Study On The Microbial Community Structure In The Brewing Environment Of Maotai-flavor Liquor

Chinese liquor brewing process is a complex spontaneous solid state fermentation process driven by diverse microorganisms.Its brewing yield and quality are closely related to the fermentation environment.The unique stacking process in the production of Maotai-flavor liquor can make grains snare up and enrich microorganisms in the environment of brewing workshop,which is called "secondary Daqu-making".Therefore,it is of great significance to study the environmental microorganisms in the brewing workshop for understanding the brewing mechanism and production characteristics of Maotai-flavor liquor and solving production problems.However,there is no systematic study on the community structure of environmental microbiota of the Maotai-flavor liquor.The research on microorganisms in Maotai-flavor liquor mainly focused on Daqu and fermented grains,but relatively few on environmental microorganisms.In this study,high-throughput sequencing methods were used to systematically explore the characteristics and differences of microbial community structure in different brewing Areasand different fermentation rounds of Maotai-flavor liquor.The main research results are as follows:1.A total of 23 phylum and 561 genus of bacteria,4 phylum and 212 genus of fungi were detected in all environmental samples from seven brewing Areas in Maotai Town throughout the year(seven fermentation rounds).There were 16 common phylum and 235 common genus of bacteria,4 common phylum and 63 common genus of fungi in seven Areas.At the level of phylum and genus,common microorganisms predominated in all Areas(the sum of relative abundance were more than 97.10 %),particular microorganisms were unevenly distributed and rich in species(5.88 %~61.59 % of the total microorganisms in each Area),however,the sum of relative abundance were relatively small(less than 2.9 %).There were 17 common phylum and 280 common genus of bacteria,4 common phylum and 56 common genus of fungi in seven fermentation rounds.At the level of phylum and genus,Common microorganisms predominated in all fermentation rounds(the sum of relative abundance were more than 96.75 %),particular microorganisms were unevenly distributed and rich in species(0 %~58.50 % of the total microorganisms in each fermentation rounds),however,the sum of relative abundance were relatively small(less than 3.25 %).2.The dominant bacteria phylum in the seven brewing Areas of Maotai Town(average relative abundance greater than 1%)were Proteobacteria?Firmicutes?Bacteroidetes and Actinobacteria.Ascomycota was the first dominant fungal phylum in all Areas,and Basidiomycota was the second dominant fungal phylum.The common dominant bacteria genus in the seven brewing Areas of Maotai Town were Sphingobacterium?Enterobacter?Pantoea?unclassified_f__Enterobacteriaceae?Acinetobacter?Pseudomonas?Kroppenstedtia?Lentibacillus,and the common dominant fungal genus in the seven brewing Areas of Maotai Town were Wallemia?Saccharomycopsis?Wickerhamomyces?Aspergillus?Thermoascus?unclassified_f__Saccharomycetaceae.The dominant bacteria phylum in the seven fermentation rounds of Maotai Town were Proteobacteria?Firmicutes?Bacteroidetes and Actinobacteri,Proteobacteria was the first dominant bacteria phylum in all fermentation rounds.There was no dominant phylum in each fermentation round.Ascomycota was the first dominant fungal phylum in the first to fourth fermentation rounds.Basidiomycota was the first dominant fungal phylum in the fifth to seventh fermentation rounds.The common dominant bacteria genus in the seven fermentation rounds were Sphingobacterium?Enterobacter?Pantoea?unclassified_f__Enterobacteriaceae?Acinetobacter?Pseudomonas?Escherichia-Shigella and Weissella,and the common dominant fungal genus in the seven fermentation rounds were Saccharomycopsis and Aspergillus.3.At the OTU level,the diversity and richness of microbial communities in different Areas were quite different.Area2 and Area4 were significantly higher than Area5 and Area7;The diversity and richness of microbial communities in different fermentation rounds were very small.There were significant differences in diversity of bacterial community and richness of fungal community only between the sixth andthe seventh fermentation rounds.The diversity and richness of microbial communities were the lowest in the seventh fermentation rounds.At the phylum level,the distribution of bacterial community was different among different Areas,but the difference was small(42.86% of the bacterial phylum had significant difference,the sum of relative abundance were 21.70%~46.05%).There was no significant difference in fungi.The distribution of bacterial community was different among different fermentation rounds,but the difference was small(37.5 %of the bacterial phylum had significant difference,the sum of relative abundance were65.99 %~79.65 %).And the difference of fungi was large(75 % of the fungal phylum had significant difference,the sum of relative abundance were 99.92 %~99.99 %).At the genus level,the distribution of microbial community was different among different Areas,but the difference was small(25 % of the bacterial phylum had significant difference,the sum of relative abundance were 16.42 %~42.02 %;34.78 %of the fungal phylum had significant difference,the sum of relative abundance were23.24 %~71.20 %).The distribution of bacterial community was different among different fermentation rounds,but the difference was small(21.05 % of the bacterial genus had significant difference,the sum of relative abundance were16.83 %~29.04 %).And the difference of fungi was large(91.30 % of the fungal phylum had significant difference,the sum of relative abundance were62.99 %~94.08 %).