Abstract: In order to investigate the diversity of lactic acid bacteria in fermented rice noodles at different fermentation times, the diversity and functional predication of lactic acid bacteria on days 0, 1, 2, 3 and 4 of fermentation were studied by high-throughput sequencing. The results showed that a total of 278 operational taxonomic units (OTU) belonging to 27 genera in 5 phyla were identified in 15 samples of fermented rice noodles. During the entire fermentation process, Lactobacillus was absolutely dominant, and its relative abundance was over 99%. The diversity of lactic acid bacteria decreased with prolonged fermentation time. There were 32 species detected at 0 day, while only 12 species at 4 days at the species level. In addition to Lactobacillus, Lactococcus and Leuconostoc were also present. PICRUSt gene function prediction showed that the predicted functional genes at different fermentation periods were mainly those involved in amino acid transport and metabolism, carbohydrate transport and metabolism, lipid transport and metabolism, coenzyme transport and metabolism, energy production and conversion, and other metabolism-related genes. This study provides a theoretical rationale for further studying the mechanism of the effect of lactic acid bacteria on the eating quality of fermented rice noodles and for the development of fermentation starters for rice noodle.

Key words: fermented liquid of rice noodles; high-throughput sequencing; lactic acid bacterial diversity; function prediction