Diversity and dynamics of bacteria in Pixian broad-bean paste

Abstract:

[Objective] The dynamic changes of bacteria in the fermentation process of Pixian broad-bean paste were explored from the species, abundance, and number of bacteria. [Methods] The 16S rRNA gene sequencing was carried out to analyze the bacterial species and abundance at four fermentation stages of Pixian broad-bean paste, and qPCR was employed to determine the total number of bacteria at different fermentation stages. [Results] The bacteria in Pixian broad-bean paste showed a dynamically stable community at the initial fermentation process, high richness during the whole fermentation period, and increased diversity over fermentation time (Shannon index increased from 1.25 to 3.50). The number and diversity of bacteria were associated with the fermentation environment at the early fermentation stage, and the bacterial diversity varied at different fermentation stages. Pantoea was the dominant genus during the fermentation of dry pepper, accounting for 20%. During the fermentation of broad bean, Staphylococcus had the highest relative abundance, which reached 38%. The dominant genus was Lactobacillus at the fermentation stages of red oil broad bean and Pixian broad-bean paste, with the relative abundance of 27% and 62%, respectively. [Conclusion] The relatively abundant bacteria at the early fermentation stage might have a significant impact on the quality and yield of Pixian broad-bean paste.