Study On The Bacterial Community Structure In Fermentation Of Maotai-flavor Liquor

Various stages of fermentation of raw materials involved in Maotai liquor fermentation process were selected, including Mao-tai flavor starter, fermented grains (upper, middle, lower), pit mud, and accumulated fermented grains. The microbial communities in samples of different liquor fermentation stages were investigated by traditional microbiological culture, the Biolog method, phospholipids fatty acids (PLFAs) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). From the results of the traditional culture method, we found the microbial number in each stage of the liquor fermentation differed significantly. The population of micro-organisms was in order as follows:Mao-tai flavor starter>accumulated fermented grains> fermented grains. Differences were also observed in different fermented liquor layers:pit mud> upper>middle>lower (CFU). Microbes such as molds, yeasts, and bacterial diversified in each stage of the liquor fermentation. With analysis by the Biolog method we observed the microbial activity in samples of different liquor fermentation stages increased with the prolonged incubation time. By using PLFAs, research liquor fermentation samples, experiment detected from the sample30kinds of PLFAs between C14～C22were detected in the samples of different liquor fermentation stages, of which16:00,16:lw7c,18:00were detected in all the sample, suggesting they were the fermentation dominant strains. The results of the PCR-DGGE bacterial microbial community structure showed that the microbial community structure in the samples differed apparently. There were still more yet to be known micro-organisms after bands determination, which also illustrated that direct analysis lof the total DNA in fermentation samples based on non-culture molecular biology techniques helped the discovery of new microbial species. Except uncultured bacteria the bacterial community in the14fermented grain samples could be classified mainly belonging to the Bacillaceae of Firmicutes, including the Lactobacillaceae of Lactobacillales, Bacillaceae of Bacillales, of which the Lactobacillus played predominant.