Correlation analysis between microbial communities and physicochemical indicators during low-salt solid-state fermentation of soy sauce in Deyang

In this study, the physiochemical indicators of fermented grains during low-salt solid-state fermentation of Deyang soy sauce were analyzed, the microbial community composition and succession laws during the fermentation process were analyzed by high-throughput sequencing technology, and the physiochemical indicators and microbial genera were analyzed by Spearman correlation. The results indicated that the dominant bacterial genera of fermented grains during low-salt solid-state fermentation process of Deyang soy sauce were Bacillus (41.2%), Unclassified Enterobacteriaceae (19.5%), Klebsiella (13.6%), Enterobacter (12.4%), and Enterococcus (3.4%). The dominant fungal genera was Aspergillus (99.3%). As fermentation progressed, the relative abundances of Bacillus (34.4%-46.7%) and Enterococcus (1.0%-4.1%) significantly increased (P<0.05), while the relative abundances of Unclassified Enterobacteriaceae (21.9%-17.8%) and Klebsiella (23.6%-8.8%) significantly decreased (P<0.05). The correlation analysis results showed that Cronobacter, Aerococcus, Staphylococcus, Enterococcus, Bacillus and Enterobacter were positively correlated with reducing sugars, neutral protease, and amino acid nitrogen. Aspergillus was positively correlated with neutral protease, alkaline protease, and total acid, while it was negatively correlated with amino acid nitrogen and reducing sugars.