大曲中耐热细菌菌群富含多种酶系，对白酒风味物质的产生有重要的影响。该研究采用高温富集方法从大曲中分离目的耐热细菌菌群，制作成麸曲并应用在小曲白酒酿造过程中，初步探究了三种高温条件下大曲耐热细菌菌群在小曲酒中的功能。通过16S rDNA测序技术分析了微生物结构及多样性，并考察了含水量对麸曲中的细菌生物量的影响，结果发现，大曲中以Bacillus为主的耐热细菌菌群被成功复刻至麸曲中，并占主导地位；在一定范围内随着富集温度的升高，耐热细菌占比越大；水分含量在55%时，麸曲中细菌生物量最高可达8.52×1010 CFU/g。通过小曲酒酿造试验发现，酿造出的最优小曲酒相较于对照组，出酒率提高3.7%，高级醇含量降低27.27%，酯含量增加23.07%，说明在小曲酒酿造过程中使用大曲耐热细菌菌群，可以提高小曲白酒质量。

The thermotolerant bacterial flora in Daqu contains various enzyme systems, which considerably influence the production of flavor substances in liquor. The high-temperature enrichment method was used to isolate the target thermotolerant bacterial flora from Daqu, which was subsequently incorporated into bran koji and utilized in the brewing process of Xiaoqu liquor. The functions of the Daqu thermotolerant bacterial flora in Xiaoqu liquor under three high temperature conditions were preliminarily explored. Microbial structure and diversity were analyzed using 16S rDNA sequencing, and the effect of moisture content on bacterial biomass in bran koji was investigated. The results showed that the thermotolerant bacterial flora, dominated by Bacillus, present in Daqu was successfully transferred in bran koji and became dominant. The increase in enrichment temperature within a certain range also led to an increase in the proportion of thermotolerant bacteria. When the moisture content was 55%, the bacterial biomass in bran koji was up to 8.52×1010 CFU/g. Brewing experiments using Xiaoqu liquor revealed that the optimal Xiaoqu liquor produced by brewing led to an increase in the liquor yield by 3.7%, a decrease in the content of higher alcohol by 27.27%, and an increase in the ester content by 23.07%, compared with the control group.

四川轻化工大学泸州老窖研究生创新基金（LJCX2022-3）；四川省科技创新创业苗子工程项目（23MZGC0042）；酿酒生物技术及应用四川省重点实验室开放基金项目（NJ2022-07）