To better monitor the vertical crustal movements and sea level changes around Greenland,multiple data sources were used in this paper,including global positioning system(GPS),tide gauge,satellite gravimetry,satellite ...To better monitor the vertical crustal movements and sea level changes around Greenland,multiple data sources were used in this paper,including global positioning system(GPS),tide gauge,satellite gravimetry,satellite altimetry,glacial isostatic adjustment(GIA).First,the observations of more than 50 GPS stations from the international GNSS service(IGS)and Greenland network(GNET)in 2007–2018 were processed and the common mode error(CME)was eliminated with using the principal component analysis(PCA).The results show that all GPS stations show an uplift trend and the stations in southern Greenland have a higher vertical speed.Second,by deducting the influence of GIA,the impact of current Gr IS mass changes on GPS stations was analysed,and the GIA-corrected vertical velocity of the GPS is in good agreement with the vertical velocity obtained by gravity recovery and climate experiment(GRACE).Third,the absolute sea level change around Greenland at 4 gauge stations was obtained by combining relative sea level derived from tide gauge observations and crustal uplift rates derived from GPS observations,and was validated by sea level products of satellite altimetry.The results show that although the mass loss of Gr IS can cause considerable global sea level rise,eustatic movements along the coasts of Greenland are quite complex under different mechanisms of sea level changes.展开更多
Biosynthesizing Au nanoparticles(AuNPs)from gold-bearing scraps provides a sustainable method to meet the urgent demand for AuNPs.However,it remains challenging to efficiently biosynthesize AuNPs of which the diameter...Biosynthesizing Au nanoparticles(AuNPs)from gold-bearing scraps provides a sustainable method to meet the urgent demand for AuNPs.However,it remains challenging to efficiently biosynthesize AuNPs of which the diameter is less than 10 nm from a trace amount of Au^(3+)concentration at the level of tens ppm.Here,we constructed an exoelectrogenic cell(eCell)-conductive reduced-graphene-oxide aero-gel(rGA)biohybrid by assembling Shewanella sp.S1(SS1)as living biocatalyst and rGA as conductive ad-sorbent,in which Au^(3+)at trace concentrations would be enriched by the adsorption of rGA and reduced to AuNPs through the extracellular electron transfer(EET)of SS1.To regulate the size of the synthe-sized AuNPs to 10 nm,the strain SS1 was engineered to enhance its EET,resulting in strain RS2(pYYD-P tac-ribADEHC&pHG13-P_(bad)-omcC in SS1).Strain RS2 was further assembled with rGA to construct the RS2-rGA biohybrid,which could synthesize AuNPs with the size of 7.62±2.82 nm from 60 ppm Au^(3+)so-lution.The eCell-rGA biohybrid integrated Au^(3+)adsorption and reduction,which enabled AuNPs biosyn-thesis from a trace amount of Au^(3+).Thus,the required Au^(3+)ions concentration was reduced by one or two orders of magnitude compared with conventional methods of AuNPs biosynthesis.Our work devel-oped an AuNPs size regulation technology via engineering eCell’s EET with synthetic biology methods,providing a feasible approach to synthesize AuNPs with controllable size from trace level of gold ions.展开更多
In order to explore the composition and metabolic characteristics of functional microorganisms in the extreme environment of fermentation process, lactic acid was used as the sole carbon source in this study, and a st...In order to explore the composition and metabolic characteristics of functional microorganisms in the extreme environment of fermentation process, lactic acid was used as the sole carbon source in this study, and a strain of mold named JP8 was screened from fermented grains with soy sauce flavor. The 18S rDNA of JP8 and similar species were used to construct adjacent trees with MEGA 7.0.26. JP8 was the closest to Galactomyces geotrichum LMA-75, and the 18S rDNA sequence similarity of the two strains reached 99.52%. Therefore, JP8 was named G. geotrichum JP8. The highest growth temperature of JP8 is 35℃, the highest tolerance volume concentration to ethanol is 1.5%, and the highest tolerance volume concentration to lactic acid is 3%. JP8 can still grow well in PDA medium with pH 1. JP8 is fermented in a liquid fermentation medium with lactic acid as the sole carbon source to produce flavor substances such as acetic acid and propylene glycol.展开更多
The influence of stacking fermentation on pit fermentation is multifaceted in the Maotai flavor Baijiu(MFB).However,the influence and contribution degree of stacking fermentation on pit fermentation have not been full...The influence of stacking fermentation on pit fermentation is multifaceted in the Maotai flavor Baijiu(MFB).However,the influence and contribution degree of stacking fermentation on pit fermentation have not been fully clarified,and microbial community(MC)assembly modes in the heap and pit have not been clearly defined.Based on the analysis of the microbial community structure of stacking and pit fermentations,it was found that 60.82%of the bacteria and 49.07% of the fungi in the pit originated from the heap.Additionally,all the dominant microorganisms in the pit were also derived from the heap.Moreover,the bacterial contribution degree of the heap was generally higher than that of the fungi,and their contribution degrees to the microorganisms in the pit reached the highest at 3rd and 4th rounds,which were 84.81%and 71.88%,respectively.Furthermore,the volatile compounds of heap fermented grains had a relatively high contribution degree to the accumulation of alcohols,fatty acids and aromatic compounds in the pit.Meanwhile,environmental factors drove Thermomonas and Byssochlamys to construct MC in the heap,while drove Wickerhamomyces and Sphingomonas for constructing the MC of the pit.Finally,the MC assembly of the heap and pit both took the random assembly process as the predominant one.The bacterial community of the heap and pit were mainly assembled by the non-dominant process(64.43%,52.61%),while the fungal community of the heap and pit fermented grains were mainly assembled by the non-dominant process(47.96%)and the dispersal limitation assembly(43.48%),respectively.This work clearly clarified the influence and contribution degree of stacking fermentation on pit fermentation,and revealed the MC assembly modes of heap and pit fermented grains,offering significant practical implications for optimizing the fermentation quality of MFB.展开更多
Microbial community has an important impact on the whole brewing system and flavor formation during the pit fermentation of soy sauce flavor Baijiu(SFB).However,the spatiotemporal structure and succession of microbial...Microbial community has an important impact on the whole brewing system and flavor formation during the pit fermentation of soy sauce flavor Baijiu(SFB).However,the spatiotemporal structure and succession of microbial communities in the pit fermented grains,as well as the key habitat factors driving microbial community assembly at different spatial locations,are still unclear.In this study,we were the first to comprehensively analyze the similarities and differences in the microbial community structure and succession of pit surface,middle and bottom during the 1-7 rounds of pit fermentation.The fungalα-diversity of pit surface was the lowest,while the bacterialα-diversity was the highest in the pit surface.There were significant spatiotemporal differences in the distribution of dominant microorganisms during different rounds of pit surface,middle and bottom,and the types of dominant bacterial genera in the pit middle and bottom are more diverse than those in the pit surface.Most biomarkers(Streptococcus,Planifolium,etc.)of pit surface showed aerobic characteristics,while most bio-markers(Comamonas,Trichomonascus,etc.)of pit middle and bottom are anaerobic microorganisms.Further-more,the content of titratable acidity,starch and pH were the key driving factors for the assembly of microbial communities in the pit surface,middle and bottom,respectively.The dominant bacterial genera of pit surface,middle and bottom mainly promote microbial growth metabolism,other secondary metabolism and nucleoside metabolism,respectively,leading to differences in the growth enrichment and secondary metabolism of mi-crobial community in the pit fermented grains.This work comprehensively revealed the spatiotemporal differ-ences of microbial community structure and succession,and corresponding environmental driving factors during the 1-7 rounds of pit fermentation of SFB,providing scientific guidance for regulating the microbial community structure and high-level production in the brewing process of SFB.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
Blueberry wine presents a novel and promising alternative to traditional grape wines,with its pronounced freshness,floral,and fruity aroma being particularly appealing to consumers.However,the key aroma-active compoun...Blueberry wine presents a novel and promising alternative to traditional grape wines,with its pronounced freshness,floral,and fruity aroma being particularly appealing to consumers.However,the key aroma-active compounds responsible for its freshness-associated aroma were unclear.This study determined the characteristics of aroma compounds among eighteen blueberry wine samples(including seven commercial blueberry wines and eleven lab-brewed blueberry wines)by sensomics.A total of 132 aroma compounds were quantified by two-dimensional gas chromatography and time-of-flight mass spectrometry.Gas chromatographyolfactometry and odor activity values indicated that 31 aroma-active compounds were the major aroma contributors in blueberry wines.Orthogonal partial least squares-discriminant analysis results showed that freshness demonstrates a positive correlation with floral,and isopentanol,linalool,geraniol,β-myrcene andβ-damascone exhibited a positive correlation with freshness aroma attributes.The recombination,omission and addition tests clarified that linalool and geraniol contributed to the freshness attribute most.Whereas ethyl 2-methylbutyrate,ethyl 2-furoate and LIMETOL are aging markers,they do not directly cause freshness decline.This study provides important reference information to further enhance the blueberry wine's quality and appeal.展开更多
The fermentation of sauce-flavor Baijiu requires high-temperature Daqu as the starter,which is classified into three types:white,yellow,and black.Recent studies highlighted the variability of the microbiota and metab-...The fermentation of sauce-flavor Baijiu requires high-temperature Daqu as the starter,which is classified into three types:white,yellow,and black.Recent studies highlighted the variability of the microbiota and metab-olome profiles of these three types of Daqu,however,what functions they precisely provide in the sauce-flavor Baijiu brewing process remains unclear.In this study,white,yellow,and black Daqu in five different proportions were utilized as starters in field-scale Baijiu fermentation,with the control group lacking Daqu inoculation.Fermented grains inoculated with 100%white Daqu(47.7℃)had the highest temperature during stacking fermentation,while 100%black Daqu and control groups were lower than 45℃.Lactic acid(12.6-22.0 mg/g)was the most abundant organic acid,followed by acetic acid(0.7-5.0 mg/g).qPCR analysis revealed that bac-terial biomass decreased during fermentation,while fungal biomass increased.A comparison with the control revealed that Daqu contributed high-temperature resistant microorganisms to the stacking fermentation process,primarily Kroppenstedtia,Virgibacillus,Byssochlamys,Thermoascus,and Thermomyces.Meanwhile,stacking fermentation promoted the enrichment of Acetobacter,Kazachstania,and Leiothecium.Mantel test and co-occurrence network analysis revealed that utilizing different fermentation starters could vary the biotic and abiotic factors that drive microbial community succession.We investigated the flavor of Baijiu further,and found that fermentation with white Daqu enhanced the accumulation of ethyl acetate,isoamyl alcohol,and isobutanol,whereas black Daqu increased the accumulation of ethyl lactate,lactic acid,and furfural.This study contributes to the rational usage of different types of Daqu in the manufacturing of Baijiu.展开更多
基金The National Key R&D Program of China under contract No.2016YFC1402701the National Natural Science Foundation of China under contract Nos 41941010,41531069 and 41476162
文摘To better monitor the vertical crustal movements and sea level changes around Greenland,multiple data sources were used in this paper,including global positioning system(GPS),tide gauge,satellite gravimetry,satellite altimetry,glacial isostatic adjustment(GIA).First,the observations of more than 50 GPS stations from the international GNSS service(IGS)and Greenland network(GNET)in 2007–2018 were processed and the common mode error(CME)was eliminated with using the principal component analysis(PCA).The results show that all GPS stations show an uplift trend and the stations in southern Greenland have a higher vertical speed.Second,by deducting the influence of GIA,the impact of current Gr IS mass changes on GPS stations was analysed,and the GIA-corrected vertical velocity of the GPS is in good agreement with the vertical velocity obtained by gravity recovery and climate experiment(GRACE).Third,the absolute sea level change around Greenland at 4 gauge stations was obtained by combining relative sea level derived from tide gauge observations and crustal uplift rates derived from GPS observations,and was validated by sea level products of satellite altimetry.The results show that although the mass loss of Gr IS can cause considerable global sea level rise,eustatic movements along the coasts of Greenland are quite complex under different mechanisms of sea level changes.
基金supported by the National Key Research and Development Program of China(No.2018YFA0901300)the Na-tional Natural Science Foundation of China(Nos.NSFC 32071411,NSFC 32001034,and NSFC 31701569)+1 种基金the Young Science and Tech-nology Talents Growth Project of Education Department of Guizhou Province(No.KY[2018]445)Key Laboratory of Wuliangye-flavor Liquor Solid-state Fermentation,China National Light Indus-try(No.2021JJ013).
文摘Biosynthesizing Au nanoparticles(AuNPs)from gold-bearing scraps provides a sustainable method to meet the urgent demand for AuNPs.However,it remains challenging to efficiently biosynthesize AuNPs of which the diameter is less than 10 nm from a trace amount of Au^(3+)concentration at the level of tens ppm.Here,we constructed an exoelectrogenic cell(eCell)-conductive reduced-graphene-oxide aero-gel(rGA)biohybrid by assembling Shewanella sp.S1(SS1)as living biocatalyst and rGA as conductive ad-sorbent,in which Au^(3+)at trace concentrations would be enriched by the adsorption of rGA and reduced to AuNPs through the extracellular electron transfer(EET)of SS1.To regulate the size of the synthe-sized AuNPs to 10 nm,the strain SS1 was engineered to enhance its EET,resulting in strain RS2(pYYD-P tac-ribADEHC&pHG13-P_(bad)-omcC in SS1).Strain RS2 was further assembled with rGA to construct the RS2-rGA biohybrid,which could synthesize AuNPs with the size of 7.62±2.82 nm from 60 ppm Au^(3+)so-lution.The eCell-rGA biohybrid integrated Au^(3+)adsorption and reduction,which enabled AuNPs biosyn-thesis from a trace amount of Au^(3+).Thus,the required Au^(3+)ions concentration was reduced by one or two orders of magnitude compared with conventional methods of AuNPs biosynthesis.Our work devel-oped an AuNPs size regulation technology via engineering eCell’s EET with synthetic biology methods,providing a feasible approach to synthesize AuNPs with controllable size from trace level of gold ions.
文摘In order to explore the composition and metabolic characteristics of functional microorganisms in the extreme environment of fermentation process, lactic acid was used as the sole carbon source in this study, and a strain of mold named JP8 was screened from fermented grains with soy sauce flavor. The 18S rDNA of JP8 and similar species were used to construct adjacent trees with MEGA 7.0.26. JP8 was the closest to Galactomyces geotrichum LMA-75, and the 18S rDNA sequence similarity of the two strains reached 99.52%. Therefore, JP8 was named G. geotrichum JP8. The highest growth temperature of JP8 is 35℃, the highest tolerance volume concentration to ethanol is 1.5%, and the highest tolerance volume concentration to lactic acid is 3%. JP8 can still grow well in PDA medium with pH 1. JP8 is fermented in a liquid fermentation medium with lactic acid as the sole carbon source to produce flavor substances such as acetic acid and propylene glycol.
基金supported by National Natural Science Foundation of China(32460269)Guizhou Provincial Basic Research Program(Natural Science)key project(QianKeHeJiChu-ZD[2025]018)+3 种基金Moutai Institute&Guizhou Guiding distillery cooperation research and development project(XYNJ20240374)Guizhou Provincial Science and Technology Projects of China([2020]1Y144)the Fund of Zunyi Technology and Big data Bureau,Moutai institute Joint Science and Technology Research and Development Project(ZunShiKeHe HZ Zi[2023]108&[2023]374)Research Foundation for Scientific Scholars of Moutai Institute(mygccrc[2022]034,mygccrc[2022]133,mygccrc[2022]017,mygccrc[2024]001).
文摘The influence of stacking fermentation on pit fermentation is multifaceted in the Maotai flavor Baijiu(MFB).However,the influence and contribution degree of stacking fermentation on pit fermentation have not been fully clarified,and microbial community(MC)assembly modes in the heap and pit have not been clearly defined.Based on the analysis of the microbial community structure of stacking and pit fermentations,it was found that 60.82%of the bacteria and 49.07% of the fungi in the pit originated from the heap.Additionally,all the dominant microorganisms in the pit were also derived from the heap.Moreover,the bacterial contribution degree of the heap was generally higher than that of the fungi,and their contribution degrees to the microorganisms in the pit reached the highest at 3rd and 4th rounds,which were 84.81%and 71.88%,respectively.Furthermore,the volatile compounds of heap fermented grains had a relatively high contribution degree to the accumulation of alcohols,fatty acids and aromatic compounds in the pit.Meanwhile,environmental factors drove Thermomonas and Byssochlamys to construct MC in the heap,while drove Wickerhamomyces and Sphingomonas for constructing the MC of the pit.Finally,the MC assembly of the heap and pit both took the random assembly process as the predominant one.The bacterial community of the heap and pit were mainly assembled by the non-dominant process(64.43%,52.61%),while the fungal community of the heap and pit fermented grains were mainly assembled by the non-dominant process(47.96%)and the dispersal limitation assembly(43.48%),respectively.This work clearly clarified the influence and contribution degree of stacking fermentation on pit fermentation,and revealed the MC assembly modes of heap and pit fermented grains,offering significant practical implications for optimizing the fermentation quality of MFB.
基金supported by Guizhou Provincial Science and Technology Projects of China(ZK[2021 general 093]),the Fund of Zunyi Technology and Big data Bureau,Moutai institute Joint Science and Technology Research and Development Project(ZunShiKeHe HZ Zi[2023]108,[2021]305)+1 种基金Research Foundation for Scientific Scholars of Moutai Institute(mygccrc[2022]005)Moutai Institute&Guangzhou YueHui Cosmetics Co.,Ltd.cooperation research and development project(XYNJ20230089).
文摘Microbial community has an important impact on the whole brewing system and flavor formation during the pit fermentation of soy sauce flavor Baijiu(SFB).However,the spatiotemporal structure and succession of microbial communities in the pit fermented grains,as well as the key habitat factors driving microbial community assembly at different spatial locations,are still unclear.In this study,we were the first to comprehensively analyze the similarities and differences in the microbial community structure and succession of pit surface,middle and bottom during the 1-7 rounds of pit fermentation.The fungalα-diversity of pit surface was the lowest,while the bacterialα-diversity was the highest in the pit surface.There were significant spatiotemporal differences in the distribution of dominant microorganisms during different rounds of pit surface,middle and bottom,and the types of dominant bacterial genera in the pit middle and bottom are more diverse than those in the pit surface.Most biomarkers(Streptococcus,Planifolium,etc.)of pit surface showed aerobic characteristics,while most bio-markers(Comamonas,Trichomonascus,etc.)of pit middle and bottom are anaerobic microorganisms.Further-more,the content of titratable acidity,starch and pH were the key driving factors for the assembly of microbial communities in the pit surface,middle and bottom,respectively.The dominant bacterial genera of pit surface,middle and bottom mainly promote microbial growth metabolism,other secondary metabolism and nucleoside metabolism,respectively,leading to differences in the growth enrichment and secondary metabolism of mi-crobial community in the pit fermented grains.This work comprehensively revealed the spatiotemporal differ-ences of microbial community structure and succession,and corresponding environmental driving factors during the 1-7 rounds of pit fermentation of SFB,providing scientific guidance for regulating the microbial community structure and high-level production in the brewing process of SFB.
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supported by Guizhou Provincial Science and Technology Projects of China(ZK[2024 general 658])National Nature Science Foundation Project(32372261)+3 种基金Major Science and Technology Projects in Shaanxi Province(2024NC-BSLD-01)Corps Science and Technology Programme Projects(2024AB042)Research Foundation for Scientific Scholars of Moutai Institute(mygccrc[2022]025)Research Foundation for Scientific Scholars of Moutai Institute(mygccrc[2022]060).
文摘Blueberry wine presents a novel and promising alternative to traditional grape wines,with its pronounced freshness,floral,and fruity aroma being particularly appealing to consumers.However,the key aroma-active compounds responsible for its freshness-associated aroma were unclear.This study determined the characteristics of aroma compounds among eighteen blueberry wine samples(including seven commercial blueberry wines and eleven lab-brewed blueberry wines)by sensomics.A total of 132 aroma compounds were quantified by two-dimensional gas chromatography and time-of-flight mass spectrometry.Gas chromatographyolfactometry and odor activity values indicated that 31 aroma-active compounds were the major aroma contributors in blueberry wines.Orthogonal partial least squares-discriminant analysis results showed that freshness demonstrates a positive correlation with floral,and isopentanol,linalool,geraniol,β-myrcene andβ-damascone exhibited a positive correlation with freshness aroma attributes.The recombination,omission and addition tests clarified that linalool and geraniol contributed to the freshness attribute most.Whereas ethyl 2-methylbutyrate,ethyl 2-furoate and LIMETOL are aging markers,they do not directly cause freshness decline.This study provides important reference information to further enhance the blueberry wine's quality and appeal.
基金supported by the Research Foundation for Scientific Scholars of Moutai Institute(mygccrc[2022]012).
文摘The fermentation of sauce-flavor Baijiu requires high-temperature Daqu as the starter,which is classified into three types:white,yellow,and black.Recent studies highlighted the variability of the microbiota and metab-olome profiles of these three types of Daqu,however,what functions they precisely provide in the sauce-flavor Baijiu brewing process remains unclear.In this study,white,yellow,and black Daqu in five different proportions were utilized as starters in field-scale Baijiu fermentation,with the control group lacking Daqu inoculation.Fermented grains inoculated with 100%white Daqu(47.7℃)had the highest temperature during stacking fermentation,while 100%black Daqu and control groups were lower than 45℃.Lactic acid(12.6-22.0 mg/g)was the most abundant organic acid,followed by acetic acid(0.7-5.0 mg/g).qPCR analysis revealed that bac-terial biomass decreased during fermentation,while fungal biomass increased.A comparison with the control revealed that Daqu contributed high-temperature resistant microorganisms to the stacking fermentation process,primarily Kroppenstedtia,Virgibacillus,Byssochlamys,Thermoascus,and Thermomyces.Meanwhile,stacking fermentation promoted the enrichment of Acetobacter,Kazachstania,and Leiothecium.Mantel test and co-occurrence network analysis revealed that utilizing different fermentation starters could vary the biotic and abiotic factors that drive microbial community succession.We investigated the flavor of Baijiu further,and found that fermentation with white Daqu enhanced the accumulation of ethyl acetate,isoamyl alcohol,and isobutanol,whereas black Daqu increased the accumulation of ethyl lactate,lactic acid,and furfural.This study contributes to the rational usage of different types of Daqu in the manufacturing of Baijiu.
