Brewing-related genes annotation of Bacillus velezensis CS1.10S isolated from traditional moromi and its effects on promoting soy sauce fermentation

Abstract

The abundance of salt-tolerant microorganisms in moromi contributes greatly to the flavor of soy sauce, and Bacillus velezensis CS1.10S, isolated from the traditional Chinese sun-brewed moromi, is one of them. In order to understand the intrinsic mechanism of the fermentation properties of this bacterium, 4211 genes obtained from the sequencing of its genome were annotated, and it was found that genes encoding carbohydrate metabolism and transport accounted for 7.43%. Genes encoding amino acid metabolism and transport accounted for 9.66%, with a total of 284 genes related to amino acid synthesis, and 13 metabolic pathways covering 19 amino acids, which showed that CS1.10S had good carbon and nitrogen metabolism and amino acid production ability. KEGG also annotated three kinds of salt tolerance-related genes, which explained the good performance of CS1.10S in tolerating salt up to 160 g/L. A comparative study of the quality indexes of fermented soy sauce supplemented with CS1.10S revealed that the amino acid nitrogen content of soy sauce supplemented with CS1.10S on the 10th day of fermentation was 7.51% higher than that of the control group, and its total free amino acid content also increased by 42.38%. The contents of reducing sugars and volatile flavor compounds also increased, but the total acid did not change much, indicating that CS1.10S was beneficial to the taste and aroma of soy sauce. The annotation of CS1.10S with brewing-related genes and the corresponding evidence from fermentation tests indicated that CS1.10S has the potential to improve the flavor of soy sauce.