weak electricigens, extracellular electron transfer in Gram positives, and the inherent electroactivity of the natural environment. [Display omitted] [ABSTRACT FROM AUTHOR]

• Nano-magnetite incorporation enriched DIRB in sewage. • Nano-magnetite built coherent conductive pathways to promote vivianite recovery. • Nano-magnetite stimulated the secretion of humic acids in EPS. • Nano-magnetite improved the communication between DIRB and electron acceptors. Acting as both terminal and conductor of extracellular electron transfer (EET), little studies were focused on how nano-magnetite participated in the dissimilated iron reduction (DIR), especially the synthesis of vivianite, which was the typical DIR products from sewage. In this study, nano-magnetite was confirmed to enhance DIR of ferrihydrite and akaganeite for vivianite recovery from sewage. Nano-magnetite incorporation enriched Comamonas and Geobacter in sewage, and microbial protein content was increased by 123 % and 57 % in ferrihydrite and akaganeite batches, respectively. In Geobacter sulfurreducens PCA pure culture, vivianite yield was promoted by 21 % and 37 % in ferrihydrite and akaganeite batches in the presence of nano-magnetite, respectively. Due to its nanoscale size and superior electrical conductivity, nano-magnetite embedded in the gaps formed by the microorganisms and electron acceptor, and architected coherent conductive pathways to promote EET. Simultaneously, the addition of nano-magnetite stimulated the secretion of proteins, polysaccharides, and humic acids in the extracellular polymeric substances. Nano-magnetite addition structured an enormous and compact electron transfer network, thus enhanced DIR and vivianite formation. Our study proposed a new strategy to promote iron-reduction-coupled phosphorus recovery with natural DIR products, and provided theoretical support for clarifying the interaction between minerals and microorganisms. [Display omitted] [ABSTRACT FROM AUTHOR]

Nitrogen pollution poses a substantial threat to water bodies, making the exploration of effective treatment technologies imperative. Among these, biological denitrification stands out as one of the most efficient methods. Various materials, including biochar, graphene, carbon nanotubes, and nanoparticles, have gained widespread use across different industries due to their unique properties. Numerous studies have investigated the impact of these materials on microbial denitrification individually, focusing on their influence on key enzymatic processes, functional genes, electron transport, functional proteins, and microbial metabolic activities. This manuscript aims to contribute a comprehensive and holistic perspective by presenting consolidated data on the collective impact of biochar, graphene, carbon nanotubes, and nanoparticles on microbial denitrification. The combination of biochar and microorganisms improves denitrification performance by 415%. Graphene increases enzyme activity (100–175.4%). The coupling of carbon nanotubes and microorganisms reduced denitrification performance by 57.42%. Nanoparticles reduce denitrification performance (73.4%), enzyme activity (63%), and electron transfer rate (52.4%) by entering the cell membrane. Moreover, these materials have been observed to induce alterations in the community structure of microorganisms involved in denitrification. The manuscript delves into the intricate details of how these materials influence the conformational changes of denitrifying enzymes, emphasizing the relationship between enzyme activity and structural modifications. Overall, this manuscript not only provides a thorough analysis of the effects of biochar, graphene, carbon nanotubes, and nanoparticles on microbial denitrification but also explores their implications for the conformational dynamics of denitrifying enzymes. Furthermore, it outlines avenues for future research, offering a roadmap to guide upcoming studies in this critical field. [ABSTRACT FROM AUTHOR]

Dissimilatory iron reduction (DIR) is an important form of microbial respirations and a key part of iron biogeochemical cycle. A wide range of both bacteria and archaea that can conserve energy through Fe(III) reduction are called dissimilatory iron-reducing microorganisms (DIRMs). They have been increasingly recognized as important for coupling organic carbon oxidation in diverse anaerobic environments, such as soil, sediments, freshwater, marine water as well as extreme environments. In parallel with their phylogenetic diversity, DIRMs possess metabolic versatility, including multiple extracellular electron transfer (EET) pathways and various electron donors as well as acceptors. In this review, phylogenetic, environmental distribution of DIRMs was demonstrated comprehensively by summarizing 51 isolated DIRMs belonging to 27 genera in previous literature. EET mechanisms were further elaborated on based on four DIRMs representatives: Geobacter, Shewanella, Gram-positive bacteria and archaea. Various electron donors, acceptors, and novel metabolisms revealed recently prompt the development of DIRMs biotechnological applications, including bioleaching, bioremediation, biosynthesis, anaerobic fermentation, and production of bioelectricity. Although past decades have witnessed a great increase of the publications in DIRMs, further investigation are required for deep understanding and practical applications, such as their roles in natural environments, EET mechanisms in different DIRMs, cooperation with other microbes, and mechanisms of improved bioproduction by adding iron-oxides. DIRMs in real world. (1) they can be used for bioleaching; (2) they can be used for bioremediation for heavy metals and organic pollutants; (3) in aquatic environments, they can conduct iron reduction and form iron precipitate; (4) they can be used to produce current; (5) they can synthesize bioproducts; (6) they can form stable network with other soil microorganisms; (7) in various environments, they can form microbial iron cycle with iron-oxidizing microorganisms and influence many processes. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial strain that induces infections and exhibits resistance to most standard medications, complicating treatment efforts. MRSA infections pose a significant challenge, particularly for those with diabetic foot infections, frequently resulting in hospitalisation and, in some cases, amputation of the affected leg. To address this issue, we concentrated on synthesising carbon nanospheres (CNS) utilising a technique known as probe ultrasonication. These tiny particles exhibit biocompatibility and possess antimicrobial characteristics. Due to their small size and extensive surface area, CNS can penetrate the bacterial cell wall and carry medications more efficiently. We examined and analysed the CNS using several methodologies like XRD, Raman, FTIR, zeta potential, TEM and SEM to comprehend its structure and characteristics. We also examined their efficacy against MRSA bacteria at several dosages. The findings indicate that CNS may serve as an effective intervention for MRSA infections in diabetic foot ulcers, thereby decreasing the necessity for hospitalisation or amputations. [ABSTRACT FROM AUTHOR]

Collagen films play an essential role in guided bone-regeneration (GBR) techniques, which create space, promote cell adhesion, and induce osteogenic differentiation. It is therefore crucial to design appropriate GBR films to facilitate bone regeneration. However, current electrospun collagen scaffolds used as bioactive materials have limited clinical applications due to their poor mechanical properties. In this study, polyvinyl alcohol (PVA)/collagen (Col) films were electrospun by mixing PVA and type I collagen solution. For the first time, the intrafibrillar mineralization of aragonite nanocrystals within the PVA/Col fibrils was achieved, resulting in the formation of a hierarchical, bioactive film. The PVA/Col–CaCO3 film exhibited good mechanical properties, with hardness and Young's modulus values of 211.6 ± 0.1 MPa and 5.6 ± 1.7 GPa, respectively. Furthermore, bone marrow mesenchymal stem cells (BMSCs) inoculated onto the PVA/Col–CaCO3 film demonstrated robust adhesion and proliferation. The mineralized fibrils effectively stimulated the growth of BMSCs while suppressing cell apoptosis. Besides, the PVA/Col–CaCO3 film significantly induced the osteogenic differentiation of BMSCs, revealing its potential biomedical applications in hard tissue engineering. [ABSTRACT FROM AUTHOR]

Human hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) are the major stem cells of the bone marrow and are usually isolated from the peripheral blood. In the present study, we isolated these stem cells by an apheresis method from a donor who was administered granulocyte colony-stimulating factor (G-CSF). In vitro propagation of these stem cells showed a plastic-adherence property expressing CD73 and CD105 surface markers, which is a characteristic feature of MSCs. HSCs are non-adherent cells growing as a suspension culture, expressing CD150, CD133, CD34, and CD45 on their surface, which regulate the quiescence nature, and they derive energy from anaerobic glycolysis. The HSCs grow slowly compared to MSCs, are more viable, and survive for long periods under in vitro conditions, which are due to the expression of telomerase, BCL2, and Notch1 genes. The poor viability of MSCs in the culture due to the prominent expression of apoptotic genes BAX, caspase-3, and caspase-9 leads to rapid apoptosis. This was evident even in cells (astrocytes, osteocytes, and beta cells of the islets of Langerhans) differentiated from HSCs and MSCs, thus highlighting the importance of HSCs, the naive stem cells, in regeneration of tissues. [ABSTRACT FROM AUTHOR]

Bacillus is a ubiquitous soil bacterium for its plant growth-promoting properties, and it is widely used as a biofertilizer. This research aimed to isolate and determine the morphology and biochemical properties associated with plant-growth promotion ability characterizing Bacillus strains. The bacteria were isolated from the rhizosphere of various highland vegetables grown in Andisols soil in Indonesia. Bacillus isolation was conducted using the serial dilution plate method by means of tryptic soy agar. Characterization of the isolated bacteria included Gram staining, biochemical characteristics, pathogenicity testing, and the production of metabolites, including organic acids, phytohormones, and exopolysaccharides. Four bacterial isolates were identified as Bacillus based on colony and cell morphology, the presence of endospore, as well as biochemical properties and metabolite production. The species determination by PCR amplification and 16S rRNA gene sequence analysis revealed that the four Bacillus were identified as Bacillus safensis strain MDL5, Bacillus altitudinis strain RPW2, and Bacillus sp. strain SZ057. The study presents the occurrence of Bacillus within the rhizosphere of vegetables and the understanding of their properties being considered for biofertilizer development. [ABSTRACT FROM AUTHOR]

This research was conducted with the aim of providing a chicken supply chain model based on challenges, success factors and human resource limitations. The information required for the research was collected from 15 experts and managers of poultry farms of Behparvor Group in the whole country and their opinions were obtained through interpretive structural modeling (ISM) interviews with a qualitative approach. In this research, using interpretive structural modeling, an integrated model for the chicken supply chain based on challenges, success factors and human resource limitations was designed. The results of interpretative structural modeling in this research showed the challenges of human resources with the dimensions of not paying attention to employee training, competitors' attempts to attract the company's experts, the nature of hard work, the inability to retain the company's experts, employees' resistance to change and leaving the job. Expert employees of the company as negative factors of the optimal supply chain of chicken production and also, the success factors of human resources with the dimensions of employee training, employee empowerment, employee welfare, job justice, financial justice and attracting and retaining employees as positive factors of the optimal supply chain of chicken production, along with the limitations of human resources with the dimensions of the lack of specialized labor in the labor market, the supply of labor by non-specialists and the lack of financial resources to attract specialized labor as negative factors of the optimal supply chain of chicken production constitute the integrated model of the chicken supply chain based on human resources. [ABSTRACT FROM AUTHOR]

The need for energy resources is continuously increasing worldwide and raises the need for environmentally benign, low-cost processes for energy generation. Membraneless microbial fuel cell (ML-MFC) has emerged as a promising solution for electricity production. MFCs are bioelectrical devices that harness the metabolism of electrogenic bacteria (EB) for generation of electrical energy. In the present investigation, Bacillus subtilis (BS) and Pseudomonas aeruginosa (PA) were utilized to catalyze transformation of carbon sources in chicken manure as source of renewable energy. The study was carried out by setting the experimental conditions with the ambient temperature (34°C ± 1°C) pH (12), electrode distance (3 cm), initial moisture amount (57% vol/wt) set as constant. Results highlighted BS and PA performance in an ML-MFC system for 7 to 14 days incubation periods. The specific growth recorded 0.0262 g(Lh−1) BS strain and 0.0141 g(Lh−1) PA strain for 7 days and the specific growth 0.0057 g(Lh−1) BS strain and 0.00163 g(Lh−1) PA strain was recorded after 14 days incubation. ML-MFCs were conducted for 14 days incubation period and significant effect of growth of BS and PA were reflected on voltage and power production. Maximum voltage (BS, 0.06 V; PA, 0.043 V) and power density (BS, 391 mW/m2; PA, 591 mW/m2) were recorded after 14 days of incubation. A series of ML-MFC contributed a promising performance for BS, which was 0.05 V and 9.05 mW/m2, compared with PA, which was 0.022 V and 9.05 mW/m2. Moreover, reduction in macronutrients and micronutrients was analyzed through inductively coupled plasma-optical emission spectroscopy (ICP-OES), chemical oxygen demand (COD) removal, and Fourier-transform infrared spectroscopy (FTIR) analysis. Thus, analysis on scanning electron microscope (SEM) and FTIR bands showed that these two strains are compatible for biofilm formation and degradation of the chicken manure into simple bands. The study concluded that BS showed better performance in terms of EB growth (21.7%; 14 days), COD removal (2.1%; 14 days), and power density generation (54.7%; 14 days) as compared with the PA strain. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: In recent years, there has been an increased need to reduce chemical pollutants, and studies of entomopathogenic fungi, which are natural regulators for several harmful insects, has become widespread. Entomopathogenic fungi are inexhaustible source of natural strains that have a broad range of virulence in many species of harmful insects. Among entomopathogenic anamorphic ascomycetes, those fungi from the genus Beauveria are most studied. Studies have been conducted for the past two hundred years, meaning that most mycoinsecticides are based on the results of these studies. Although these fungi are considered well-studied, research into the cryptic species composition of genus Beauveria and their geographical distribution remains relevant for identifying promising strains for pest control. This study aims to investigate the biodiversity of the genus Beauveria prevalent in the soils of southern Kazakhstan (Turkestan region). METHODS: Entomopathogenic fungi of the genus Beauveria are widespread in the natural ecosystem, including soil. Therefore, during 2023-2024 soil samples from various locations in southern Kazakhstan (Turkestan region) were collected to isolate entomopathogenic fungi. The insect bait method was used to isolate entomopathogenic fungi. Larvae of Tenebrio molitor (Coleoptera: Tenebrionidae) were used as baits, with five replicates per sample, and placed in soil samples inside plastic containers. After infection, dead larvae were transferred to a moist chamber to promote mycosis development. Fungal conidia were then transferred to Sabouraud’s agar medium. Species identification of the isolated fungi was conducted using classical light microscopy and molecular genetic analysis of internal transcribed spacer regions and the translation elongation factor 1 alpha gene.FINDINGS: 41 isolates were isolated into pure culture, of which 36 were fully identified. Polymerase chain reaction analysis of the translation elongation factor 1-alpha gene revealed that all isolates belong to Beauveria bassiana. However, analysis of the internal transcribed spacer region identified two cryptic species within the genus Beauveria: Beauveria bassiana and Beauveria pseudobassiana. The majority of the isolates were identified as Beauveria bassiana – 84 percent (31 isolates), while Beauveria pseudobassiana accounted for 16 percent (5 isolates).CONCLUSION: The species composition of entomopathogenic fungi in the soils of southern Kazakhstan (Turkestan region) turned out to be quite modest and sparse, which explains the soil and climatic conditions of the region. A distinctive feature of the climate of the study region is aridity. Only fungi of the genus Beauveria were isolated, which are considered cosmopolitan. Isolation of viable entomopathogenic fungi demonstrates adaptation to arid conditions, which is very important in the context of climate change.

This article provides a comprehensive review and sequence-structure analysis of transcription regulator (TR) families, TetR and OmpR/PhoB, involved in specialized secondary metabolite (SSM) biosynthesis and resistance. Transcription regulation is a fundamental process, playing a crucial role in orchestrating gene expression to confer a survival advantage in response to frequent environmental stress conditions. This process, coupled with signal sensing, enables bacteria to respond to a diverse range of intra and extracellular signals. Thus, major bacterial signaling systems use a receptor domain to sense chemical stimuli along with an output domain responsible for transcription regulation through DNA-binding. Sensory and output domains on a single polypeptide chain (one component system, OCS) allow response to stimuli by allostery, that is, DNA-binding affinity modulation upon signal presence/absence. On the other hand, two component systems (TCSs) allow cross-talk between the sensory and output domains as they are disjoint and transmit information by phosphorelay to mount a response. In both cases, however, TRs play a central role. Biosynthesis of SSMs, which includes antibiotics, is heavily regulated by TRs as it diverts the cell's resources towards the production of these expendable compounds, which also have clinical applications. These TRs have evolved to relay information across specific signals and target genes, thus providing a rich source of unique mechanisms to explore towards addressing the rapid escalation in antimicrobial resistance (AMR). Here, we focus on the TetR and OmpR family TRs, which belong to OCS and TCS, respectively. These TR families are well-known examples of regulators in secondary metabolism and are ubiquitous across different bacteria, as they also participate in a myriad of cellular processes apart from SSM biosynthesis and resistance. As a result, these families exhibit higher sequence divergence, which is also evident from our bioinformatic analysis of 158 389 and 77 437 sequences from TetR and OmpR family TRs, respectively. The analysis of both sequence and structure allowed us to identify novel motifs in addition to the known motifs responsible for TR function and its structural integrity. Understanding the diverse mechanisms employed by these TRs is essential for unraveling the biosynthesis of SSMs. This can also help exploit their regulatory role in biosynthesis for significant pharmaceutical, agricultural, and industrial applications., (© 2023 Wiley Periodicals LLC.)