To use the selective inhibition method for quantitative analysis of acetate metabolism in methanogenic systems,the responses of microbial communities and metabolic activities,which were involved in anaerobic degradati...To use the selective inhibition method for quantitative analysis of acetate metabolism in methanogenic systems,the responses of microbial communities and metabolic activities,which were involved in anaerobic degradation of acetate,to the addition of methyl fluoride（CH3F）,2-bromoethanesulfonate（BES）and hydrogen were investigated in a thermophilic batch experiment.Both the methanogenic inhibitors,i.e.,CH3F and BES,showed their effectiveness on inhibiting CH4 production,whereas acetate metabolism other than acetoclastic methanogenesis was stimulated by BES,as reflected by the fluctuated acetate concentration.Syntrophic acetate oxidation was thermodynamically blocked by hydrogen（H2）,while H2-utilizing reactions as hydrogenotrophic methanogenesis and homoacetogenesis were correspondingly promoted.Results of PCR-DGGE fingerprinting showed that,CH3F did not influence the microbial populations significantly.However,the BES and hydrogen notably altered the bacterial community structures and increased the diversity.BES gradually changed the methanogenic community structure by affecting the existence of different populations to different levels,whilst H2 greatly changed the abundance of different methanogenic populations,and induced growth of new species.展开更多
Conductive materials(CM)can improve methane production(MP)efficiency in many methanogenic systems.However,several types of CM exist,and there are uncertainties regarding whether they all improve MP efficiency to the s...Conductive materials(CM)can improve methane production(MP)efficiency in many methanogenic systems.However,several types of CM exist,and there are uncertainties regarding whether they all improve MP efficiency to the same extent and modulate microbial communities in a similar way.To investigate that,different microbial enrichments with and without activated carbon(AC),magnetite(Mag),and zeolites(Zeo)(at 0.5 g/L)were developed.MP profiles and microbial composition changes were compared among enrichments.The behavior of all enrichments was different,although the initial inoculum sludge was the same.Lag phase duration was lower in AC enrichment,while the complete conversion of butyrate to methane was faster in Mag enrichment.Syntrophomonas was the most abundant bacterial genus in all enrichments,but changes in the methanogenic community were evident.Acetoclastic methanogens were more diverse in Mag enrichment,with microorganisms assigned to Methanosarcina and Methanothrix gener1,but Methanothrix was the only acetoclastic methanogen in the other enrichments.On the other hand,different species of hydrogenotrophic methanogens prevailed in distinct enrichments.The metatranscriptomics results revealed that the dominant mechanism of interspecies electron transfer in the AC enrichment utilized hydrogen as the electron carrier,and no evidences of direct interspecies electron transfer(DIET)could be found.These results showed how different CM modulate microbial communities and affect MP efficiency through mechanisms that do not necessarily involve DIET or mediation via CM.展开更多
Background Sustainable livestock production is essential for food security and environmental management.Lignocellulosic biomass can be used in animal feed,thereby reducing feed production costs and enhancing sustainab...Background Sustainable livestock production is essential for food security and environmental management.Lignocellulosic biomass can be used in animal feed,thereby reducing feed production costs and enhancing sustainability.Expansin-like proteins(ELPs)play essential roles in plant cell wall degradation,yet their functions remain largely underexplored in rumen microbes.The purpose of this study was to investigate the effects of rumen microbial ELPs on lignocellulose degradation.Results This study systematically identified 396 ELPs within the rumen microbiota,uncovering remarkable diversity,particularly among anaerobic fungi.Three representative ELPs from Pecoramyces ruminantium F1(PFLoos_1,PFSWO1_1,PFSWO2_1)were selected for biochemical characterization.While PFSWO2_1 could not be expressed,PFLoos_1 and PFSWO1_1 exhibited significant synergy with cellulases.The CBM10-containing PFSWO1_1 demonstrated superior thermal stability(up to 65°C)and substrate affinity,increasing rice straw hydrolysis efficiency by 21.6%(reducing sugar yield)compared to cellulase alone.Structural analyses revealed that CBM10 enabled PFSWO1_1 to preferentially bind complex substrates,whereas the single-domain PFLoos_1 targeted simpler substrates.Notably,ELP pretreatment of corn stover significantly improved fermentation quality(pH and lactic acid)and nutritional value(neutral detergent fiber,acid detergent fiber,and water-soluble carbohydrates).Conclusions These findings indicate that ELPs are abundant in the rumen and play a synergistic role in lignocellulosic biomass conversion.展开更多
In this study,the effects of different salinity gradients and addition of compatible solutes on anaerobic treated effluent water qualities,sludge characteristics and microbial communities were investigated.The increas...In this study,the effects of different salinity gradients and addition of compatible solutes on anaerobic treated effluent water qualities,sludge characteristics and microbial communities were investigated.The increase in salinity resulted in a decrease in particle size of the granular sludge,which was concentrated in the range of 0.5-1.0 mm.The content of EPS(extracellular polymeric substances)in the granular sludge gradually increased with increasing salinity and the addition of betaine(a typical compatible solute).Meanwhile,the microbial community structure was significantly affected by salinity,with high salinity reducing the diversity of bacteria.At higher salinity,Patescibacteria and Proteobacteria gradually became the dominant phylum,with relative abundance increasing to 13.53%and 12.16%at 20 g/L salinity.Desulfobacterota and its subordinate Desulfovibrio,which secrete EPS in large quantities,dominated significantly after betaine addition.Their relative abundance reached 13.65%and 7.86%at phylum level and genus level.The effect of these changes on the treated effluent was shown as the average chemical oxygen demand(COD)removal rate decreased from 82.10%to 79.71%,78.01%,68.51%and 64.55%when the salinity gradually increased from 2 g/L to 6,10,16 and 20 g/L.At the salinity of 20 g/L,average COD removal increased to 71.65%by the addition of 2 mmol/L betaine.The gradient elevated salinity and the exogenous addition of betaine played an important role in achieving stability of the anaerobic system in a highly saline environment,which provided a feasible strategy for anaerobic treatment of organic saline wastewater.展开更多
Anaerobic oxidation of methane(AOM)can contribute to reducing methane emissions in landfills;however,the AOM rates vary depending on the inoculum source.This study addressed the capacity of AOM of a fermentative micro...Anaerobic oxidation of methane(AOM)can contribute to reducing methane emissions in landfills;however,the AOM rates vary depending on the inoculum source.This study addressed the capacity of AOM of a fermentative microbial community derived from a reactor treatingmunicipal solidwastes.First,the inoculum’s autotrophic capacitywas verified using a gasmixture of 75% CO_(2) and 25% H_(2).Results demonstrated that the fermentative microbial community reached amaximum CO_(2) consumption rate of 22.5±1.2 g CO_(2)/(m^(3)·h),obtaining acetate as the main product.Then,the inoculum was grown on a gas mixture of 50%CH_(4),35%CO_(2),and 15%N_(2),using iron(Fe^(3+))as the electron acceptor.The AOM rates increased over time and peaked at 3.1±0.9 g CH_(4)/(m^(3)·h)by 456 h with the simultaneous consumption of CO_(2).Acetate was the main product,with amaximum concentration of 180±9mg/L.By 408 h,a bacterial cluster of indicator species correlated with the AOM rates,including to Rhodobactereceae(r=0.80),Oceanicola(r=0.80),Propionicicella(r=0.77),Christensenellaceae(r=0.58),Oscillospiraceae(r=0.53),Mobilitalea(r=0.66),Hungateiclostridiaceae(r=0.46),and Izemoplasmatales(r=0.77).Methanosarcina,Methanobacterium,and Methanoculleus correlated with the AOM and CO_(2) consumption rates.A co-occurrence network analysis showed that Methanosarcina positively interacted with syntrophic bacteria like Christensenellaceae and Acinetobacter and diverse heterotrophic bacteria.This study demonstrated the feasibility of obtaining a CH_(4)-oxidizing microbial community in 16 days,exhibiting AOM rates higher than those reported for soils.展开更多
Acupuncture is used worldwide to treat migraine,but its scientific mechanism remains unclear.Here,we report a 1H NMR metabolomics study involving 40 migraine patients and 10 healthy individuals randomly receiving acup...Acupuncture is used worldwide to treat migraine,but its scientific mechanism remains unclear.Here,we report a 1H NMR metabolomics study involving 40 migraine patients and 10 healthy individuals randomly receiving acupuncture or sham acupuncture,followed by machine learning techniques and functional analysis.We found that acupuncture at acupoints particularly enhanced anaerobic glycolysis and modified mitochondrial function by adjusting the levels of plasma pyruvic acid(p=0.012),lactic acid(p=0.031)and citrate(p=0.00079)at a Bonferroni-corrected level of significance compared to the pre-treatment level of these three metabolites in migraine patients.Therefore,acupuncture supplies energy to migraine patients and relieves migraine attacks.In contrast,we observed that sham acupuncture may partially supply energy to migraine patients through lipid metabolism by changing the levels of plasma lipid(p=0.0012),glycerine(p=0.021),and pyruvic acid(p=0.047)at a Bonferroni-corrected level of significance.The functional network analysis further indicates this different way of supplying energy contributes to the different effects of acupuncture and sham acupuncture.Our find-ings reveal novel metabolic evidence for the specific effect of acupuncture in relation to sham acupuncture.This metabolic evidence could enlighten a brand new direction into acupuncture analgesia mechanism,which in turn would pose fresh challenges for future acupuncture research.展开更多
Manure slurry application to farmland reduces chemical fertilizer use,mitigates pollution,and improves soil fertility.However,researches on the role of anaerobically treated cow slurry applied to soil microorganisms i...Manure slurry application to farmland reduces chemical fertilizer use,mitigates pollution,and improves soil fertility.However,researches on the role of anaerobically treated cow slurry applied to soil microorganisms in Northeast China remain underexplored.Here,in laboratory incubation experiments,different treatments including various combinations of sterilized and non-sterilized soil and slurry,and different application rates were employed to examine the effects of indigenous microorganisms on soil microbial communities.Field-collected soil samples were employed to examine the responses and spatial variations of soil microbes under production conditions.The results indicated that indigenous soil microorganisms exerted a dominant influence in the microbial community variations,while the impact of cow slurry microbiota on community diversity was relatively minor.At the phylum level,Proteobacteria(P=0.031,R=0.969)showed a significant positive correlation with the slurry application,whereas Acidobacteriota(P=0.012,R=–0.988)and Basidiomycota(P=0.01,R=–0.99)showed significant negative correlations.In the field environment,the autumn slurry application effects on soil microbes in the following year were not significant.In contrast,under spring slurry application,the cow slurry-soil agglomerations led to significant spatial differences in soil microbial communities,with higher microbial diversity observed in the vicinity of agglomerations.The microbes in agglomerations,such as Actinomycetes,Bacteroides and Proteobacteria,were found to be beneficial for the crop residue decomposition.These microorganisms could decompose organic compounds including lignin,cellulose,hemicellulose,and xylan in crop straw.Overall,slurry application indeed influenced soil microbes and induced spatial variations,providing insights for sustainable agricultural practices.展开更多
Background Coumarins are toxic phytochemicals found in a variety of plants and are known to limit microbial degradation and interfere with nutrient cycling.While the degradation of coumarins by fungi has been studied ...Background Coumarins are toxic phytochemicals found in a variety of plants and are known to limit microbial degradation and interfere with nutrient cycling.While the degradation of coumarins by fungi has been studied in an environmental context,little is known about their degradation in the gastrointestinal system of herbivores after ingestion.Results In this study,we investigated in vitro fermentation by microbial enrichment,transcriptome sequencing,and high-resolution mass spectrometry to evaluate the ability of rumen anaerobic fungi to degrade coumarins.The results showed that despite the low abundance of anaerobic fungi in the rumen microbiota,they were able to effectively degrade coumarins.Specifically,Pecoramyces ruminantium F1 could tolerate coumarin concentrations up to 3 mmol/L and degrade it efficiently via metabolic pathways involving alpha/beta hydrolases and NAD(P)H oxidoreductases within the late growth phase.The fungus metabolized coumarin to less toxic compounds,including o-coumaric acid and melilotic acid,highlighting the detoxification potential of anaerobic fungi.Conclusions This study is the first to demonstrate the ability of rumen anaerobic fungi to degrade coumarin,providing new insights into the use of anaerobic fungi in sustainable agricultural practices and environmental detoxification strategies.展开更多
Peri-implantitis is a bacterial infection that causes soft tissue inflammatory lesions and alveolar bone resorption,ultimately resulting in implant failure.Dental implants for clinical use barely have antibacterial pr...Peri-implantitis is a bacterial infection that causes soft tissue inflammatory lesions and alveolar bone resorption,ultimately resulting in implant failure.Dental implants for clinical use barely have antibacterial properties,and bacterial colonization and biofilm formation on the dental implants are major causes of peri-implantitis.Treatment strategies such as mechanical debridement and antibiotic therapy have been used to remove dental plaque.However,it is particularly important to prevent the occurrence of peri-implantitis rather than treatment.Therefore,the current research spot has focused on improving the antibacterial properties of dental implants,such as the construction of specific micro-nano surface texture,the introduction of diverse functional coatings,or the application of materials with intrinsic antibacterial properties.The aforementioned antibacterial surfaces can be incorporated with bioactive molecules,metallic nanoparticles,or other functional components to further enhance the osteogenic properties and accelerate the healing process.In this review,we summarize the recent developments in biomaterial science and the modification strategies applied to dental implants to inhibit biofilm formation and facilitate bone-implant integration.Furthermore,we summarized the obstacles existing in the process of laboratory research to reach the clinic products,and propose corresponding directions for future developments and research perspectives,so that to provide insights into the rational design and construction of dental implants with the aim to balance antibacterial efficacy,biological safety,and osteogenic property.展开更多
Anaerobic digestion(AD)is widely employed for sludge stabilization and waste reduction.However,the slow hydrolysis process hinders methane production and leads to prolonged sludge issues.In this study,an efficient and...Anaerobic digestion(AD)is widely employed for sludge stabilization and waste reduction.However,the slow hydrolysis process hinders methane production and leads to prolonged sludge issues.In this study,an efficient and eco-friendly lysozyme pre-treatment method was utilized to address these challenges.By optimizing lysozyme dosage,hydrolysis and cell lysis were maximized.Furthermore,lysozyme combined with hydrothermal pretreatment enhanced overall efficiency.Results indicate that:(1)When lysozyme dosage reached 90 mg/g TS after 240 min of pretreatment,SCOD,soluble polysaccharides,and protein content reached their maxima at 855.00,44.09,and 204.86 mg/L,respectively.This represented an increase of 85.87%,365.58%,and 259.21%compared to the untreated sludge.Threedimensional fluorescence spectroscopy revealed the highest fluorescence intensity in the IV region(soluble microbial product),promoting microbial metabolic activity.(2)Lysozyme combined with hydrothermal pretreatment significantly increased SCOD,soluble proteins,and polysaccharide release from sludge,reducing SCOD release time.Orthogonal experiments identified Group 3 as the most effective for SCOD and soluble polysaccharide release,while Group 9 released the most soluble proteins.The significance order of factors influencing SCOD,soluble proteins,and polysaccharide release is hydrothermal temperature>hydrothermal time>enzymatic digestion time.(3)The lysozyme-assisted hydrothermal pretreatment group exhibited the fastest release and the highest SCOD concentration of 8,135.00 mg/L during anaerobic digestion.Maximum SCOD consumption and cumulative gas production increased by 95.89%and 130.58%,respectively,compared to the control group,allowing gas production to conclude 3 days earlier.展开更多
Probiotics have been demonstrated to be effective and safe for hyperuricemia(HUA)and gout treatment.Hence,identifying microbes with high uric acid-or purine-metabolizing ability is highly important.Due to the high loa...Probiotics have been demonstrated to be effective and safe for hyperuricemia(HUA)and gout treatment.Hence,identifying microbes with high uric acid-or purine-metabolizing ability is highly important.Due to the high load of uric acid in chicken feces,we hypothesized that the chicken gut would be an excellent source for new uric acid or purine-metabolizing microbes.In this study,we examined chicken gut contents to isolate an Enterococcus faecalis strain(designated CML390)that displayed high uric acid-degrading ability.In vitro experiments indicated that E.faecalis CML390 could effectively metabolize uric acid under both aerobic and anaerobic conditions,and the richer the nutrients,the higher the rate of uric acid degradation.By integrating genomics,transcriptomics,and metabolomics analyses,we revealed two pathways involved in aerobic and anaerobic uric acid degradation,respectively,in this isolate.E.faecalis CML390 relies on oxygen to metabolize uric acid into substances such as allantoin under aerobic conditions,while it also harbors a conserved uric acid-inducible gene cluster for anaerobic uric acid metabolism.An in vivo experiment showed that gavage with live E.faecalis CML390 in a mouse model of HUA(established using a combination of uric acid and potassium oxonate)significantly reduced serum uric acid levels and alleviated HUA.Our findings contribute to the exploration of the pathways and mechanisms of uric acid metabolism in intestinal microorganisms and provide a candidate probiotic for the treatment of HUA and gout.展开更多
Global warming and human activities have reduced the concentrations of dissolved oxygen in the bottom water of lakes,resulting in increased anoxia in surface sediments.This increased anoxia likely alters carbon cyclin...Global warming and human activities have reduced the concentrations of dissolved oxygen in the bottom water of lakes,resulting in increased anoxia in surface sediments.This increased anoxia likely alters carbon cycling processes(e.g.,organic carbon mineralization)by altering microbial community composition and functions in lakes.However,it remains unclear how organic carbon mineralization responds to increased anoxia in surface sediments of lakes(particularly saline lakes).In this study,CO_(2)production in surface sediments of six lakes with different salinity(0.47-250 g/L)on the Tibetan Plateau was investigated using microcosm incubations under aerobic and anaerobic conditions,respectively,followed by geochemical and microbial analyses.The results showed that for the freshwater lake,CO_(2)production rates in anaerobic sediment microcosms were significantly(P<0.05)lower than their aerobic counterparts.In contrast,an opposite trend was observed for CO_(2)production in saline lakes.Furthermore,the CO_(2)production rates decreased significantly(P<0.05)under aerobic conditions,while it exhibited a hump-like relationship with increasing salinity under anaerobic conditions.Taken together,our results suggest that increased anoxia would enhance organic carbon mineralization in surface sediments of saline lakes and help understand carbon feedback on global changes in saline lakes.展开更多
The Anaerobic Digestion Model No.1(ADM1)has been modified to include enhanced kinetic parameters,which more precisely simulate methane production during the anaerobic digestion of diverse organic solid wastes.Calibrat...The Anaerobic Digestion Model No.1(ADM1)has been modified to include enhanced kinetic parameters,which more precisely simulate methane production during the anaerobic digestion of diverse organic solid wastes.Calibration and validation of the model were achieved using experimental data from batch fermentation processes.Simulations of the updated ADM1 were conducted using AQUASIM 2.0 software.Sensitivity analysis helped identify and assess the most critical kinetic parameters affecting biogas production.Key parameters such as the microorganism decay constant(d^(-1)),disintegration rate constant(d^(-1)),Monod maximum specific substrate uptake rate(gCOD/gVSS·d),and half⁃saturation constants were found to significantly influence biogas yield.The optimal values for these parameters were identified as 0.03,6.07,3.64,and 0.27,respectively.These optimized values were validated through batch experiments.The modified ADM1 successfully predicted methane production,achieving R2 values greater than 0.8 in all validation trials.Key methanogens,Methanosarcina and Methanosaeta,were identified,and their enrichment during mixed fermentation of various organic solid wastes indicated enhanced methane production via aceticlastic methanogenesis.The microbial characterization and simulations using the modified ADM1 model supported each other.展开更多
Red anaerobic ammonia oxidation (Anammox) granular sludge (AnGS) has been reported insuccessfully operating Anammox systems, and its color is associated with sludge activity.However, in long-term operating systems, An...Red anaerobic ammonia oxidation (Anammox) granular sludge (AnGS) has been reported insuccessfully operating Anammox systems, and its color is associated with sludge activity.However, in long-term operating systems, AnGS exhibits different sensory colors, physicalstructures, community structures, and denitrification performance, but the relationship betweenthem has not yet been elucidated.The AnGS of the Anammox system, which has beenin operation for more than a decade, can be divided into twomain categories: red and white.The specific Anammox activity (SAA) in conventional red AnGS increased continuously asthe particle size increased from <0.51 mm to 6.02 ± 0.84 mm. The SAA of white AnGS wereslightly lower than those of red AnGS with similarly-size granules but significantly higherthan AnGS with smaller red granules. Compared with red AnGS, the extracellular polymericsubstances of white AnGS were significantly reduced,mainly due to the higher intracellulariron content, resulting in lower heme c concentration. Thus, heme c may prove not to bean evaluative tool for measuring Anammox activity. Red and white AnGS, whether throughself-aggregation or adsorption by hydroxyl apatite and other carriers, will face the fate ofinternal voids during particle size growth. White AnGS exhibited amore complex microbialcommunity than red AnGS. Candidatus Brocadia was abundant in red AnGS and the abundanceincreased with increasing granule size. Candidatus Kuenenia and Candidatus Jetteniamade significant contributions to denitrification in white AnGS. This study provides a newperspective on particle selection for anammox engineering applications.展开更多
Consecutive stresses,such as initial submergence during germination followed by water deficit during the seedling stage,pose significant challenges to direct-seeded rice cultivation.By Linkage disequilibrium analysis,...Consecutive stresses,such as initial submergence during germination followed by water deficit during the seedling stage,pose significant challenges to direct-seeded rice cultivation.By Linkage disequilibrium analysis,Sub1 and Dro1(Δbp:10 Mb),as well as Sub1 and TPP7(Δbp:6 Mb)were identified to exhibit long-range linkage disequilibrium(LRLD).Meta-QTL analysis further revealed that Sub1 and TPP7 co-segregated for tolerance to submergence at the germination and seedling stages.Based on this,we hypothesized that LRLD might influence plant responses to consecutive stresses.To test this hypothesis,we developed a structured recombinant inbred line population from a cross between Bhalum 2 and Nagina 22,with alleles(Sub1 and TPP7)in linkage equilibrium.Mendelian randomization analysis validated that the parental alleles,rather than the recombinant alleles of Sub1 and TPP7,significantly influenced 13 out of 41 traits under consecutive stress conditions.Additionally,16 minor additive effect QTLs were detected between the genomic regions,spanning Sub1 and TPP7 for various traits.A single allele difference between these genomic regions enhanced crown root number,root dry weight,and specific root area by 11.45%,15.69%,and 33.15%,respectively,under flooded germination conditions.Candidate gene analysis identified WAK79 and MRLK59 as regulators of stress responses during flooded germination,recovery,and subsequent water deficit conditions.These findings highlight the critical role of parental allele combinations and genomic regions between Sub1 and TPP7 in regulating the stress responses under consecutive stresses.Favourable haplotypes derived from these alleles can be utilized to improve stress resilience in direct-seeded rice.展开更多
Sewage sludge in cities of Yangzi River Belt,China,generally exhibits a lower organic content and higher silt contentdue to leakage of drainage system,which caused low bioenergy recovery and carbon emission benefits i...Sewage sludge in cities of Yangzi River Belt,China,generally exhibits a lower organic content and higher silt contentdue to leakage of drainage system,which caused low bioenergy recovery and carbon emission benefits in conventional anaerobic digestion(CAD).Therefore,this paper is on a pilot scale,a bio-thermophilic pretreatment anaerobic digestion(BTPAD)for low organic sludge(volatile solids(VS)of 4%)was operated with a long-term continuous flow of 200 days.The VS degradation rate and CH_(4) yield of BTPAD increased by 19.93%and 53.33%,respectively,compared to those of CAD.The analysis of organic compositions in sludge revealed that BTPAD mainly improved the hydrolysis of proteins in sludge.Further analysis of microbial community proportions by high-throughput sequencing revealed that the short-term bio-thermophilic pretreatment was enriched in Clostridiales,Coprothermobacter and Gelria,was capable of hydrolyzing acidified proteins,and provided more volatile fatty acid(VFA)for the subsequent reaction.Biome combined with fluorescence quantitative polymerase chain reaction(PCR)analysis showed that the number of bacteria with high methanogenic capacity in BTPAD was much higher than that in CAD during the medium temperature digestion stage,indicating that short-term bio-thermophilic pretreatment could provide better methanogenic conditions for BTPAD.Furthermore,the greenhouse gas emission footprint analysis showed that short-term bio-thermophilic pretreatment could reduce the carbon emission of sludge anaerobic digestion system by 19.18%.展开更多
Microbial consortia that catalyze chain elongation processes have been enriched using different selection strategies,for which the electron donor is an essential one.Propanol is an extraordinarily promising electron d...Microbial consortia that catalyze chain elongation processes have been enriched using different selection strategies,for which the electron donor is an essential one.Propanol is an extraordinarily promising electron donor because it can be generated from renewable resources,including lignocellulosic biomass and protein wastes.Here,propanol was proven in detail to be an efficient electron donor,enhancing the production of odd medium-chain carboxylates during chain elongation.By exploring various electron acceptors,reactor conditions,and electron donor/electron acceptor mol ratios,our study highlights that acetate is the most suitable electron acceptor for the production of both odd-and even-chain carboxylates.The optimal conditions for propanol-based chain elongation were 30℃ and pH 6,achieving 82.8%selectivity for odd-chain carboxylates.Another critical insight from our work is that a propanol/acetate mol ratio of 1:1 can minimize the inhibitory effect of propanol and maximize the yield of medium-chain carboxylates,with the highest concentration of n-heptanoate reaching 124.5 mmol C/L.This was further illustrated by 16S rRNA amplicon sequencing,which elucidated that the community composition and keystone species in a propanol-based reactor closely resembled that of the ethanol one.The dominant phylum of the propanol-based reactor,Firmicutes showed a significant positive correlation with the concentrations of n-caproate and n-valerate.Additionally,the co-occurrence of Clostridium sensu stricto 12 and Oscillibacter,known as typical chain elongators,was identified within the propanol-based reactor.These findings enhance our understanding of propanolbased chain elongation,offer guiding principles for reactor microbiota assembly,and support efficient odd medium-chain carboxylate production.展开更多
Anaerobic fermentation is an efficient method to extract phosphorus from excess sludge,thereby facilitating its recovery and mitigating the phosphorus resource shortage.However,the prevalent metal-bound phosphorus spe...Anaerobic fermentation is an efficient method to extract phosphorus from excess sludge,thereby facilitating its recovery and mitigating the phosphorus resource shortage.However,the prevalent metal-bound phosphorus species within sludge was difficult to release into the fermentation liquor.To address this,this study evaluated the enhanced phosphorus release performance from sludge containing iron-phosphorus compounds(Fe-P)via co-fermenting it with agriculture wastes.Specifically,protein-rich feather(Feather Group)and polysaccharide-rich tea residue(Tea Group)was respectively dosed into batch-scale fermentation jar.Results showed that the Feather Group exhibited significantly higher levels of released soluble phosphorus(2.1 folds)and volatile fatty acids(41.4 folds)compared to the Control Group,with concentrations reaching up to 280 mg/L and 9366 mg chemical oxygen demand/L,respectively.The activities ofα-glucosidase,neutral protease and acetate kinase in the Feather group were increased by 11.1%,92.3%and 37.6%,respectively,compared with the Control group.Methanogen abundance decreased while hydrolytic acid-producing bacteria and iron-reducing bacteria increased significantly after supplying agricultural wastes.Metagenomic analysis demonstrated a significant increase in genes related to acetic acid synthesis.Mechanism elucidation suggested that increased iron-reducing bacteria abundance promoted Fe3+reduction into Fe2+,thus enhancing phosphorus release from Fe-P compounds.This work may provide valuable information for developing effective strategy to extract phosphorus resource from complex environmental wastes.展开更多
Cresyl diphenyl phosphate(CDP),an emerging aryl organophosphate ester(OPE),exhibits potential toxic effects and is frequently found in diverse environmental media,thereby raising concerns about environmental pollution...Cresyl diphenyl phosphate(CDP),an emerging aryl organophosphate ester(OPE),exhibits potential toxic effects and is frequently found in diverse environmental media,thereby raising concerns about environmental pollution.Biodegradation demonstrates substantial potential for CDP removal from the environment.This study investigated the biodegradation mechanisms of CDP using anaerobic activated sludge(AnAS).The biodegradation of 1-mg/L CDP followed a first-order kinetic model with a degradation kinetic constant of 0.943 d^(-1),and the addition of different electron acceptors affected the degradation rate.High-resolution mass spectrometry identified seven transformation products(TPs)of CDP.The pathways of CDP degradation in anaerobic conditions were proposed,with carboxylation products being the most dominant intermediate products.The structure of the anaerobic microbial community at different degradation time points in CDP-amended microcosms was examined.The linear discriminant analysis(LDA)of effect size(LEfSe)potentially underscored the pivotal role of Methyloversatilis in CDP biodegradation.Zebrafish embryotoxicity experiments revealed both lethal and morphogenetic impacts of CDP on zebrafish embryos.The survival rate,hatching rate,and body length indicators of zebrafish embryos underscored the detoxification of CDP and its resultant intermediates by AnAS.This study offers new insights into the fate and biodegradation mechanisms of CDP in wastewater treatment plants.展开更多
The organic matter inmunicipal wastewater can be recovered by anaerobic biological treatment,making further resource utilization of municipal wastewater,which meets the requirements of sustainable development.An upflo...The organic matter inmunicipal wastewater can be recovered by anaerobic biological treatment,making further resource utilization of municipal wastewater,which meets the requirements of sustainable development.An upflow anaerobic biofilter(UAF)treating municipal wastewater was established.The performances of stable operation and recovery operation of UAF after long-term starvation(234 days)and the changes of microbial community structure were researched.By gradually reducing HRT from 10 h to 4 h,the UAF achieved the treatment performance of pre-starvation after only 50 days recovery operation,in which total COD and soluble COD removal efficiencies reached 66%and 69%,respectively,and the CH_(4) production rate was 0.21 L CH_(4)/g CODremoval.The recovery performance of UAF after long term starvation showed that the recovery sequence of three main anaerobic processes was hydrolytic acidification,hydrogen-acetate production and methanogenesis.High-throughput sequencing results indicated that dominant bacteria associated with hydrolytic acidification process changed from Moduliflexaceae and Trichococcus in stable operation stage to Trichococcus and Romboutsia in recovery stage.Besides,the dominant archaea changed from Methanosaeta(hydrotrophic methanogens)to Methanobacterium(acetotrophic methanogens),showing Methanobacterium was more resistant to starvation environment.Therefore,by using UAF for biological treatment of organic matter,even after a long period of starvation,the system would not be completely destroyed.Once it resumed operation,the treatment performance could be restored in a short period of time.展开更多
基金supported by the National Basic Research Program (973) of China (No. 2012CB719801)the National Natural Science Foundation of China (No. 51178327+2 种基金21177096)the Innovation Program of Shanghai Municipal Education Commission (No. 13ZZ030)the Shanghai Pujiang Program (No. 11PJ1409200)
文摘To use the selective inhibition method for quantitative analysis of acetate metabolism in methanogenic systems,the responses of microbial communities and metabolic activities,which were involved in anaerobic degradation of acetate,to the addition of methyl fluoride（CH3F）,2-bromoethanesulfonate（BES）and hydrogen were investigated in a thermophilic batch experiment.Both the methanogenic inhibitors,i.e.,CH3F and BES,showed their effectiveness on inhibiting CH4 production,whereas acetate metabolism other than acetoclastic methanogenesis was stimulated by BES,as reflected by the fluctuated acetate concentration.Syntrophic acetate oxidation was thermodynamically blocked by hydrogen（H2）,while H2-utilizing reactions as hydrogenotrophic methanogenesis and homoacetogenesis were correspondingly promoted.Results of PCR-DGGE fingerprinting showed that,CH3F did not influence the microbial populations significantly.However,the BES and hydrogen notably altered the bacterial community structures and increased the diversity.BES gradually changed the methanogenic community structure by affecting the existence of different populations to different levels,whilst H2 greatly changed the abundance of different methanogenic populations,and induced growth of new species.
基金supported by the Portuguese Foundation for Science and Technology(FCT)under the scope of the strategic funding of UIDB/04469/2020 unit and by the CM4Methane project(Ref:PTDC/BTA-BTA/2249/2021,DOI 10.54499/PTDC/BTABTA/2249/2021)FCT and European Union(EU),through the Portuguese State Budget and the European Social Fund under the scope of Norte2020-Programa Operacional Regional do Norte,also funded the SFRH/BD/132003/2017 and COVID/BD/152431/2022 grants held by Cátia S.N.Braga.,and the SFRH/BD/147271/2019 grant held by João C.Sequeira.M.SaloméDuarte acknowledges FCT for the Junior Research contract obtained under the scope of the Scientific Stimulus Employment 2022(ref:2022.06569.CEECIND/CP1718/CT0004,doi:https://doi.org/10.54499/2022.06569.CEECIND/CP1718/CT0004)PhD M.Fernando R.Pereira and PhD O.SaloméG.Soares from the Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials,Faculty of Engineering(University of Porto),for providing the AC used in this study.
文摘Conductive materials(CM)can improve methane production(MP)efficiency in many methanogenic systems.However,several types of CM exist,and there are uncertainties regarding whether they all improve MP efficiency to the same extent and modulate microbial communities in a similar way.To investigate that,different microbial enrichments with and without activated carbon(AC),magnetite(Mag),and zeolites(Zeo)(at 0.5 g/L)were developed.MP profiles and microbial composition changes were compared among enrichments.The behavior of all enrichments was different,although the initial inoculum sludge was the same.Lag phase duration was lower in AC enrichment,while the complete conversion of butyrate to methane was faster in Mag enrichment.Syntrophomonas was the most abundant bacterial genus in all enrichments,but changes in the methanogenic community were evident.Acetoclastic methanogens were more diverse in Mag enrichment,with microorganisms assigned to Methanosarcina and Methanothrix gener1,but Methanothrix was the only acetoclastic methanogen in the other enrichments.On the other hand,different species of hydrogenotrophic methanogens prevailed in distinct enrichments.The metatranscriptomics results revealed that the dominant mechanism of interspecies electron transfer in the AC enrichment utilized hydrogen as the electron carrier,and no evidences of direct interspecies electron transfer(DIET)could be found.These results showed how different CM modulate microbial communities and affect MP efficiency through mechanisms that do not necessarily involve DIET or mediation via CM.
基金funded by the National Natural Science Foundation of China(grant nos.32372905)。
文摘Background Sustainable livestock production is essential for food security and environmental management.Lignocellulosic biomass can be used in animal feed,thereby reducing feed production costs and enhancing sustainability.Expansin-like proteins(ELPs)play essential roles in plant cell wall degradation,yet their functions remain largely underexplored in rumen microbes.The purpose of this study was to investigate the effects of rumen microbial ELPs on lignocellulose degradation.Results This study systematically identified 396 ELPs within the rumen microbiota,uncovering remarkable diversity,particularly among anaerobic fungi.Three representative ELPs from Pecoramyces ruminantium F1(PFLoos_1,PFSWO1_1,PFSWO2_1)were selected for biochemical characterization.While PFSWO2_1 could not be expressed,PFLoos_1 and PFSWO1_1 exhibited significant synergy with cellulases.The CBM10-containing PFSWO1_1 demonstrated superior thermal stability(up to 65°C)and substrate affinity,increasing rice straw hydrolysis efficiency by 21.6%(reducing sugar yield)compared to cellulase alone.Structural analyses revealed that CBM10 enabled PFSWO1_1 to preferentially bind complex substrates,whereas the single-domain PFLoos_1 targeted simpler substrates.Notably,ELP pretreatment of corn stover significantly improved fermentation quality(pH and lactic acid)and nutritional value(neutral detergent fiber,acid detergent fiber,and water-soluble carbohydrates).Conclusions These findings indicate that ELPs are abundant in the rumen and play a synergistic role in lignocellulosic biomass conversion.
基金supported by the Guangdong Special Support ProgramProject(No.2021JC060580)the Foshan Innovation Team Project(No.2130218003140).
文摘In this study,the effects of different salinity gradients and addition of compatible solutes on anaerobic treated effluent water qualities,sludge characteristics and microbial communities were investigated.The increase in salinity resulted in a decrease in particle size of the granular sludge,which was concentrated in the range of 0.5-1.0 mm.The content of EPS(extracellular polymeric substances)in the granular sludge gradually increased with increasing salinity and the addition of betaine(a typical compatible solute).Meanwhile,the microbial community structure was significantly affected by salinity,with high salinity reducing the diversity of bacteria.At higher salinity,Patescibacteria and Proteobacteria gradually became the dominant phylum,with relative abundance increasing to 13.53%and 12.16%at 20 g/L salinity.Desulfobacterota and its subordinate Desulfovibrio,which secrete EPS in large quantities,dominated significantly after betaine addition.Their relative abundance reached 13.65%and 7.86%at phylum level and genus level.The effect of these changes on the treated effluent was shown as the average chemical oxygen demand(COD)removal rate decreased from 82.10%to 79.71%,78.01%,68.51%and 64.55%when the salinity gradually increased from 2 g/L to 6,10,16 and 20 g/L.At the salinity of 20 g/L,average COD removal increased to 71.65%by the addition of 2 mmol/L betaine.The gradient elevated salinity and the exogenous addition of betaine played an important role in achieving stability of the anaerobic system in a highly saline environment,which provided a feasible strategy for anaerobic treatment of organic saline wastewater.
基金This work was supported by the DGAPA-UNAM(PAPIIT project,No.IN102721)the support from CONAHCYT through the Investigadoras e Investigadores por Mexico program(Researcher ID 6407,Project 265).
文摘Anaerobic oxidation of methane(AOM)can contribute to reducing methane emissions in landfills;however,the AOM rates vary depending on the inoculum source.This study addressed the capacity of AOM of a fermentative microbial community derived from a reactor treatingmunicipal solidwastes.First,the inoculum’s autotrophic capacitywas verified using a gasmixture of 75% CO_(2) and 25% H_(2).Results demonstrated that the fermentative microbial community reached amaximum CO_(2) consumption rate of 22.5±1.2 g CO_(2)/(m^(3)·h),obtaining acetate as the main product.Then,the inoculum was grown on a gas mixture of 50%CH_(4),35%CO_(2),and 15%N_(2),using iron(Fe^(3+))as the electron acceptor.The AOM rates increased over time and peaked at 3.1±0.9 g CH_(4)/(m^(3)·h)by 456 h with the simultaneous consumption of CO_(2).Acetate was the main product,with amaximum concentration of 180±9mg/L.By 408 h,a bacterial cluster of indicator species correlated with the AOM rates,including to Rhodobactereceae(r=0.80),Oceanicola(r=0.80),Propionicicella(r=0.77),Christensenellaceae(r=0.58),Oscillospiraceae(r=0.53),Mobilitalea(r=0.66),Hungateiclostridiaceae(r=0.46),and Izemoplasmatales(r=0.77).Methanosarcina,Methanobacterium,and Methanoculleus correlated with the AOM and CO_(2) consumption rates.A co-occurrence network analysis showed that Methanosarcina positively interacted with syntrophic bacteria like Christensenellaceae and Acinetobacter and diverse heterotrophic bacteria.This study demonstrated the feasibility of obtaining a CH_(4)-oxidizing microbial community in 16 days,exhibiting AOM rates higher than those reported for soils.
基金supported by grants from the National Basic Research Program of China(973 Program,nos.2012CB518501 and 2006CB504501)National Natural Science Foundation of China(no.81973941,no.81202741)State Scholarship Fund(no.201608320044).
文摘Acupuncture is used worldwide to treat migraine,but its scientific mechanism remains unclear.Here,we report a 1H NMR metabolomics study involving 40 migraine patients and 10 healthy individuals randomly receiving acupuncture or sham acupuncture,followed by machine learning techniques and functional analysis.We found that acupuncture at acupoints particularly enhanced anaerobic glycolysis and modified mitochondrial function by adjusting the levels of plasma pyruvic acid(p=0.012),lactic acid(p=0.031)and citrate(p=0.00079)at a Bonferroni-corrected level of significance compared to the pre-treatment level of these three metabolites in migraine patients.Therefore,acupuncture supplies energy to migraine patients and relieves migraine attacks.In contrast,we observed that sham acupuncture may partially supply energy to migraine patients through lipid metabolism by changing the levels of plasma lipid(p=0.0012),glycerine(p=0.021),and pyruvic acid(p=0.047)at a Bonferroni-corrected level of significance.The functional network analysis further indicates this different way of supplying energy contributes to the different effects of acupuncture and sham acupuncture.Our find-ings reveal novel metabolic evidence for the specific effect of acupuncture in relation to sham acupuncture.This metabolic evidence could enlighten a brand new direction into acupuncture analgesia mechanism,which in turn would pose fresh challenges for future acupuncture research.
基金Supported by the China Postdoctoral Science Foundation(2021M700742)Heilongjiang Postdoctoral Fund(LBH–Z21109)。
文摘Manure slurry application to farmland reduces chemical fertilizer use,mitigates pollution,and improves soil fertility.However,researches on the role of anaerobically treated cow slurry applied to soil microorganisms in Northeast China remain underexplored.Here,in laboratory incubation experiments,different treatments including various combinations of sterilized and non-sterilized soil and slurry,and different application rates were employed to examine the effects of indigenous microorganisms on soil microbial communities.Field-collected soil samples were employed to examine the responses and spatial variations of soil microbes under production conditions.The results indicated that indigenous soil microorganisms exerted a dominant influence in the microbial community variations,while the impact of cow slurry microbiota on community diversity was relatively minor.At the phylum level,Proteobacteria(P=0.031,R=0.969)showed a significant positive correlation with the slurry application,whereas Acidobacteriota(P=0.012,R=–0.988)and Basidiomycota(P=0.01,R=–0.99)showed significant negative correlations.In the field environment,the autumn slurry application effects on soil microbes in the following year were not significant.In contrast,under spring slurry application,the cow slurry-soil agglomerations led to significant spatial differences in soil microbial communities,with higher microbial diversity observed in the vicinity of agglomerations.The microbes in agglomerations,such as Actinomycetes,Bacteroides and Proteobacteria,were found to be beneficial for the crop residue decomposition.These microorganisms could decompose organic compounds including lignin,cellulose,hemicellulose,and xylan in crop straw.Overall,slurry application indeed influenced soil microbes and induced spatial variations,providing insights for sustainable agricultural practices.
基金supported by National Key Research and Development Program of China(2021YFD1300302)the National Natural Science Foundation of China(U23A20216 and 32372905)。
文摘Background Coumarins are toxic phytochemicals found in a variety of plants and are known to limit microbial degradation and interfere with nutrient cycling.While the degradation of coumarins by fungi has been studied in an environmental context,little is known about their degradation in the gastrointestinal system of herbivores after ingestion.Results In this study,we investigated in vitro fermentation by microbial enrichment,transcriptome sequencing,and high-resolution mass spectrometry to evaluate the ability of rumen anaerobic fungi to degrade coumarins.The results showed that despite the low abundance of anaerobic fungi in the rumen microbiota,they were able to effectively degrade coumarins.Specifically,Pecoramyces ruminantium F1 could tolerate coumarin concentrations up to 3 mmol/L and degrade it efficiently via metabolic pathways involving alpha/beta hydrolases and NAD(P)H oxidoreductases within the late growth phase.The fungus metabolized coumarin to less toxic compounds,including o-coumaric acid and melilotic acid,highlighting the detoxification potential of anaerobic fungi.Conclusions This study is the first to demonstrate the ability of rumen anaerobic fungi to degrade coumarin,providing new insights into the use of anaerobic fungi in sustainable agricultural practices and environmental detoxification strategies.
基金supported by the National Key Research and Development Program of China(2023YFC2412600)the National Natural Science Foundation of China(52271243,52171233,82370924,82170929)+3 种基金the Beijing Natural Science Foundation(L212014)the Beijing Nova Program(20230484459)the National Clinical Key Discipline Construction Project(PKUSSNKP-T202103)the Research Foundation of Peking University School and Hospital of Stomatology(PKSS20230104).
文摘Peri-implantitis is a bacterial infection that causes soft tissue inflammatory lesions and alveolar bone resorption,ultimately resulting in implant failure.Dental implants for clinical use barely have antibacterial properties,and bacterial colonization and biofilm formation on the dental implants are major causes of peri-implantitis.Treatment strategies such as mechanical debridement and antibiotic therapy have been used to remove dental plaque.However,it is particularly important to prevent the occurrence of peri-implantitis rather than treatment.Therefore,the current research spot has focused on improving the antibacterial properties of dental implants,such as the construction of specific micro-nano surface texture,the introduction of diverse functional coatings,or the application of materials with intrinsic antibacterial properties.The aforementioned antibacterial surfaces can be incorporated with bioactive molecules,metallic nanoparticles,or other functional components to further enhance the osteogenic properties and accelerate the healing process.In this review,we summarize the recent developments in biomaterial science and the modification strategies applied to dental implants to inhibit biofilm formation and facilitate bone-implant integration.Furthermore,we summarized the obstacles existing in the process of laboratory research to reach the clinic products,and propose corresponding directions for future developments and research perspectives,so that to provide insights into the rational design and construction of dental implants with the aim to balance antibacterial efficacy,biological safety,and osteogenic property.
文摘Anaerobic digestion(AD)is widely employed for sludge stabilization and waste reduction.However,the slow hydrolysis process hinders methane production and leads to prolonged sludge issues.In this study,an efficient and eco-friendly lysozyme pre-treatment method was utilized to address these challenges.By optimizing lysozyme dosage,hydrolysis and cell lysis were maximized.Furthermore,lysozyme combined with hydrothermal pretreatment enhanced overall efficiency.Results indicate that:(1)When lysozyme dosage reached 90 mg/g TS after 240 min of pretreatment,SCOD,soluble polysaccharides,and protein content reached their maxima at 855.00,44.09,and 204.86 mg/L,respectively.This represented an increase of 85.87%,365.58%,and 259.21%compared to the untreated sludge.Threedimensional fluorescence spectroscopy revealed the highest fluorescence intensity in the IV region(soluble microbial product),promoting microbial metabolic activity.(2)Lysozyme combined with hydrothermal pretreatment significantly increased SCOD,soluble proteins,and polysaccharide release from sludge,reducing SCOD release time.Orthogonal experiments identified Group 3 as the most effective for SCOD and soluble polysaccharide release,while Group 9 released the most soluble proteins.The significance order of factors influencing SCOD,soluble proteins,and polysaccharide release is hydrothermal temperature>hydrothermal time>enzymatic digestion time.(3)The lysozyme-assisted hydrothermal pretreatment group exhibited the fastest release and the highest SCOD concentration of 8,135.00 mg/L during anaerobic digestion.Maximum SCOD consumption and cumulative gas production increased by 95.89%and 130.58%,respectively,compared to the control group,allowing gas production to conclude 3 days earlier.
基金funded by the National Key Research and Development Program of China(2022YFA1304200)the Beijing Natural Science Foundation(6222032)the Starting Grants Program for Young Talents at China Agricultural University,the 2115 Talent Development Program of China Agricultural University,and Chinese Universities Scientific Fund.
文摘Probiotics have been demonstrated to be effective and safe for hyperuricemia(HUA)and gout treatment.Hence,identifying microbes with high uric acid-or purine-metabolizing ability is highly important.Due to the high load of uric acid in chicken feces,we hypothesized that the chicken gut would be an excellent source for new uric acid or purine-metabolizing microbes.In this study,we examined chicken gut contents to isolate an Enterococcus faecalis strain(designated CML390)that displayed high uric acid-degrading ability.In vitro experiments indicated that E.faecalis CML390 could effectively metabolize uric acid under both aerobic and anaerobic conditions,and the richer the nutrients,the higher the rate of uric acid degradation.By integrating genomics,transcriptomics,and metabolomics analyses,we revealed two pathways involved in aerobic and anaerobic uric acid degradation,respectively,in this isolate.E.faecalis CML390 relies on oxygen to metabolize uric acid into substances such as allantoin under aerobic conditions,while it also harbors a conserved uric acid-inducible gene cluster for anaerobic uric acid metabolism.An in vivo experiment showed that gavage with live E.faecalis CML390 in a mouse model of HUA(established using a combination of uric acid and potassium oxonate)significantly reduced serum uric acid levels and alleviated HUA.Our findings contribute to the exploration of the pathways and mechanisms of uric acid metabolism in intestinal microorganisms and provide a candidate probiotic for the treatment of HUA and gout.
基金supported by grants from the National Natural Science Foundation of China(Nos.42272356,92251304)the Kunlun Talented People of Qinghai Province,High-End Innovation and Entrepreneurship talents(Grant to Jiang Hongchen)+4 种基金the Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes(the Science and Technology Plan Project of Qinghai Province Incentive Fund,No.2024-KFKTA08)the 111 Program(the State Administration of Foreign Experts Affairs&the Ministry of Education of China,No.B18049)the Second Tibetan Plateau Scientific Expedition and Research Program(Polymenakou et al.)(No.2019QZKK0805)the Science and Technology Plan Project of Qinghai Province(No.2022-ZJ-Y08)Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)。
文摘Global warming and human activities have reduced the concentrations of dissolved oxygen in the bottom water of lakes,resulting in increased anoxia in surface sediments.This increased anoxia likely alters carbon cycling processes(e.g.,organic carbon mineralization)by altering microbial community composition and functions in lakes.However,it remains unclear how organic carbon mineralization responds to increased anoxia in surface sediments of lakes(particularly saline lakes).In this study,CO_(2)production in surface sediments of six lakes with different salinity(0.47-250 g/L)on the Tibetan Plateau was investigated using microcosm incubations under aerobic and anaerobic conditions,respectively,followed by geochemical and microbial analyses.The results showed that for the freshwater lake,CO_(2)production rates in anaerobic sediment microcosms were significantly(P<0.05)lower than their aerobic counterparts.In contrast,an opposite trend was observed for CO_(2)production in saline lakes.Furthermore,the CO_(2)production rates decreased significantly(P<0.05)under aerobic conditions,while it exhibited a hump-like relationship with increasing salinity under anaerobic conditions.Taken together,our results suggest that increased anoxia would enhance organic carbon mineralization in surface sediments of saline lakes and help understand carbon feedback on global changes in saline lakes.
基金Sponsored by Power China Eco-Environment Group Technology Project (Grant No.ST-ZB-ZC-JY-JS-2022-25)Heilongjiang Key Research and Development Program (Grant No.GA21C025)+1 种基金Technological Project of Heilongjiang Province"the open competition mechanism to select the best candidates"Foundation of National Local Joint Engineering Research Center for Biomass Energy Development and Utilization (Grant No.2021B006).
文摘The Anaerobic Digestion Model No.1(ADM1)has been modified to include enhanced kinetic parameters,which more precisely simulate methane production during the anaerobic digestion of diverse organic solid wastes.Calibration and validation of the model were achieved using experimental data from batch fermentation processes.Simulations of the updated ADM1 were conducted using AQUASIM 2.0 software.Sensitivity analysis helped identify and assess the most critical kinetic parameters affecting biogas production.Key parameters such as the microorganism decay constant(d^(-1)),disintegration rate constant(d^(-1)),Monod maximum specific substrate uptake rate(gCOD/gVSS·d),and half⁃saturation constants were found to significantly influence biogas yield.The optimal values for these parameters were identified as 0.03,6.07,3.64,and 0.27,respectively.These optimized values were validated through batch experiments.The modified ADM1 successfully predicted methane production,achieving R2 values greater than 0.8 in all validation trials.Key methanogens,Methanosarcina and Methanosaeta,were identified,and their enrichment during mixed fermentation of various organic solid wastes indicated enhanced methane production via aceticlastic methanogenesis.The microbial characterization and simulations using the modified ADM1 model supported each other.
基金supported by the National Key Research and Development Programme of China(No.2023YFC3206903)the Natural Science Foundation of China(No.51938010)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX23_1717).
文摘Red anaerobic ammonia oxidation (Anammox) granular sludge (AnGS) has been reported insuccessfully operating Anammox systems, and its color is associated with sludge activity.However, in long-term operating systems, AnGS exhibits different sensory colors, physicalstructures, community structures, and denitrification performance, but the relationship betweenthem has not yet been elucidated.The AnGS of the Anammox system, which has beenin operation for more than a decade, can be divided into twomain categories: red and white.The specific Anammox activity (SAA) in conventional red AnGS increased continuously asthe particle size increased from <0.51 mm to 6.02 ± 0.84 mm. The SAA of white AnGS wereslightly lower than those of red AnGS with similarly-size granules but significantly higherthan AnGS with smaller red granules. Compared with red AnGS, the extracellular polymericsubstances of white AnGS were significantly reduced,mainly due to the higher intracellulariron content, resulting in lower heme c concentration. Thus, heme c may prove not to bean evaluative tool for measuring Anammox activity. Red and white AnGS, whether throughself-aggregation or adsorption by hydroxyl apatite and other carriers, will face the fate ofinternal voids during particle size growth. White AnGS exhibited amore complex microbialcommunity than red AnGS. Candidatus Brocadia was abundant in red AnGS and the abundanceincreased with increasing granule size. Candidatus Kuenenia and Candidatus Jetteniamade significant contributions to denitrification in white AnGS. This study provides a newperspective on particle selection for anammox engineering applications.
基金supported by the Director General,Indian Council of Agricultural Research(ICAR),New Delhithe Director,ICAR-National Rice Research Institute,Cuttack.
文摘Consecutive stresses,such as initial submergence during germination followed by water deficit during the seedling stage,pose significant challenges to direct-seeded rice cultivation.By Linkage disequilibrium analysis,Sub1 and Dro1(Δbp:10 Mb),as well as Sub1 and TPP7(Δbp:6 Mb)were identified to exhibit long-range linkage disequilibrium(LRLD).Meta-QTL analysis further revealed that Sub1 and TPP7 co-segregated for tolerance to submergence at the germination and seedling stages.Based on this,we hypothesized that LRLD might influence plant responses to consecutive stresses.To test this hypothesis,we developed a structured recombinant inbred line population from a cross between Bhalum 2 and Nagina 22,with alleles(Sub1 and TPP7)in linkage equilibrium.Mendelian randomization analysis validated that the parental alleles,rather than the recombinant alleles of Sub1 and TPP7,significantly influenced 13 out of 41 traits under consecutive stress conditions.Additionally,16 minor additive effect QTLs were detected between the genomic regions,spanning Sub1 and TPP7 for various traits.A single allele difference between these genomic regions enhanced crown root number,root dry weight,and specific root area by 11.45%,15.69%,and 33.15%,respectively,under flooded germination conditions.Candidate gene analysis identified WAK79 and MRLK59 as regulators of stress responses during flooded germination,recovery,and subsequent water deficit conditions.These findings highlight the critical role of parental allele combinations and genomic regions between Sub1 and TPP7 in regulating the stress responses under consecutive stresses.Favourable haplotypes derived from these alleles can be utilized to improve stress resilience in direct-seeded rice.
基金supported by the National Key Research and Development Project (Nos.2020YFC1908702 and 2021YFC3200700)the National Natural Science Foundation of China (Nos.52192684 and 52192680).
文摘Sewage sludge in cities of Yangzi River Belt,China,generally exhibits a lower organic content and higher silt contentdue to leakage of drainage system,which caused low bioenergy recovery and carbon emission benefits in conventional anaerobic digestion(CAD).Therefore,this paper is on a pilot scale,a bio-thermophilic pretreatment anaerobic digestion(BTPAD)for low organic sludge(volatile solids(VS)of 4%)was operated with a long-term continuous flow of 200 days.The VS degradation rate and CH_(4) yield of BTPAD increased by 19.93%and 53.33%,respectively,compared to those of CAD.The analysis of organic compositions in sludge revealed that BTPAD mainly improved the hydrolysis of proteins in sludge.Further analysis of microbial community proportions by high-throughput sequencing revealed that the short-term bio-thermophilic pretreatment was enriched in Clostridiales,Coprothermobacter and Gelria,was capable of hydrolyzing acidified proteins,and provided more volatile fatty acid(VFA)for the subsequent reaction.Biome combined with fluorescence quantitative polymerase chain reaction(PCR)analysis showed that the number of bacteria with high methanogenic capacity in BTPAD was much higher than that in CAD during the medium temperature digestion stage,indicating that short-term bio-thermophilic pretreatment could provide better methanogenic conditions for BTPAD.Furthermore,the greenhouse gas emission footprint analysis showed that short-term bio-thermophilic pretreatment could reduce the carbon emission of sludge anaerobic digestion system by 19.18%.
基金supported by the National Key R&D Program of China(No.2022YFC2105301)the National Natural Science Foundation of China(No.52270096).
文摘Microbial consortia that catalyze chain elongation processes have been enriched using different selection strategies,for which the electron donor is an essential one.Propanol is an extraordinarily promising electron donor because it can be generated from renewable resources,including lignocellulosic biomass and protein wastes.Here,propanol was proven in detail to be an efficient electron donor,enhancing the production of odd medium-chain carboxylates during chain elongation.By exploring various electron acceptors,reactor conditions,and electron donor/electron acceptor mol ratios,our study highlights that acetate is the most suitable electron acceptor for the production of both odd-and even-chain carboxylates.The optimal conditions for propanol-based chain elongation were 30℃ and pH 6,achieving 82.8%selectivity for odd-chain carboxylates.Another critical insight from our work is that a propanol/acetate mol ratio of 1:1 can minimize the inhibitory effect of propanol and maximize the yield of medium-chain carboxylates,with the highest concentration of n-heptanoate reaching 124.5 mmol C/L.This was further illustrated by 16S rRNA amplicon sequencing,which elucidated that the community composition and keystone species in a propanol-based reactor closely resembled that of the ethanol one.The dominant phylum of the propanol-based reactor,Firmicutes showed a significant positive correlation with the concentrations of n-caproate and n-valerate.Additionally,the co-occurrence of Clostridium sensu stricto 12 and Oscillibacter,known as typical chain elongators,was identified within the propanol-based reactor.These findings enhance our understanding of propanolbased chain elongation,offer guiding principles for reactor microbiota assembly,and support efficient odd medium-chain carboxylate production.
基金supported by the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2023C03149).
文摘Anaerobic fermentation is an efficient method to extract phosphorus from excess sludge,thereby facilitating its recovery and mitigating the phosphorus resource shortage.However,the prevalent metal-bound phosphorus species within sludge was difficult to release into the fermentation liquor.To address this,this study evaluated the enhanced phosphorus release performance from sludge containing iron-phosphorus compounds(Fe-P)via co-fermenting it with agriculture wastes.Specifically,protein-rich feather(Feather Group)and polysaccharide-rich tea residue(Tea Group)was respectively dosed into batch-scale fermentation jar.Results showed that the Feather Group exhibited significantly higher levels of released soluble phosphorus(2.1 folds)and volatile fatty acids(41.4 folds)compared to the Control Group,with concentrations reaching up to 280 mg/L and 9366 mg chemical oxygen demand/L,respectively.The activities ofα-glucosidase,neutral protease and acetate kinase in the Feather group were increased by 11.1%,92.3%and 37.6%,respectively,compared with the Control group.Methanogen abundance decreased while hydrolytic acid-producing bacteria and iron-reducing bacteria increased significantly after supplying agricultural wastes.Metagenomic analysis demonstrated a significant increase in genes related to acetic acid synthesis.Mechanism elucidation suggested that increased iron-reducing bacteria abundance promoted Fe3+reduction into Fe2+,thus enhancing phosphorus release from Fe-P compounds.This work may provide valuable information for developing effective strategy to extract phosphorus resource from complex environmental wastes.
基金supported by the National Natural Science Foundation of China(Grants No.52270155 and 92047201).
文摘Cresyl diphenyl phosphate(CDP),an emerging aryl organophosphate ester(OPE),exhibits potential toxic effects and is frequently found in diverse environmental media,thereby raising concerns about environmental pollution.Biodegradation demonstrates substantial potential for CDP removal from the environment.This study investigated the biodegradation mechanisms of CDP using anaerobic activated sludge(AnAS).The biodegradation of 1-mg/L CDP followed a first-order kinetic model with a degradation kinetic constant of 0.943 d^(-1),and the addition of different electron acceptors affected the degradation rate.High-resolution mass spectrometry identified seven transformation products(TPs)of CDP.The pathways of CDP degradation in anaerobic conditions were proposed,with carboxylation products being the most dominant intermediate products.The structure of the anaerobic microbial community at different degradation time points in CDP-amended microcosms was examined.The linear discriminant analysis(LDA)of effect size(LEfSe)potentially underscored the pivotal role of Methyloversatilis in CDP biodegradation.Zebrafish embryotoxicity experiments revealed both lethal and morphogenetic impacts of CDP on zebrafish embryos.The survival rate,hatching rate,and body length indicators of zebrafish embryos underscored the detoxification of CDP and its resultant intermediates by AnAS.This study offers new insights into the fate and biodegradation mechanisms of CDP in wastewater treatment plants.
基金supported by the National Natural Science Foundation of China(No.52270018).
文摘The organic matter inmunicipal wastewater can be recovered by anaerobic biological treatment,making further resource utilization of municipal wastewater,which meets the requirements of sustainable development.An upflow anaerobic biofilter(UAF)treating municipal wastewater was established.The performances of stable operation and recovery operation of UAF after long-term starvation(234 days)and the changes of microbial community structure were researched.By gradually reducing HRT from 10 h to 4 h,the UAF achieved the treatment performance of pre-starvation after only 50 days recovery operation,in which total COD and soluble COD removal efficiencies reached 66%and 69%,respectively,and the CH_(4) production rate was 0.21 L CH_(4)/g CODremoval.The recovery performance of UAF after long term starvation showed that the recovery sequence of three main anaerobic processes was hydrolytic acidification,hydrogen-acetate production and methanogenesis.High-throughput sequencing results indicated that dominant bacteria associated with hydrolytic acidification process changed from Moduliflexaceae and Trichococcus in stable operation stage to Trichococcus and Romboutsia in recovery stage.Besides,the dominant archaea changed from Methanosaeta(hydrotrophic methanogens)to Methanobacterium(acetotrophic methanogens),showing Methanobacterium was more resistant to starvation environment.Therefore,by using UAF for biological treatment of organic matter,even after a long period of starvation,the system would not be completely destroyed.Once it resumed operation,the treatment performance could be restored in a short period of time.
