Effects of biofortification on microbiota dynamics and flavor metabolism in light-flavor Baijiu fermentation process

Daqu, as an important starter and special raw material for Baijiu fermentation, is one of the main factors affecting Baijiu fermentation. Utilizing Daqu fortified with functional strains had an impact on the metabolic activity of microbial community as well as the flavors of the Baijiu that were generated. This work aimed to reveal the function of aroma-producing yeast strain Wickerhamomyces anomalus YW1604 and YW3503 in light-flavor Baijiu, the microbial community structure was investigated, and the results revealed that Pediococcus, Weissella, Wickerhamomyces, Aspergillus, and Saccharomycopsis were the predominant genera. A total of 41 flavor compounds including esters (15), acids (6), alcohols (7) and other compounds (13) were detected in samples during the different stages of fermentation. Among them, the content of ethyl acetate, ethyl butyrate, ethyl lactate, ethyl palmitate, ethanol, and phenylethyl alcohol increased. The results indicate that the fungal community structure in the experimental groups was altered after the addition of W. anomalus, higher contents of aroma compounds and ethyl acetate were mainly correlated with Pediococcus and Wickerhamomyces. This work may provide an effective microbial regulation strategy for Baijiu fermentation, and also provides basic data for the utilization of functional strains to biofortify the Baijiu fermentation process to achieve quality improvement.

大曲（Daqu）作为白酒（Baijiu）发酵的重要发酵剂与特殊原料，是影响白酒发酵的核心因素之一。采用经功能菌株强化的大曲，会对微生物群落的代谢活性以及成品白酒的风味产生影响。本研究旨在揭示产香酵母菌异常威克汉姆酵母（Wickerhamomyces anomalus）YW1604与YW3503在清香型白酒（light-flavor Baijiu）发酵中的作用，通过解析微生物群落结构，结果显示片球菌属（Pediococcus）、魏斯氏菌属（Weissella）、威克汉姆酵母属（Wickerhamomyces）、曲霉属（Aspergillus）以及类酵母属（Saccharomycopsis）为优势菌群。在发酵不同阶段的样品中，共检测到41种风味物质，涵盖酯类15种、酸类6种、醇类7种及其他类别物质13种。其中，乙酸乙酯、丁酸乙酯、乳酸乙酯、棕榈酸乙酯、乙醇及苯乙醇的含量显著提升。结果表明，添加异常威克汉姆酵母后，实验组的真菌群落结构发生改变；风味物质总含量及乙酸乙酯的高含量主要与片球菌属和威克汉姆酵母属呈显著相关。本研究可为白酒发酵提供一套高效的微生物调控策略，同时也为利用功能菌株生物强化白酒发酵工艺以实现品质提升提供基础数据支撑。