酱香大曲微生物数量和细菌多样性在不同制曲条件下的差异

基于微生物培养技术和高通量测序技术研究了制曲原料和制曲方式对酱香大曲微生物数量、细菌群落结构及其功能基因的影响。研究结果表明：制曲原料相较于制曲方式对微生物数量的影响更大，有机小麦和人工踩曲均有利于细菌和霉菌的生长繁殖；实验选取的酱香大曲优势细菌门包括厚壁菌门（Firmicutes）、变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、norank_Bacteria，优势细菌属包括Kroppenstedtia、芽孢杆菌属（Bacillus）、不动杆菌属（Acinetobacter）、支芽孢杆菌属（Virgibacillus）和高温放线菌属（Thermoactinomyces）等16个属；在细菌群落调节机制和中心（Hub）微生物方面，不同制曲条件下生产的酱香大曲有所差异；就细菌群落多样性和丰度而言，机械有机大曲和人工普通大曲略优于机械普通大曲，但机械普通大曲与机械有机大曲较为相似，与人工普通大曲极为相似；PICRUSt功能基因预测结果表明，机械曲和人工曲、普通小麦曲和有机小麦曲在细菌群落功能基因上均存在不同程度的相似性，但机械曲与人工曲之间更为接近。该研究对比了不同制曲原料和制曲方式条件下酱香大曲的微生物数量、细菌群落结构和细菌功能基因，对于改善提高贵州酱香型白酒品质具有一定的指导意义。

Differences in Microbial Count and Bacterial Diversity in Jiangxiang Daqu under Various Koji-making Conditions

Based on microbial culture and high-throughput sequencing, the effects of different koji-making raw materials and methods on microbial count, bacterial community structure, and functional genes in Jiangxiang Daqu were studied. Koji-making raw materials showed a greater impact on microbial count than koji-making methods, and both organic wheat and artificial koji were conducive to the growth and reproduction of bacteria and fungi. The dominant bacterial phyla in Jiangxiang Daqu were Firmicutes, Proteobacteria, Actinobacteria, and norank_Bacteria, whereas the dominant bacterial genera (n=16) included Kroppenstedtia, Bacillus, Acinetobacter, Virgibacillus, and Thermoactinomyces. The regulatory mechanisms of and hub microbes in bacterial communities in Maotai-flavored Daqu produced under different koji-making conditions were different. In terms of bacterial community diversity and abundance, mechanical organic Daqu and artificial common Daqu were slightly better than mechanical ordinary Daqu, although mechanical ordinary Daqu was slightly similar to mechanical organic Daqu and extremely similar to artificial ordinary Daqu. PICRUSt functional gene prediction revealed different degrees of similarity in the functional genes of bacterial communities between mechanical and artificial koji as well as between common and organic wheat koji, although mechanical and artificial koji were more similar. This study compared the microbial count, bacterial community structure, and bacterial functional genes in Jiangxiang Daqu prepared with different koji-making materials and methods, which has certain guiding significance for improving the quality of Jiangxiang baijiu.