Changes of bacterial community and its metabolic characteristic in fermentation process of strong-flavor Baijiu fermented grains based on PacBio sequencing

Abstract

The bacterial community structure and its metabolic characteristic in the fermentation process of strong-flavor (Nongxiangxing) Baijiu fermented grains were analyzed using 16S rRNA gene full-length sequencing technology PacBio, and the correlation between bacterial bacterial and volatile flavor substances was also analyzed. The results revealed that the brewing process of strong-flavor Baijiu could be divided into a changing period (0-14 d) and a stable period (14-80 d) according to the change of bacterial community diversity. At the species level, 12 dominant bacteria (the relative abundance≥1.00%) were identified, among which, Acetilactobacillus jinshanensis exhibited a relative abundance exceeding 90% from 14 d after brewing. There was a certain correlation between microorganisms and volatile flavor substances in Baijiu brewing process, among them, the number of substances related to the unnamed Ralstonia sp., Thiothrix eikelboomii was more, and 2,4-di-tert-butylphenol and ethyl valerate were significantly correlated with almost all dominant bacterial species (P<0.05). Furthermore, the results of functional prediction showed that the relative abundance of glycine biosynthesis and metabolism, lipid metabolism and nucleotide metabolism in the metabolic pathways related to Baijiu brewing increased during fermentation process, but the relative abundance of amino acid metabolism, biosynthesis of other secondary metabolites, cofactors and vitamin metabolism decreased.

Keywords

• fermented grains|strong-flavor <i>baijiu</i>|high throughput sequencing|community structure|metabolic characteristic