Relationship between microbial protein and amino acid metabolism in fermented grains of long fermentation period strong-flavor Baijiu

Abstract

The long fermentation period constitutes a crucial process for enhancing the quality of base liquor in the production of Chinese strong-flavor Baijiu. In the present study, a comprehensive metaproteomic analysis of fermented grains in the long fermentation period led to the identification of 44 plant proteins and 1460 microbial proteins. Following 12 days of fermentation, bacterial proteins exhibited a rapid surge, constituting the predominant components of fermented grains proteins, ranging from 64.64 to 81.28%. The differential proteins were predominantly associated with carbohydrate metabolism, energy metabolism, and amino acid metabolism. Among these, days 18 to 220 were dominated by differential protein in the protein hydrolase system and amino acid metabolic of the bacteria. Pathway analysis delineated the potential metabolic pathways through which cysteine, tyrosine, proline, isoleucine, among others, could be metabolized to yield pyruvic acid, acetyl-CoA, ultimately leading to the production of acetic acid, butyric acid, and hexanoic acid. Furthermore, phenylalanine underwent metabolism, resulting in the production of phenylacetaldehyde, phenylacetic acid, and phenylacetic acid ethyl ester. With the extension of fermentation time, lactic acid underwent conversion to pyruvic acid, contributing to the generation of other acids, while aldehydes were converted to alcohols and acids.

Funding

the National Natural Science Foundation of China,(22138004)