Cereals are an important part of staple foods all over the world,and their fermentation is an age-old technique to obtain desired food products.Cereal-based foods have been widely consumed for thousands of years as a ...Cereals are an important part of staple foods all over the world,and their fermentation is an age-old technique to obtain desired food products.Cereal-based foods have been widely consumed for thousands of years as a major source of nutrients,particularly in developing and overpopulated countries,and in Africa they represent a major source of nutrients and energy.Thus,the main aim of this review is a focus on cereal-based and fermented foods from Africa,with a special emphasis on the most important keywords and topics of the literature,microbiota,as well as on the nutritional side,to provide evidence on the importance of these products as sources of functional microorganisms,and/or starter cultures.展开更多
Tibetan Qula,a traditional fermented food processed from yak milk,is valued for its high nutritional content and distinctive flavor,but the vast territory of Xizang often results in quality heterogeneity.To identify t...Tibetan Qula,a traditional fermented food processed from yak milk,is valued for its high nutritional content and distinctive flavor,but the vast territory of Xizang often results in quality heterogeneity.To identify the core microorganisms with metabolic activities in Qula,we conducted a comprehensive investigation of 10 samples from 7 regions of Xizang using integrated multi-omics techniques and multivariate statistical analysis.All samples were higher in protein content(36.43-60.25%),acidity(86.72-216.52°T)and lactic acid bacteria count(3.69-6.14 logCFU/g),while lower in fat(2.40-11.35%)and moisture contents(5.84-12.02%).High-throughput sequencing showed significant differences in microbial diversity and community composition among samples,but Lactococcus,Lactobacillus,Leuconostoc,Acetobacter,Penicillium and Aspergillus were core microorganisms due to their high abundance and wide distribution.Notably,they also played an important role in maintaining community interactions,especially Acetobacter.Of the 60 volatiles detected by GC-MS,23 compounds such as hexanal,heptanal,butanoic acid,hexanoic acid and ethyl octanoate were identified as the dominant flavors.In contrast,the 62 non-volatiles obtained from metabolomics were primarily composed of carbohydrates,organic acids,fatty acids and amino acids,with lactose,lactic acid,palmitic acid and alanine being the most abundant metabolites in their respective categories.Correlation analysis indicated that core microorganisms were predominantly involved in the formation and transformation of metabolites,while Lactococcus,Rhodotorula and Trichothecium facilitated the accumulation of various flavors.This study provides a comprehensive analysis of the microbial and metabolic characteristics of Tibetan Qula,offering a scientific foundation for quality enhancement through biofortification technology.展开更多
Jiuqu,a saccharification and fermentation agent used in the production of baijiu,is rich in enzymes,microorganisms,and organisms that have essential effects on the flavor quality of baijiu.However,traditional Jiuqu ha...Jiuqu,a saccharification and fermentation agent used in the production of baijiu,is rich in enzymes,microorganisms,and organisms that have essential effects on the flavor quality of baijiu.However,traditional Jiuqu has some deficiencies in quality or may require enhancement of specific functions at times.To address this,fortified Jiuqu has been developed and applied to enhance performance and improve baijiu quality.This review focused on the functional microorganisms and strengthening effects of fortified Jiuqu.Moreover,this review also discussed the limitations of current Jiuqu preparation and fortification and explored the roles of the core functional microbes and the synthetic microflora for fortified Jiuqu,which could improve the cleanliness,controllability,and food safety of Jiuqu production.展开更多
Soil metaproteomics has excellent potential as a tool to elucidate the structural and functional changes in soil microbial communities in response to environmental alterations. However, soil metaproteomics is hindered...Soil metaproteomics has excellent potential as a tool to elucidate the structural and functional changes in soil microbial communities in response to environmental alterations. However, soil metaproteomics is hindered by several challenges and gaps. Soil microbial communities possess extremely complex microbial composition, including many uncultured microorganisms without whole genome sequencing. Thus, how to select a suitable protein sequence database remains challenging in soil metaproteomics. In this study, the Public database and Meta-database were constructed using protein sequences from public databases and metagenomics, respectively. We comprehensively analyzed and compared the soil metaproteomic results using these two kinds of protein sequence databases for protein identification based on published soil metaproteomic raw data. The results demonstrated that many more proteins, higher sequence coverage, and even more microbial species and functional annotations could be identified using the Meta-database compared with those identified using the Public database. These findings indicated that the Meta-database was more specific as a protein sequence database. However, the follow-up in-depth metaproteomic analyses exhibited similar main results regardless of the database used. The microbial community composition at the genus level was similar between the two databases, especially the species annotations with high peptide-spectrum match and high abundance. The functional analyses in response to stress, such as the gene ontology enrichment of biological progress and molecular function and the key functional microorganisms, were also similar regardless of the database. Our analysis revealed that the Public database could also meet the demand to explore the functional responses of microbial proteins to some extent. This study provides valuable insights into the choice of protein sequence databases and their impacts on subsequent bioinformatic analysis in soil metaproteomic research and will facilitate the optimization of experimental design for different purposes.展开更多
Moisture plays a pivotal role in solid-state fermentation by providing essential environmental support for microbial growth,regulating temperature and humidity,influencing metabolic efficiency,and ultimately controlli...Moisture plays a pivotal role in solid-state fermentation by providing essential environmental support for microbial growth,regulating temperature and humidity,influencing metabolic efficiency,and ultimately controlling the fermentation process.This study investigated the effects of moisture on microbial community diversity,functional microorganisms,and metabolic capacity during Daqu fermentation.A room environment monitoring system was developed to collect real-time environmental parameters,revealing moisture as a key driver of microbial community succession(p=0.001).Characteristic microorganisms,including Lichtheimia,Lactiplantibacillus,Pichia,Aspergillus,and Proteus,were identified.Structural equation modeling(SEM)analysis demonstrated that microbialα-diversity exhibited a significant positive correlation with moisture(p<0.01).While increased microbialα-diversity suppressed Lichtheimia and Aspergillus(p<0.05),it significantly promoted the proliferation of Lactiplantibacillus,Pichia,and Proteus(p<0.01).Lichtheimia showed a positive correlation with saccharifying power(p<0.05)and a highly significant positive correlation with esterifying power(p<0.01).The growth of Aspergillus significantly enhanced both saccharifying and liquefying powers of Daqu(p<0.01),whereas Lactiplantibacillus,Pichia,and Proteus markedly improved fermenting power(p<0.01).Metatranscriptomic analysis revealed the expression of key functional enzymes and their microbial origins,demonstrating that Lactiplantibacillus,Pichia,and Wickerhamomyces all contributed to saccharification,liquefaction,fermentation,and esterification.These findings provide both theoretical and practical insights into the influence of moisture on microbial metabolism and the optimization of fermentation processes.展开更多
Complex microbial metabolism is responsible for the unique flavor of soy sauce.In our earlier work,we unveiled the pivotal components that contribute to the unique flavor of soy sauce.However,it is challenging to comp...Complex microbial metabolism is responsible for the unique flavor of soy sauce.In our earlier work,we unveiled the pivotal components that contribute to the unique flavor of soy sauce.However,it is challenging to comprehend the connection between microbes and the development of flavors during soy sauce fermentation.This work aims to characterize the taxonomic and functional attributes of soy sauce fermentation microbiota as well as to validate it.Samples from three representative fermentation stages were selected for metagenomic sequencing.Results demonstrated that in the metabolic network linked to the characteristic flavor formation,the functional genes are primarily connected to the metabolism of carbohydrates and amino acids.Analysis of mi-crobial distribution in different flavor biosynthesis pathways revealed that 15 key genera were involved in the flavor generation.Finally,6 screened potential flavor-producing microorganisms were validated by culturing them in a simulated high-salt fermentation environment of soy sauce,with several strains demonstrating the ability to produce the characteristic flavor of soy sauce,and Weissella paramesenteroides being the most remarkable.These findings are helpful for the selection of flavor-inducing starters for soy sauce industrial fermentation.展开更多
The mechanized production of Baijiu is a significant trend,yet the shift from traditional brewing to controlled and efficient modern fermentation methods has not been fully accomplished.This study aimed to identify th...The mechanized production of Baijiu is a significant trend,yet the shift from traditional brewing to controlled and efficient modern fermentation methods has not been fully accomplished.This study aimed to identify the disparities in the microbial structure and metabolism of fermented grains among different heap fermentation modes and enhance mechanized box heap fermentation through the inoculation of microorganisms.Metagenomics was used to ascertain the differences between microbial communities and metabolic functions.In mechanized box heap fermentation,the dominant microorganisms included Saccharomyces cerevisiae(43.61%),Nakaseomyces glabrata(25.89%),Kroppenstedtia eburnean(9.22%).In traditional manual heap fermentation,the dominant microorganisms included Bacillus amyloliquefaciens(14.8%),Bacillus licheniformis(14.02%),and Bacillus sonorensis(9.77%).The dominant functional genes in box heap fermentation were K13953(for alcohol dehydrogenase;ADH)and K00844(for hexokinase;glk),while those in traditional manual heap fermentation were K00016(for lactate dehydrogenase;LDH)and K00158(for pyruvate oxidase;pox).Owing to their differential functions in box-fermented grains,inoculating brewing microorganisms can augment the saccharification reaction rate and content of flavor substances.This research offers support to effectively ameliorate the box heap fermentation and augment the heap fermentation efficiency of sauce-flavored liquor.展开更多
Hazardous levels of biogenic amines(BA)are frequently detected in soy sauce.However,the microorganisms and mechanisms responsible for BA formation in soy sauce are not well understood.In this study,we investigated the...Hazardous levels of biogenic amines(BA)are frequently detected in soy sauce.However,the microorganisms and mechanisms responsible for BA formation in soy sauce are not well understood.In this study,we investigated the dynamic changes and metabolic pathways of BAs during soy sauce fermentation via metabolome and metagenomic analyses.Spermidine and putrescine were the main BAs detected during koji making,while putrescine,tyramine,phenylethylamine,and histamine were dominant during moromi fermentation.PCA analysis revealed that the soy sauce fermentation process could be divided into five representative stages based on the dynamics of BAs.Metagenomic analysis uncovered that a total of 15 genera were mainly involved in BAs formation,particularly,histamine was principally produced by Klebsiella,and Bacillus was the major tyramine-synthesizing bacteria.Correlation analysis showed that pH increase inhibited the spermidine production during koji making,whereas elevated NaCl concentration facilitated the phenylethylamine formation during moromi fermentation.Co-occurrence network analysis unveiled the associations between the BA-producing microorganisms and other genera.Overall,these results have improved our understanding of the mechanism of BA formation during soy sauce fermentation and guided the development of fermentation agents capable of degrading BA in industrial manufacture soy sauce production.展开更多
Multispecies microbial mixed fermentation is crucial for the formation of flavors in soy sauce.The present study applied metagenomic strategies to uncover the metabolic network for flavors formation in the non-Cantone...Multispecies microbial mixed fermentation is crucial for the formation of flavors in soy sauce.The present study applied metagenomic strategies to uncover the metabolic network for flavors formation in the non-Cantonese soy sauce in China.Twenty-nine major flavor compounds were identified by GC-MS and HPLC,representing the typical flavor compounds of the non-Cantonese soy sauce,including 3 organic acids,8 amino acids,and 18 volatile compounds.Metagenomic sequencing and KEGG enrichment analysis revealed the specific functional microbiome,which constituted seven major flavor compounds associated genera,namely Leuconostoc,Staphylococcus,Tetragenococcus,Weissella,Aspergillus,Wickerhamycesa,and Zygosaccharomyces.Aspergillus was primarily responsible for the degradation of raw materials in the early fermentation stage,including the degradation of cellulose and lecithin.It also played an irreplaceable role in the formation of 1-octene-3-ol.Weissella,Staphylococcus,and Leuconostoc played essential metabolic roles in the whole fermentation process,particularly in the metabolism of amino acids and the formation of alcohols.Staphylococcus also participated in the degradation of nitrite/nitrate.Tetragenococcus became the dominant bacteria with the highest relative abundance in the late fermentation stage,which was mainly responsible for the synthesis of acetic acid,lactic acid,and other acids.Additionally,Wickerhamycesa and Zygosaccharomyces also contributed to the formation of alcohols,acids,and aldehydes during the late fermentation stage.This study provides a deeper understanding of the diverse roles in the flavor formation of microorganisms during the traditional condiment soy sauce fermentation process.展开更多
This study presented new insights into the sustainable conversion of total petroleum hydrocarbon(TPHC)into polyhydroxyalkanoates(PHAs)using wetland microbial fuel cells(WMFCs).The main innovations included the followi...This study presented new insights into the sustainable conversion of total petroleum hydrocarbon(TPHC)into polyhydroxyalkanoates(PHAs)using wetland microbial fuel cells(WMFCs).The main innovations included the following two points:(1)The integration of bioelectricity generation with efficient PHA production further underscored the potential of electroactive biofilms as a sustainable platform for simultaneous TPHC biotransformation,bioelectricity recovery and PHA production.(2)The interactive dynamics of PHAs,metabolites,extracellular polymeric substances(EPS)and microorganisms during the formation and stabilization of electroactive biofilms provided novel insights into microbial strategies for carbon utilization.As the electroactive biofilm formed and stabilized,the current density enhanced significantly from 0 to 101 mA m2,then stabilized,and finally dropped to 3.51 mA m2.Similarly,the power density showed a trend of increasing in the initial stage,maintaining in the middle stage,and then descending in the later stage.The production of six types of PHAs was identified:poly(3-hydroxybutyrate)[P(3HB)],poly(3-hydroxyvalerate)[P(3HV)],poly(3-hydroxybutyrate-co-3-hydroxyvalerate)[P(3HB-co-3HV)],poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate][P(3HB-co-3HHX)],poly(3-hydroxyhexadecanoate)[P(3HHD)]and poly(3-hydroxyoctadecanoate)[P(3HOD)],highlighting the metabolic flexibility of electroactive biofilms.The total PHA content was initially undetectable(days 0–4),gradually increased(days 4–28),rose rapidly(days 28–48),gradually increased and descended(days 48–68).The maximum PHA content of 0.664 g g⁻1 DCW achieved highlighted the dual functionality of WMFCs in bioelectricity production and PHA biosynthesis,distinguishing it from conventional MFC applications.The TPHC biodegradation ratio demonstrated a gradual increase(days 0–28),with a more pronounced rise(days 28–48),and a gradual rise to 76.1%(days 48–68).Throughout the process,the metabolite volatile fatty acids(VFAs)produced were primarily acetate,propionate,butyrate and valerate.The trend of VFA production from days 0–56 closely followed that of TPHC biodegradation.The trend of tyrosine/tryptophan proteins in EPS was aligned with that of biofilm thickness.The strong correlation between the increase in the biofilm thickness and the intensity and peak height of tyrosine/tryptophan proteins during the first 20 days suggested that these proteins were integral to the structural integrity of the biofilms,and from days 20–64,the minimal variation in their intensity and peak height indicated that the biofilms had reached a relatively stable state.The biofilms in turn provided a stable microbial substrate and energetic support for the subsequent efficient synthesis of PHA.During the early phase,the dual-function bacteria,such as Pseudomonas,Bacillus,Acinetobacter and Desulfosarcina,prioritized electron transfer and bioelectricity production using available carbon sources.As bioelectricity generation became less critical in the later phase,the bacteria shifted to intracellular PHA accumulation,transitioning from bioelectricity production to PHA biosynthesis.Finally,a comprehensive network connecting functional microorganisms with bioelectricity production,PHA content,TPHC biodegradation,VFA production and EPS peak height was established.Overall,these findings provided valuable insights into the dynamic interactions and metabolic strategies of electroactive biofilms in WMFCs,highlighting their potential for the efficient bioconversion of PHCs into PHAs.展开更多
Surfactants were expected to exhibit positive effects on the waste activated sludge(WAS)disposal.However,the systematic comparison of different categories of surfactants on the WAS fermentation and the functional mech...Surfactants were expected to exhibit positive effects on the waste activated sludge(WAS)disposal.However,the systematic comparison of different categories of surfactants on the WAS fermentation and the functional mechanisms,especially microbial metabolic traits,have not yet been precisely explored.This study revealed the positive effects of different surfactants on the volatile fatty acid(VFA)production,which followed the order of alkyl polysaccharides(APG)>sodium dodecylbenzene sulfonate(SDBS)>hexadecyl trimethyl ammonium bromide(HTAB).Mechanistic exploration found that the presence of different surfactants improved solubilization and hydrolysis steps,and then contributed to the subsequent acidification with different efficiencies.The functional microorganisms associated with VFA generation were enriched in surfactant-conditioned reactors.Metagenomic analysis further indicated that the key genes involved in the particular process of VFA generation were over-expressed.The simultaneous bioavailable substrate improvement,functional bacterial enrichment,and metabolic activity upregulation induced by different surfactants jointly contributed to VFA promotion during WAS fermentation.This study could provide a comprehensive realization of surfactants’impacts on theWAS fermentation process,and more importantly,it reminded the public to discern the distinct interplaying effects induced by different chemicals in regulating the WAS disposal and resource recovery.展开更多
Direct sewage discharge may enhance soil nitrous oxide(N_(2)O)emissions,worsening the greenhouse effect.However,the effects of sewage discharge into bogs on N_(2)O flux,drivers and influencing mechanisms remain unclea...Direct sewage discharge may enhance soil nitrous oxide(N_(2)O)emissions,worsening the greenhouse effect.However,the effects of sewage discharge into bogs on N_(2)O flux,drivers and influencing mechanisms remain unclear.Additionally,investigating the impact of reclaimed water on N_(2)O flux is important for bog replenishment and water shortage alleviation.This study simulated sewage from different sources into a bog and analyzed N_(2)O fluxes,soil(organic carbon,total nitrogen,ammonium nitrogen,nitrate nitrogen,total phosphorus,available phosphorus,pH and electrical conductivity),plant(species richness and biomass)and microorganisms(ammonia-oxidizing archaea,napA,nirS,nirK and nosZ genes).Results showed that the reclaimed water did not significantly change N_(2)O flux,while 50%tap water mixed with 50%domestic sewage and domestic sewage significantly increased the N_(2)O flux.Among soil factors,available nitrogen and pH were key in influencing N_(2)O flux.Among plant parameters,species richness was the primary factor affecting N_(2)O flux.Nitrogen transformation functional genes contributed the most to the increase in the N_(2)O fluxes,with an increase in domestic sewage input leading to a higher abundance of these genes and subsequent N_(2)O emissions.Therefore,domestic sewage should be considered,as it significantly increases N_(2)O emissions by affecting the soil,plants and microorganisms,thereby increasing the global warming potential.This study’s findings suggest that using treated reclaimed water for bog replenishment could be an environmentally friendly approach to wetland management.展开更多
Suansun is a Chinese fermented bamboo shoot product with unique stinky odor.In our previous,we have revealed the key aroma components that endowed the unique flavor of traditional suansun.However,the functional microb...Suansun is a Chinese fermented bamboo shoot product with unique stinky odor.In our previous,we have revealed the key aroma components that endowed the unique flavor of traditional suansun.However,the functional microbiota and how their metabolism affects flavor formation during suansun fermentation remained unclear.Thus,combined with results for the characteristic flavor substances formed during suansun fermentation in our previous study,samples from three representative stages during suansun fermentation were selected for metagenomic sequencing in this study,to understand the influence of microbial metabolism on the flavor formation of suansun.Results showed that the functional genes are mainly associated with carbohydrate metabolism and amino acid metabolism.Pyruvate and acetyl-coA were the key compounds in the whole microbial metabolic network,which promoted the conversion between different compounds.Analysis about distribution of microbes in different flavor biosynthesis pathways showed that ten genera,namely,Lactobacillus,Lactococcus,Leuconostoc,Clostridium,Enterobacter,Klebsiella,Kluyvera,Burkholderia,Leclercia,and Enterococcus,were the key microorganisms contributing to the production of main characteristic flavor substances of suansun.These results may contribute to novel insights into the functional microbial resources and might be helpful for the development of novel defined starter cultures to promote technological advances in the traditional suansun industry.展开更多
文摘Cereals are an important part of staple foods all over the world,and their fermentation is an age-old technique to obtain desired food products.Cereal-based foods have been widely consumed for thousands of years as a major source of nutrients,particularly in developing and overpopulated countries,and in Africa they represent a major source of nutrients and energy.Thus,the main aim of this review is a focus on cereal-based and fermented foods from Africa,with a special emphasis on the most important keywords and topics of the literature,microbiota,as well as on the nutritional side,to provide evidence on the importance of these products as sources of functional microorganisms,and/or starter cultures.
基金supported by Guizhou Provincial Science and Technology Projects(Qiankehe Jichu[2024]Youth 196,197)Youth Science and Technology Talent Development Project(Qianjiaoji[2024]265).
文摘Tibetan Qula,a traditional fermented food processed from yak milk,is valued for its high nutritional content and distinctive flavor,but the vast territory of Xizang often results in quality heterogeneity.To identify the core microorganisms with metabolic activities in Qula,we conducted a comprehensive investigation of 10 samples from 7 regions of Xizang using integrated multi-omics techniques and multivariate statistical analysis.All samples were higher in protein content(36.43-60.25%),acidity(86.72-216.52°T)and lactic acid bacteria count(3.69-6.14 logCFU/g),while lower in fat(2.40-11.35%)and moisture contents(5.84-12.02%).High-throughput sequencing showed significant differences in microbial diversity and community composition among samples,but Lactococcus,Lactobacillus,Leuconostoc,Acetobacter,Penicillium and Aspergillus were core microorganisms due to their high abundance and wide distribution.Notably,they also played an important role in maintaining community interactions,especially Acetobacter.Of the 60 volatiles detected by GC-MS,23 compounds such as hexanal,heptanal,butanoic acid,hexanoic acid and ethyl octanoate were identified as the dominant flavors.In contrast,the 62 non-volatiles obtained from metabolomics were primarily composed of carbohydrates,organic acids,fatty acids and amino acids,with lactose,lactic acid,palmitic acid and alanine being the most abundant metabolites in their respective categories.Correlation analysis indicated that core microorganisms were predominantly involved in the formation and transformation of metabolites,while Lactococcus,Rhodotorula and Trichothecium facilitated the accumulation of various flavors.This study provides a comprehensive analysis of the microbial and metabolic characteristics of Tibetan Qula,offering a scientific foundation for quality enhancement through biofortification technology.
基金partly supported by the Key R&D Programme of the Sichuan Province of China(2023YFS0484)the Solid-state Fermentation Resource Utilization Key Laboratory of Sichuan Province(2021GTYY04).
文摘Jiuqu,a saccharification and fermentation agent used in the production of baijiu,is rich in enzymes,microorganisms,and organisms that have essential effects on the flavor quality of baijiu.However,traditional Jiuqu has some deficiencies in quality or may require enhancement of specific functions at times.To address this,fortified Jiuqu has been developed and applied to enhance performance and improve baijiu quality.This review focused on the functional microorganisms and strengthening effects of fortified Jiuqu.Moreover,this review also discussed the limitations of current Jiuqu preparation and fortification and explored the roles of the core functional microbes and the synthetic microflora for fortified Jiuqu,which could improve the cleanliness,controllability,and food safety of Jiuqu production.
基金supported by the National Key Research and Development Program of China(No.2016YFD0200-308)the National Key Basic Research Program of China(No.2015CB150501)the Project of Priority and Key Areas,Institute of Soil Science,Chinese Academy of Sciences(Nos.ISSASIP1605 and ISSASIP1640).
文摘Soil metaproteomics has excellent potential as a tool to elucidate the structural and functional changes in soil microbial communities in response to environmental alterations. However, soil metaproteomics is hindered by several challenges and gaps. Soil microbial communities possess extremely complex microbial composition, including many uncultured microorganisms without whole genome sequencing. Thus, how to select a suitable protein sequence database remains challenging in soil metaproteomics. In this study, the Public database and Meta-database were constructed using protein sequences from public databases and metagenomics, respectively. We comprehensively analyzed and compared the soil metaproteomic results using these two kinds of protein sequence databases for protein identification based on published soil metaproteomic raw data. The results demonstrated that many more proteins, higher sequence coverage, and even more microbial species and functional annotations could be identified using the Meta-database compared with those identified using the Public database. These findings indicated that the Meta-database was more specific as a protein sequence database. However, the follow-up in-depth metaproteomic analyses exhibited similar main results regardless of the database used. The microbial community composition at the genus level was similar between the two databases, especially the species annotations with high peptide-spectrum match and high abundance. The functional analyses in response to stress, such as the gene ontology enrichment of biological progress and molecular function and the key functional microorganisms, were also similar regardless of the database. Our analysis revealed that the Public database could also meet the demand to explore the functional responses of microbial proteins to some extent. This study provides valuable insights into the choice of protein sequence databases and their impacts on subsequent bioinformatic analysis in soil metaproteomic research and will facilitate the optimization of experimental design for different purposes.
基金supported by grant from the Guannan County Finance Bureau,the National Natural Science Foundation of China(32302030)the China Postdoctoral Science Foundation(2023M731334).
文摘Moisture plays a pivotal role in solid-state fermentation by providing essential environmental support for microbial growth,regulating temperature and humidity,influencing metabolic efficiency,and ultimately controlling the fermentation process.This study investigated the effects of moisture on microbial community diversity,functional microorganisms,and metabolic capacity during Daqu fermentation.A room environment monitoring system was developed to collect real-time environmental parameters,revealing moisture as a key driver of microbial community succession(p=0.001).Characteristic microorganisms,including Lichtheimia,Lactiplantibacillus,Pichia,Aspergillus,and Proteus,were identified.Structural equation modeling(SEM)analysis demonstrated that microbialα-diversity exhibited a significant positive correlation with moisture(p<0.01).While increased microbialα-diversity suppressed Lichtheimia and Aspergillus(p<0.05),it significantly promoted the proliferation of Lactiplantibacillus,Pichia,and Proteus(p<0.01).Lichtheimia showed a positive correlation with saccharifying power(p<0.05)and a highly significant positive correlation with esterifying power(p<0.01).The growth of Aspergillus significantly enhanced both saccharifying and liquefying powers of Daqu(p<0.01),whereas Lactiplantibacillus,Pichia,and Proteus markedly improved fermenting power(p<0.01).Metatranscriptomic analysis revealed the expression of key functional enzymes and their microbial origins,demonstrating that Lactiplantibacillus,Pichia,and Wickerhamomyces all contributed to saccharification,liquefaction,fermentation,and esterification.These findings provide both theoretical and practical insights into the influence of moisture on microbial metabolism and the optimization of fermentation processes.
基金supported by Basic and Applied Basic Research Foundation of Guangdong Province(Project No.2021B1515120042)National Natural Science Foundation of China(Project No.32160547)+1 种基金Vegetable Industry Technology System Post Expert Project of Jiangxi Province(Project No.JXARS-06)Nanchang University High Value Patent Cultivation Program.
文摘Complex microbial metabolism is responsible for the unique flavor of soy sauce.In our earlier work,we unveiled the pivotal components that contribute to the unique flavor of soy sauce.However,it is challenging to comprehend the connection between microbes and the development of flavors during soy sauce fermentation.This work aims to characterize the taxonomic and functional attributes of soy sauce fermentation microbiota as well as to validate it.Samples from three representative fermentation stages were selected for metagenomic sequencing.Results demonstrated that in the metabolic network linked to the characteristic flavor formation,the functional genes are primarily connected to the metabolism of carbohydrates and amino acids.Analysis of mi-crobial distribution in different flavor biosynthesis pathways revealed that 15 key genera were involved in the flavor generation.Finally,6 screened potential flavor-producing microorganisms were validated by culturing them in a simulated high-salt fermentation environment of soy sauce,with several strains demonstrating the ability to produce the characteristic flavor of soy sauce,and Weissella paramesenteroides being the most remarkable.These findings are helpful for the selection of flavor-inducing starters for soy sauce industrial fermentation.
文摘The mechanized production of Baijiu is a significant trend,yet the shift from traditional brewing to controlled and efficient modern fermentation methods has not been fully accomplished.This study aimed to identify the disparities in the microbial structure and metabolism of fermented grains among different heap fermentation modes and enhance mechanized box heap fermentation through the inoculation of microorganisms.Metagenomics was used to ascertain the differences between microbial communities and metabolic functions.In mechanized box heap fermentation,the dominant microorganisms included Saccharomyces cerevisiae(43.61%),Nakaseomyces glabrata(25.89%),Kroppenstedtia eburnean(9.22%).In traditional manual heap fermentation,the dominant microorganisms included Bacillus amyloliquefaciens(14.8%),Bacillus licheniformis(14.02%),and Bacillus sonorensis(9.77%).The dominant functional genes in box heap fermentation were K13953(for alcohol dehydrogenase;ADH)and K00844(for hexokinase;glk),while those in traditional manual heap fermentation were K00016(for lactate dehydrogenase;LDH)and K00158(for pyruvate oxidase;pox).Owing to their differential functions in box-fermented grains,inoculating brewing microorganisms can augment the saccharification reaction rate and content of flavor substances.This research offers support to effectively ameliorate the box heap fermentation and augment the heap fermentation efficiency of sauce-flavored liquor.
基金supported by National Natural Science Foundation of China(Project No.32160547)Basic and Applied Basic Research Foundation of Guangdong Province(Project No.2021B1515120042)+2 种基金Vegetable Industry Technology System Post Expert Project of Jiangxi Province(Project No.JXARS-06)Jiangxi Provincial Key R&D Program(20232BBF60024)Jiangxi Provincial Agricultural Key Core Technology Tackling Issues(JXNK202303-05).
文摘Hazardous levels of biogenic amines(BA)are frequently detected in soy sauce.However,the microorganisms and mechanisms responsible for BA formation in soy sauce are not well understood.In this study,we investigated the dynamic changes and metabolic pathways of BAs during soy sauce fermentation via metabolome and metagenomic analyses.Spermidine and putrescine were the main BAs detected during koji making,while putrescine,tyramine,phenylethylamine,and histamine were dominant during moromi fermentation.PCA analysis revealed that the soy sauce fermentation process could be divided into five representative stages based on the dynamics of BAs.Metagenomic analysis uncovered that a total of 15 genera were mainly involved in BAs formation,particularly,histamine was principally produced by Klebsiella,and Bacillus was the major tyramine-synthesizing bacteria.Correlation analysis showed that pH increase inhibited the spermidine production during koji making,whereas elevated NaCl concentration facilitated the phenylethylamine formation during moromi fermentation.Co-occurrence network analysis unveiled the associations between the BA-producing microorganisms and other genera.Overall,these results have improved our understanding of the mechanism of BA formation during soy sauce fermentation and guided the development of fermentation agents capable of degrading BA in industrial manufacture soy sauce production.
基金the financial support from the Program of Introducing Talents of Discipline to Universities(111 Project)(111-2-06).
文摘Multispecies microbial mixed fermentation is crucial for the formation of flavors in soy sauce.The present study applied metagenomic strategies to uncover the metabolic network for flavors formation in the non-Cantonese soy sauce in China.Twenty-nine major flavor compounds were identified by GC-MS and HPLC,representing the typical flavor compounds of the non-Cantonese soy sauce,including 3 organic acids,8 amino acids,and 18 volatile compounds.Metagenomic sequencing and KEGG enrichment analysis revealed the specific functional microbiome,which constituted seven major flavor compounds associated genera,namely Leuconostoc,Staphylococcus,Tetragenococcus,Weissella,Aspergillus,Wickerhamycesa,and Zygosaccharomyces.Aspergillus was primarily responsible for the degradation of raw materials in the early fermentation stage,including the degradation of cellulose and lecithin.It also played an irreplaceable role in the formation of 1-octene-3-ol.Weissella,Staphylococcus,and Leuconostoc played essential metabolic roles in the whole fermentation process,particularly in the metabolism of amino acids and the formation of alcohols.Staphylococcus also participated in the degradation of nitrite/nitrate.Tetragenococcus became the dominant bacteria with the highest relative abundance in the late fermentation stage,which was mainly responsible for the synthesis of acetic acid,lactic acid,and other acids.Additionally,Wickerhamycesa and Zygosaccharomyces also contributed to the formation of alcohols,acids,and aldehydes during the late fermentation stage.This study provides a deeper understanding of the diverse roles in the flavor formation of microorganisms during the traditional condiment soy sauce fermentation process.
基金supported by National Natural Science Foundation of China(42106144)Natural Science Foundation of Shandong Province(ZR2021QE125,ZR2020QD089 and ZR2023QC207)+2 种基金Science and Technology Project of Beijing Life Science Academy Company Limited(0002023CC0090)Natural Science Foundation of Qingdao City(23-2-1-52-zyyd-jch)Central Public-interest Scientific Institution Basal Research Fund(1610232023020).
文摘This study presented new insights into the sustainable conversion of total petroleum hydrocarbon(TPHC)into polyhydroxyalkanoates(PHAs)using wetland microbial fuel cells(WMFCs).The main innovations included the following two points:(1)The integration of bioelectricity generation with efficient PHA production further underscored the potential of electroactive biofilms as a sustainable platform for simultaneous TPHC biotransformation,bioelectricity recovery and PHA production.(2)The interactive dynamics of PHAs,metabolites,extracellular polymeric substances(EPS)and microorganisms during the formation and stabilization of electroactive biofilms provided novel insights into microbial strategies for carbon utilization.As the electroactive biofilm formed and stabilized,the current density enhanced significantly from 0 to 101 mA m2,then stabilized,and finally dropped to 3.51 mA m2.Similarly,the power density showed a trend of increasing in the initial stage,maintaining in the middle stage,and then descending in the later stage.The production of six types of PHAs was identified:poly(3-hydroxybutyrate)[P(3HB)],poly(3-hydroxyvalerate)[P(3HV)],poly(3-hydroxybutyrate-co-3-hydroxyvalerate)[P(3HB-co-3HV)],poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate][P(3HB-co-3HHX)],poly(3-hydroxyhexadecanoate)[P(3HHD)]and poly(3-hydroxyoctadecanoate)[P(3HOD)],highlighting the metabolic flexibility of electroactive biofilms.The total PHA content was initially undetectable(days 0–4),gradually increased(days 4–28),rose rapidly(days 28–48),gradually increased and descended(days 48–68).The maximum PHA content of 0.664 g g⁻1 DCW achieved highlighted the dual functionality of WMFCs in bioelectricity production and PHA biosynthesis,distinguishing it from conventional MFC applications.The TPHC biodegradation ratio demonstrated a gradual increase(days 0–28),with a more pronounced rise(days 28–48),and a gradual rise to 76.1%(days 48–68).Throughout the process,the metabolite volatile fatty acids(VFAs)produced were primarily acetate,propionate,butyrate and valerate.The trend of VFA production from days 0–56 closely followed that of TPHC biodegradation.The trend of tyrosine/tryptophan proteins in EPS was aligned with that of biofilm thickness.The strong correlation between the increase in the biofilm thickness and the intensity and peak height of tyrosine/tryptophan proteins during the first 20 days suggested that these proteins were integral to the structural integrity of the biofilms,and from days 20–64,the minimal variation in their intensity and peak height indicated that the biofilms had reached a relatively stable state.The biofilms in turn provided a stable microbial substrate and energetic support for the subsequent efficient synthesis of PHA.During the early phase,the dual-function bacteria,such as Pseudomonas,Bacillus,Acinetobacter and Desulfosarcina,prioritized electron transfer and bioelectricity production using available carbon sources.As bioelectricity generation became less critical in the later phase,the bacteria shifted to intracellular PHA accumulation,transitioning from bioelectricity production to PHA biosynthesis.Finally,a comprehensive network connecting functional microorganisms with bioelectricity production,PHA content,TPHC biodegradation,VFA production and EPS peak height was established.Overall,these findings provided valuable insights into the dynamic interactions and metabolic strategies of electroactive biofilms in WMFCs,highlighting their potential for the efficient bioconversion of PHCs into PHAs.
基金The work is financially supported by the National Natural Science Foundation of China(Grant No.52070069)Fundamental Research Funds for the Central Universities(China)(No.B200202099)+3 种基金Jiangsu Province Natural Science Foundation(China)(BK20211207)Shanghai Post-doctoral Excellence Program(China)(No.2020419)China Postdoctoral Science Foundation(No.2021M692423)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(China)(No.PCRRF20005).
文摘Surfactants were expected to exhibit positive effects on the waste activated sludge(WAS)disposal.However,the systematic comparison of different categories of surfactants on the WAS fermentation and the functional mechanisms,especially microbial metabolic traits,have not yet been precisely explored.This study revealed the positive effects of different surfactants on the volatile fatty acid(VFA)production,which followed the order of alkyl polysaccharides(APG)>sodium dodecylbenzene sulfonate(SDBS)>hexadecyl trimethyl ammonium bromide(HTAB).Mechanistic exploration found that the presence of different surfactants improved solubilization and hydrolysis steps,and then contributed to the subsequent acidification with different efficiencies.The functional microorganisms associated with VFA generation were enriched in surfactant-conditioned reactors.Metagenomic analysis further indicated that the key genes involved in the particular process of VFA generation were over-expressed.The simultaneous bioavailable substrate improvement,functional bacterial enrichment,and metabolic activity upregulation induced by different surfactants jointly contributed to VFA promotion during WAS fermentation.This study could provide a comprehensive realization of surfactants’impacts on theWAS fermentation process,and more importantly,it reminded the public to discern the distinct interplaying effects induced by different chemicals in regulating the WAS disposal and resource recovery.
基金supported by the National Key R&D Program of China(2022YFF1300900)the National Natural Science Foundation of China(32271624)+1 种基金the Foundation of Jilin Scientifc and Technological Development Project(20220203003SF)the Education Department of Jilin Province(JJKH20230516KJ).
文摘Direct sewage discharge may enhance soil nitrous oxide(N_(2)O)emissions,worsening the greenhouse effect.However,the effects of sewage discharge into bogs on N_(2)O flux,drivers and influencing mechanisms remain unclear.Additionally,investigating the impact of reclaimed water on N_(2)O flux is important for bog replenishment and water shortage alleviation.This study simulated sewage from different sources into a bog and analyzed N_(2)O fluxes,soil(organic carbon,total nitrogen,ammonium nitrogen,nitrate nitrogen,total phosphorus,available phosphorus,pH and electrical conductivity),plant(species richness and biomass)and microorganisms(ammonia-oxidizing archaea,napA,nirS,nirK and nosZ genes).Results showed that the reclaimed water did not significantly change N_(2)O flux,while 50%tap water mixed with 50%domestic sewage and domestic sewage significantly increased the N_(2)O flux.Among soil factors,available nitrogen and pH were key in influencing N_(2)O flux.Among plant parameters,species richness was the primary factor affecting N_(2)O flux.Nitrogen transformation functional genes contributed the most to the increase in the N_(2)O fluxes,with an increase in domestic sewage input leading to a higher abundance of these genes and subsequent N_(2)O emissions.Therefore,domestic sewage should be considered,as it significantly increases N_(2)O emissions by affecting the soil,plants and microorganisms,thereby increasing the global warming potential.This study’s findings suggest that using treated reclaimed water for bog replenishment could be an environmentally friendly approach to wetland management.
基金supported by the National Natural Science Foundation of China(Project No.32160547)Vegetable Industry Technology System Post Expert Project of Jiangxi Province(Project No.JXARS-06)+1 种基金Ten major directions of Guangdong Agricultural Science and Technology Innovation in the 14th Five-Year Plan(Project No.2023SDZG04)Yunnan Key Laboratory of Fermented Vegetables:Science and Technology Talent and Platform Program(Project No.202205AG070001)are gratefully acknowledged.
文摘Suansun is a Chinese fermented bamboo shoot product with unique stinky odor.In our previous,we have revealed the key aroma components that endowed the unique flavor of traditional suansun.However,the functional microbiota and how their metabolism affects flavor formation during suansun fermentation remained unclear.Thus,combined with results for the characteristic flavor substances formed during suansun fermentation in our previous study,samples from three representative stages during suansun fermentation were selected for metagenomic sequencing in this study,to understand the influence of microbial metabolism on the flavor formation of suansun.Results showed that the functional genes are mainly associated with carbohydrate metabolism and amino acid metabolism.Pyruvate and acetyl-coA were the key compounds in the whole microbial metabolic network,which promoted the conversion between different compounds.Analysis about distribution of microbes in different flavor biosynthesis pathways showed that ten genera,namely,Lactobacillus,Lactococcus,Leuconostoc,Clostridium,Enterobacter,Klebsiella,Kluyvera,Burkholderia,Leclercia,and Enterococcus,were the key microorganisms contributing to the production of main characteristic flavor substances of suansun.These results may contribute to novel insights into the functional microbial resources and might be helpful for the development of novel defined starter cultures to promote technological advances in the traditional suansun industry.
