Effect of lactic acid bacteria on the structure and potential function of the microbial community of Nongxiangxing Daqu

Abstract

OBJECTIVES:The microbial community structure of the saccharifying starter, Nongxiangxing Daqu Daqu , is a crucial factor that determines the quality of Baijiu. lactic acid bacteria (LAB), the dominant microorganisms in the Daqu. The present study investigated the effects of LAB on the microbial community structure and its contribution to microbial community function during the fermentation of Daqu.RESULTS: Box-line variance analysis shows that LAB showed a signi cant stage-speci c succession pattern during Daqu fermentation. The LEfSe analysis and the random forest learning algorithm identi ed LAB as vital differential microorganisms during Daqu fermentation. The correlation co-occurrence network constructed based on Spearman's rank correlation coe cients showed aggregation of LAB and Daqumicroorganisms, indicating LAB's signi cant position in in uencing the microbial community structure. LAB showed negative correlations with Bacillus, Saccharopolyspora, and Thermoactinomycesbut positive correlations with Issatchenkia, Candida, Acetobacter, and Gluconobacter. The predicted genes of LAB enriched 20 functional pathways during Daqu fermentation, including Biosynthesis of amino acids, Alanine, aspartate and glutamate metabolism, Valine, leucine and isoleucine biosynthesis and Starch and sucrose metabolism, which suggested that LAB had the functions of polysaccharide metabolism and amino acid biosynthesis.CONCLUSION: Thus, the study indicates that LAB is important in determining the composition and function of Daqu microorganisms and also suggests that LAB are closely related to the production of nitrogenous avor substances in Daqu. The study provides a foundation for further exploring the function of LAB and the regulation of Daqu quality.

The response pattern of the microbial community structure and metabolic profile of jiupei to Bacillus subtilis JP1 addition during baijiu fermentation

“…In a ‘multi‐microorganism fermentation of solid‐state’ brewing system, key microorganisms exert significant influence on both the community composition and functionality 4‐6 . For example, interactions involving functional strains such as Bacillus , Lactobacillus and Aspergillus enhance the abundance of metabolic enzyme genes in the daqu microbial community, 7 facilitate the activities of functional enzymes such as amylase and protease in jiupei 8 and effectively increase ethanol content in liquor 9 .…”