研究接种大曲中优势菌属枯草芽孢杆菌后在混菌发酵下微生物群落改变，分析代谢产物的差异。采用高通量测序技术、HS-SPME-GC-MS、PLS-DA分析接种前后的微生物群落结构和代谢的差异，采用斯皮尔曼（Spearman）相关性分析接种前后微生物与差异风味物质的相关性。研究表明接种枯草芽孢杆菌后微生物的相对丰度有明显的变化，其中变化最大的为Bacillus从76.56%降为0.04%，Enterobacter从0.01%上升为71.53%，Pichia从62.17%降为12.89%，且由LEFSE分析可知接种后群落结构也有明显的变化。产物分析中，接种前后代谢产物有明显差异，己酸乙酯、2,3,5,6-四甲基吡嗪、乙酸乙酯等19种代谢物是显著差异代谢产物，由相关性分析可知，代谢产物的变化与接种后有显著变化的微生物有关，接种枯草芽孢杆菌后会影响微生物的变化，从而使代谢产物产生变化。该研究揭示了接种枯草芽孢杆菌后混菌发酵下群落结构与代谢产物的差异及其两者间的相关性，为探明枯草芽孢杆菌在多菌共菌发酵体系中的作用提供基础数据。

Changes in the microbial community and differences in metabolites following the inoculation of a mixed fermentation system with Bacillus subtilis, the dominant species from Daqu, were investigated herein. High-throughput sequencing, HS-SPME-GC-MS, and PLS-DA were used to analyze the differences in microbial community structure and metabolism before and after inoculation, and Spearman correlation analysis was used to examine the correlation between the microorganisms and different flavor compounds. The results showed significant changes in the relative abundance of microorganisms after inoculation with B. subtilis, with the most significant changes being Bacillus decreasing from 76.56% to 0.04%, Enterobacter increasing from 0.01% to 71.53%, and Pichia decreasing from 62.17% to 12.89%. LEfSe analysis also revealed notable changes in the community structure after inoculation. The analysis of metabolites revealed significant differences before and after inoculation, with 19 metabolites, such as ethyl hexanoate, 2,3,5,6-tetramethylpyrazine, and ethyl acetate, being significantly different. Inoculation of Bacillus subtilis affected microbial changes, leading to variations in metabolites. Correlation analysis revealed that the changes in metabolites were related to the microorganisms with significant changes after inoculation. We found differences in community structure and metabolites in a mixed fermentation system after inoculation with B. subtilis and a correlation between the two, providing fundamental data for understanding the role of B. subtilis in a multispecies co-fermentation system.

四川省科技厅重点研发计划项目（2019YFS0518）；四川轻化工大学研究生创新基金资助项目（Y2020064）