Abstract:In order to study the composition of caproic acid-producing bacterial community in Medium/high-temperature Daqu, four different medium/high-temperature Daqu in Sichuan were used as the research objects. After the enrichment with the enrichment medium, the metagenomic DNA of Daqu and Daqu enrichment liquid samples were subjected to high-throughput sequencing with 16S rRNA gene amplicons, and the composition of caproic acid-producing bacterial community in Daqu was analyzed. The results showed that the diversity and abundance of the potential caproic acid-producing bacterial community in Daqu increased after the enrichment. The potential dominant caproic acid-producing bacteria (relative abundance >1%) in Daqu included Clostridium_sensu_stricto_18 (2.19%~69.00%), Clostridium_sensu_stricto_15 (1.76%~7.65%) and a small amount of Clostridium_sensu_stricto_12, Clostridium_sensu_stricto_1, Clostridium_sensu_stricto_10, Clostridium_sensu_stricto_7 and Caproiciproducens. Among them, in terms of the main potential caproic acid-producing bacterial community, Q1 Daqu was dominant with Clostridium_sensu_stricto_18, and Clostridium_sensu_stricto_15; Q2 Daqu was dominant with Clostridium_sensu_stricto_1, Caproiciproducens, and Clostridium_sensu_stricto_18; Q3 Daqu was dominant with Clostridium_sensu_stricto_18, and Caproiciproducens; Q4 Daqu was dominant with Clostridium_sensu_stricto_18, and Clostridium_sensu_stricto_1. The results showed that there were differences in the composition of caproic acid-producing bacterial communities in different medium/high-temperature Daqu in Sichuan. The preliminary analysis was carried out to provide a theoretical basis for the directional study of caproic acid-producing bacteria in Daqu, and also provide a direction for the preparation of high-quality Daqu to promote the quality improvement of Nongxiangxing liquor.