Abstract: In this study, the diversity and dynamic changes of?the bacterial community during the natural fermentation of soybean paste, a traditional fermented food popular in northeast China, were analyzedusing polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technology and high-throughput sequencing. Results showed that bacterial operational taxonomy unit (OTU) values were fluctuant during the fermentation and reached a maximum on day 21, indicating the largest bacterial population. Analysis of DGGE profiles and the distribution of bacteria at the genus level suggested that Leuconostoc sp., Enterococcus sp., Tetragenococcus sp. and Lactobacillus sp. were predominant bacterial strains for different fermentation stages of soybean paste. Among these, Tetragenococcus sp. was more fluctuant and and vulnerable to both internal and external environments. Enterococcus faecium, Leuconostoc sp. and Weissella viridescens decreased with fermentation time indicating that these bacteria might be mainly involved in the production of catabolic enzymes in the early fermentation stage and played a role in the adjustment of the internal environment during the whole fermentation process.

Key words: traditional fermented soybean paste in northeast China, PCR-DGGE, sequencing for microbial diversity, dominant bacterial strains, operational taxonomy unit (otu)