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International Journal of Systematic and... Jun 2024Reductive soil disinfestation (RSD), also known as biological soil disinfestation, is a bioremediation method used to suppress soil-borne plant pathogens by stimulating...
Reductive soil disinfestation (RSD), also known as biological soil disinfestation, is a bioremediation method used to suppress soil-borne plant pathogens by stimulating the activity of indigenous anaerobic bacteria in the soil. An anaerobic bacterial strain (E14) was isolated from an anoxic soil sample subjected to RSD treatment and then comprehensively characterized. Cells of the strain were Gram-stain-positive, curved to sigmoid, and spore-forming rods. Cells were motile with a polar flagellum. Strain E14 grew in peptone-yeast extract broth, indicating that it utilized proteinous compounds. Strain E14 was also saccharolytic and produced acetate, isobutyrate, butyrate, isovalerate and gases (H and CO) as fermentation products. The strain did not decompose any of examined polysaccharides except for starch. The major cellular fatty acids of strain E14 were iso-C and iso-C DMA. The closest relative to strain E14, based on 16S rRNA gene sequences, was SYSU GA15002 (96.2 %) in the . Whole-genome analysis of strain E14 showed that its genome was 4.66 Mb long with a genomic DNA G+C content of 32.5 mol%. The average nucleotide identity (ANIb) between strain E14 and SYSU GA15002 was 69.0 %. The presence of the genes encoding glycolysis and butyrate production via the acetyl-CoA pathway was confirmed through genome analysis. Based on the obtained phylogenetic, genomic and phenotypic data, we propose that strain E14 should be assigned to the genus in the family as sp. nov. The type strain is E14 (=NBRC 115133=DSM 114974).
Topics: Base Composition; RNA, Ribosomal, 16S; Soil Microbiology; Phylogeny; Clostridium; DNA, Bacterial; Fatty Acids; Bacterial Typing Techniques; Sequence Analysis, DNA; Genome, Bacterial; Anaerobiosis; Biodegradation, Environmental
PubMed: 38861306
DOI: 10.1099/ijsem.0.006412 -
Journal of Environmental Management Jul 2024Waste activated sludge (WAS) and meat processing waste (MPW) were acted as co-substrates in anaerobic co-digestion (AcD), and biochemical methane potential (BMP) test...
Waste activated sludge (WAS) and meat processing waste (MPW) were acted as co-substrates in anaerobic co-digestion (AcD), and biochemical methane potential (BMP) test was carried out to investigate the methane production performances. Microbial community structure and metabolic pathways analyses were conducted by 16S rRNA high-throughput sequencing and functional prediction analysis. BMP test results indicated that AcD of 70% WAS+30% MPW and 50% WAS+50% MPW (VS/VS) could significantly improve methane yield to 371.05 mL/g VS and 599.61 mL/g VS, respectively, compared with WAS acting as sole substrate (191.87 mL/g VS). The results of microbial community analysis showed that Syntrophomonas and Petrimonas became the dominant bacteria genera, and Methanomassiliicoccus and Methanobacterium became the dominant archaea genera after MPW addition. 16S functional prediction analysis results indicated that genes expression of key enzymes involved in syntrophic acetate oxidation (SAO), hydrogenotrophic and methylotrophic methanogenesis were up-regulated, and acetoclastic methanogenesis was inhibited after MPW addition. Based on these analyses, it could be inferred that SAO combined with hydrogenotrophic and methylotrophic methanogenesis was the dominant pathway for organics degradation and methane production during AcD. These findings provided systematic insights into the microbial community changes and metabolic pathways during AcD of WAS and MPW.
Topics: Sewage; Anaerobiosis; Methane; Metabolic Networks and Pathways; RNA, Ribosomal, 16S; Bacteria; Meat; Archaea
PubMed: 38852403
DOI: 10.1016/j.jenvman.2024.121444 -
Environmental Monitoring and Assessment Jun 2024Herbal waste produced during the manufacturing of herbal products is a potential feedstock for anaerobic digestion due to high amount of organic matter that can be...
Herbal waste produced during the manufacturing of herbal products is a potential feedstock for anaerobic digestion due to high amount of organic matter that can be transformed into biogas as an energy resource. Therefore, the present study was undertaken to convert herbal waste produced during the manufacturing of common of Ayurveda products into biogas through anaerobic digestion process using batch test study under controlled mesophilic temperature conditions of 35 °C with food to inoculum ratio of 0.75. The maximum biomethane potential (BMP) of 0.90 (gCHCOD/g COD) and sludge activity of 0.70 (gCH-CD/gVSS) was exhibited by WS herbal waste owing to its high chemical oxygen demand (COD) of 4 g/g and better solubilization potential of the organic matter showing change in volatile suspended solids (ΔVSS) of 79%. On the other hand, the waste derived from the TA herb, exhibited the least biogas yield of 0.55 (gCHCOD/g COD) and sludge activity of 0.40 (gCH-CD/gVSS), albeit with higher organic matter present. This was due to the possible hindrance of waste solubilization by the presence of lignin. The waste derived from VVL and PE showed intermediate BMP and sludge activity. The methane generation rate constant (k), a key indicator of the biodegradation potential, was also evaluated. The k values showed similar trend as of BMP values ranging from 0.081 to 0.15 d thus indicating the influence of presence of lignin and the change in ΔVSS. The present study proves anaerobic digestion to be an alternative treatment method to be a milestone for management of herbal wastes and can be successfully implemented on real-scale systems.
Topics: Anaerobiosis; Biofuels; Methane; Biological Oxygen Demand Analysis; Sewage; Waste Disposal, Fluid; Bioreactors; Industrial Waste
PubMed: 38849696
DOI: 10.1007/s10661-024-12769-x -
Environmental Science and Pollution... Jun 2024As a crucial hydrolytic enzyme, urease plays a vital role in anaerobic biological treatment. It is well-known that manganese ions are abundant in landfill leachate, but...
As a crucial hydrolytic enzyme, urease plays a vital role in anaerobic biological treatment. It is well-known that manganese ions are abundant in landfill leachate, but their concentration fluctuates significantly. However, few studies have investigated the effect and mechanism of different concentrations of Mn on urease activity during anaerobic biological treatment of landfill leachate. This paper aimed to investigate the effects and mechanisms of different concentrations of Mn on urease activity. The results showed that an appropriate amount of Mn could significantly enhance urease activity, while a high concentration of Mn could inhibit it. Insight into the mechanisms behind this phenomenon, various methods such as Zeta potential, particle size, ultraviolet spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and statistical analysis were employed in our study. Research suggested that, on one hand, Mn may form hydrogen bonds with the side chain amino or carboxyl groups of urease amino acid residues, affecting the structure of urease through hydrogen bonding. Additionally, Mn also binds to urease through hydrophobic interactions. On the other hand, the C-OH and C-N functional groups in urease have a strong affinity for Mn, and changes in these functional groups can greatly enhance the activity of urease. Furthermore, under the action of high concentrations of Mn, while the structure of urease becomes more stable, there is also a steric hindrance phenomenon that affects the substrate from entering the catalytic center. Therefore, studying the mechanism of Mn affecting urease activity has significant biological significance and provides a new perspective for exploring the impact of metals on anaerobic bioprocessing of landfill leachate.
Topics: Urease; Manganese; Water Pollutants, Chemical; Anaerobiosis
PubMed: 38849617
DOI: 10.1007/s11356-024-33907-5 -
Microbial Pathogenesis Jun 2024Gut bacterial dysbiosis has been linked to several gastrointestinal diseases, including deadly colorectal cancer (CRC), a leading cause of mortality in cancer patients....
Gut bacterial dysbiosis has been linked to several gastrointestinal diseases, including deadly colorectal cancer (CRC), a leading cause of mortality in cancer patients. However, perturbation in gut bacteriome during colon cancer (CC, devoid of colorectal malignancy) remains poorly explored. Here, 16S rRNA gene amplicon sequencing was carried out for fecal DNA samples targeted to hypervariable V3-V4 region by employing MiSeq platform to explore the gut bacterial community shift in CC patients. While alpha diversity indices predicted high species richness and diversity, beta diversity showed marked gut bacterial compositional dissimilarity in CC versus healthy controls (HC, n = 10 each). We observed a significant (p < 0.05, Wilcoxon Rank-Sum test) emergence of low-abundant anaerobic taxa, including Parvimonas and Peptostreptococcus, in addition to Subdoligranulum, Coprococcus, Holdemanella, Solobacterium, Bilophila, Blautia, Dorea, Moryella and several unidentified taxa, mainly affiliated to Firmicutes, in CC patients. In addition, we also traced the emergence of putative probiotic taxon Slackia, belonging to Actinomycetota, in CC patients. The emergence of anaerobic Firmicutes in CC is accompanied by a significant (p < 0.05) decline in the Klebsiella, as determined through linear discriminant analysis effect size (LEfSe) and heat tree analyses. Shifts in core microbiome and variation in network correlation were also witnessed. Taken together, this study highlighted a significant and consistent emergence of rare anaerobic Firmicutes suggesting possible anaerobiosis driving gut microbial community shift, which could be exploited in designing diagnostic and therapeutic tools targeted to CC.
PubMed: 38848931
DOI: 10.1016/j.micpath.2024.106726 -
The Science of the Total Environment Sep 2024The low anaerobic digestion efficiency of the solid phase separated from pre-treated sludge indicates the need to explore other suitable resource utilization pathways...
The low anaerobic digestion efficiency of the solid phase separated from pre-treated sludge indicates the need to explore other suitable resource utilization pathways for sludge solid phase. However, there is a lack of comprehensive and in-depth research on the physicochemical properties of sludge solid phase. This study comprehensively analyzes the characteristics of sludge solid phase and elucidates the mechanism of sludge solid phase in the anaerobic degradation of toxic wastewater. The results show that the surface free energy of sludge solid phase after different pre-treatments is mainly contributed by Lewis acid-base hydration free energy. The distribution of proteins on the surface of sludge solid phase plays a major role in the adhesion between sludge solid particles. Metal ions in the sludge solid phase are mainly present in the exchange state, followed by the carbonate state and the organics-bound state. The sludge solid phase obtained by sludge pH 12 + 150 °C treatment has the highest conductivity (1.36 mS/m) and capacitance (25.51 μF/g), mainly due to the presence of melanoidins in the sludge solid phase, which has similar semiquinone radicals to humic acids, thus increasing conductivity. The addition of sludge solid phase promotes an increase in cumulative methane production and rate of methane production. The sludge solid phase might play a role of an auxiliary carbon source acting as an adsorbent to buffer against toxicity inhibition and facilitate electron transfer. This study reveals the characteristics of sludge solid phase and its role in anaerobic digestion, providing theoretical guidance for finding suitable resource utilization pathways for sludge solid phase.
Topics: Sewage; Anaerobiosis; Waste Disposal, Fluid; Wastewater; Biodegradation, Environmental; Water Pollutants, Chemical
PubMed: 38848921
DOI: 10.1016/j.scitotenv.2024.173769 -
Journal of Environmental Sciences... Nov 2024Anaerobic digestion has been defined as a competitive approach to facilitate the recycling of corn stalks. However, few studies have focused on the role of direct...
Anaerobic digestion has been defined as a competitive approach to facilitate the recycling of corn stalks. However, few studies have focused on the role of direct interspecies electron transfer (DIET) pathway in the acidification stage under the addition of different particle sizes of zero-valent iron (ZVI). In this study, three types of ZVI, namely iron filings, iron powder and nanoscale iron, were investigated, respectively, to enhance its high-value conversion. Variations in volatile fatty acids (VFAs) and methane (CH) production associated with the underlying mechanisms were emphatically determined. Results indicated that the addition of ZVI could increase the concentration of VFAs, with the most outstanding performance observed with the use of nanoscale iron. Importantly, the conversion of propionic acid to acetic acid was driven by adding ZVI with no between-group differences in acidizing phase. Conversely, the substrate was more fully utilized when supplied with iron powder compared with other groups in methanogenic phase, thereby displaying the maximum CH yield with a value of 263.1 mL/(g total solids (TS)). However, adding nanoscale iron could signally shorten the digestion time (T), saving 7 days in comparison to the group of iron powder.
Topics: Zea mays; Iron; Anaerobiosis; Methane; Fatty Acids, Volatile; Bioreactors
PubMed: 38844324
DOI: 10.1016/j.jes.2023.07.040 -
The Science of the Total Environment Sep 2024Due to the wide application in industries, copper can be detected in some nitrogen-rich wastewater. In this research, short-term and long-term experiments were conducted...
Due to the wide application in industries, copper can be detected in some nitrogen-rich wastewater. In this research, short-term and long-term experiments were conducted to explore the effects of Cu(II) on the anammox-denitrification couple system. It concluded that the half inhibition concentration (IC) of Cu(II) was 35.54 mg/L. The system in reactor could tolerate low concentrations of Cu(II) (≤5 mg/L), while the total nitrogen removal efficiency decreased from 93 % to 33 % under 10 mg/L of Cu(II). After 45 days exposure to Cu(II) (1-10 mg/L), 14.54 mg/g SS copper accumulated in the sludge, which largely inhibited the microbial activity. More extracellular polymeric substances (EPS) were secreted to defend against copper toxicity. Proteobacteria (19.18 %-44.04 %) was the dominant phylum and showed excellent tolerance and adaptability to Cu(II). The dominant anammox bacteria, Candidatus_Brocadia, was slightly enhanced under low concentrations of Cu(II), but was highly inhibited under 10 mg/L of Cu(II). PICRUSt2 results showed that some metabolic activities were suppressed under the exposure of copper while defensive responses were also induced. Metabolic disorders eventually led to the death of some microbes, resulting in unrecoverable deterioration in microbial activity. Overall, this study explores the effect of Cu(II) on the anammox-denitrification process and provides a possible inhibition mechanism.
Topics: Copper; Nitrogen; Waste Disposal, Fluid; Bioreactors; Denitrification; Water Pollutants, Chemical; Wastewater; Bacteria; Anaerobiosis
PubMed: 38839011
DOI: 10.1016/j.scitotenv.2024.173723 -
Cell Host & Microbe Jun 2024Antibiotic treatment promotes the outgrowth of intestinal Candida albicans, but the mechanisms driving this fungal bloom remain incompletely understood. We identify...
Antibiotic treatment promotes the outgrowth of intestinal Candida albicans, but the mechanisms driving this fungal bloom remain incompletely understood. We identify oxygen as a resource required for post-antibiotic C. albicans expansion. C. albicans depleted simple sugars in the ceca of gnotobiotic mice but required oxygen to grow on these resources in vitro, pointing to anaerobiosis as a potential factor limiting growth in the gut. Clostridia species limit oxygen availability in the large intestine by producing butyrate, which activates peroxisome proliferator-activated receptor gamma (PPAR-γ) signaling to maintain epithelial hypoxia. Streptomycin treatment depleted Clostridia-derived butyrate to increase epithelial oxygenation, but the PPAR-γ agonist 5-aminosalicylic acid (5-ASA) functionally replaced Clostridia species to restore epithelial hypoxia and colonization resistance against C. albicans. Additionally, probiotic Escherichia coli required oxygen respiration to prevent a post-antibiotic bloom of C. albicans, further supporting the role of oxygen in colonization resistance. We conclude that limited access to oxygen maintains colonization resistance against C. albicans.
PubMed: 38838675
DOI: 10.1016/j.chom.2024.05.008 -
Water Research Aug 2024Dissolved organic matter (DOM) plays an important role in regulating the fate of mercury (Hg), e.g., mobility, bioavailability, and toxicity. Clarifying the role of DOM...
Dissolved organic matter (DOM) plays an important role in regulating the fate of mercury (Hg), e.g., mobility, bioavailability, and toxicity. Clarifying the role of DOM in binding Hg in the treatment processes of sewage sludge is important for relieving Hg contamination risks in land applications. However, the impacts of DOM on Hg binding in sewage sludge are still unclear. In this study, we investigated the evolution of Hg and its speciation in full-scale sludge anaerobic digestion (AD) with thermal hydrolysis. The role of DOM in binding Hg(II) was further analyzed. The results showed that AD with thermal hydrolysis led to an increase in the Hg content in the sludge (from 3.72 ± 0.47 mg/kg to 10.75 ± 0.16 mg/kg) but a decrease in Hg mobility (the mercury sulfide fraction increased from 60.56 % to 79.78 %). Further adsorption experiments revealed that at equivalent DOM concentrations, DOM with a low molecular weight (MW<1 kDa) in activated sludge, DOM with a medium molecular weight (1 kDa
5 kDa) in both anaerobically digested sludge and conditioned sludge showed high binding amounts of Hg(II), with 1372.54, 535.28, 942.09 and 801.51 mg Hg/g DOM, respectively. Parallel factor analysis (PARAFAC) and fluorescence quotient (FQ) results showed that tryptophan-like and tyrosine-like substances had high binding affinities for Hg(II). Furthermore, X-ray photoelectron spectroscopy (XPS) indicated that the reduced organic sulfur contained in the DOM was potentially bound to Hg through the interactions of Hg-S and Hg-O. These results indicated that DOM may play special roles in regulating Hg speciation. The association between DOM and Hg(II), such as the significant positive correlation (p < 0.05) between the dissolution rate of Hg(II) and release of tryptophan-like substances during thermal hydrolysis, suggested the potential way for removing Hg from sludge. Topics: Mercury; Sewage; Anaerobiosis; Hydrolysis; Adsorption; Water Pollutants, Chemical; Organic Chemicals; Waste Disposal, Fluid
PubMed: 38838483
DOI: 10.1016/j.watres.2024.121845