Bacterial Diversity During Brewing Processes Of Traditional Vinegar By High-throughput Sequencing

The development history of vinegar in China can be traced back to thousands of years ago.The brewing technology has been very mature after continuous improvement.Vinegar in Shanxi province of China is brewed by traditional solid-state brewing technology.It adopts solid-state raw material and solid-state Daqu fermentation technology,and both solid-state raw material and solid-state Daqu contain abundant microorganisms,which play an important role in the whole fermentation process.At present,there is little research on microbial diversity in the traditional vinegar brewing process.This paper uses according to the different stages of traditional vinegar brewing,17 groups of 51 samples were collected from Shanxi Changzhi Shengtang vinegar Co.,Ltd.Some of the physical and chemical properties of these samples were tested,and the bacterial diversity in the whole brewing process was analyzed by DNA high throughput sequencing technique.The main results obtained are as follows:(1)During the whole brewing process,the moisture content was the least(25.87%)in Daqu and the highest(75.5%)in the stage of high temperature fumigation;with the development of fermentation,the temperature of titratable acid and fermented grain in fermentative tank increased slowly,up to 40.5 ?.The highest p H value was raw material5.33 and the second was vinegar 4.55.The p H value of other samples fluctuated between 3.52 and 3.97.(2)A total of 2647375 valid sequences,including 863 OTUs,were obtained by high-throughput sequencing.During the whole brewing process,the composition of bacterial community was constantly changing.The main bacterial communities in raw materials are Lactobacillus,Weissella and Leuconostoc;Acinetobacter and Lactobacillus in Daqu;Lactobacillus and Acetobacter during fermentation;Weissella,Lactobacillus,Vibrio and Ralstonia in fumigation vinegar stage;Lactobacillus,Acetobacter and Acinetobacter in gonorrhea stage.(3)In the process of traditional vinegar brewing,the fermentation period is 46 days.In the prophase of fermentation,alcoholic fermentation is mainly carried out.The dominant bacteria are Lactobacillus and Westerella,the species richness of which is higher than 80%.In the later period of fermentation,the dominant bacteria are Lactobacillus and Acetobacter,the ricity can reach 97.2%.(4)During the fermentation stage,there were 355 bacterial OTU,of which 288 OTU came from Daqu and raw materials,accounting for81.1% of the total bacterial OTU in fermentation stage.The bacterial communities in the traditional vinegar brewing process were mainly derived from raw materials and Daqu.The remaining 18.8% comes from the environment,tools,air,etc.