Abstract:
Based on the high-throughput DNA sequencing of Illumina, the diversity of microbial community composition in the fermentation broth of the pickled radish during the peak value period (3rd day) and the background value period (7th day) of nitrite concentration was entirely clarified in this study. Total 373 and 349 bacterial operational taxonomic units (OTU) were obtained from the samples on the 3rd and 7th day, which belonged to 135 and 127 bacterial genus, respectively. The Chao1 index, richness index and diversity index of bacterial community in the samples on the 3rd were higher than that on the 7th day. In the samples on the 3rd day, the bacterial phylum Proteobacteria was the most dominant group (72.1%), and Erwinia, Aeromonas, Pseudomonas, Shigella and Delftia were the main genus of 45.0%, 7.4%, 6.6%, 6.0% and 5.1%, respectively. The bacterial phylum Firmicutes was the second dominant group (18.9%), and the genus Lactococcus was the main genus of 10.5%. In the samples on the 7th day, the bacterial phylum Firmicutes was the most dominant group (84.0%), and Leuconostoc, Lactococcus, Weissella and Pediococcus were the main genus of 27.5%, 19.9%, 19.2% and 16.3%, respectively. The relative abundance of the previous dominant phylum Proteobacteria decreased to 10.5%, and the relative abundance of all genuses were below to 2%. The results indicated that the diversity of bacterial community in the fermentation broth of the pickled radish might shift following the change of the nitrite concentration, which was closely related to the formation and degradation of nitrite in the fermentation broth.
