Abstract: This study was undertaken to analyze the microbial communities in Pixian soybean paste during the postfermentation process by high-throughput sequencing method. The results revealed that at the taxonomic levels of microbes including phylum, class, order, family, and genus, high-throughput sequencing could detect a total of 57 phyla, 174 classes, 321 orders, 535 families and 921 genera. Post-fermentation time had a significant effect on the bacterial community composition of Pixian soybean paste. During post-fermentation, the quantities of Enterobacteriaceae and Streptophyta continued to decrease whereas Sphingomonadaceae, Bacillaceae, Clostridiaceae and Peptostreptococcaceae increased first and then decreased, most of which reached their peak values during 1 to 3 years. However, after 6 years of fermentation, the bacterial community of Pixian soybean paste was significantly lower than that of other samples. With this method, a large number of non-cultureable bacteria and unclassified bacteria were detected. The results of bacterial diversity analysis were close to the microecology of the samples, which were helpful to better understand the bacterial diversity of Pixian soybean paste and might provide a scientific support for the modernization of the traditional industry and the control of food quality and safety.

Key words: Pixian soybean paste, bacterial community, high-throughput sequencing