Screening and genome analysis of potential probiotic lactic acid bacteria with broad-spectrum antibacterial activity from Sichuan sun-dried vinegar grains (Cupei)

Abstract

This study aimed to isolate lactic acid bacteria (LAB) with broad-spectrum antibacterial activity and potential probiotic properties from the Sichuan sun-dried vinegar grains (Cupei), a traditional Chinese bran fermented vinegar. A total of 115 LAB strains were isolated from the Cupei, among which 33 inhibited both Gram-negative and Gram-positive indicator bacteria. Subsequently, 27 strains devoid of hemolytic and coagulase enzyme activity were selected for further evaluation of their probiotic properties and Lactobacillus plantarum SC27 was revealed as a potential probiotic strain, as it demonstrated notable gastrointestinal tolerance, hydrophobicity, auto-aggregation ability, and multiple antibiotic sensitivity, and particularly noteworthy for broad-spectrum antibacterial activity. Whole genome sequencing further unveiled that SC27 harbored bacteriocin gene clusters likely responsible for bacteriocin production, as well as an extensive variety of phosphotransferase system transporters facilitating its adaptability to diverse food substrates. In addition, based on the analysis of genes involved in antibiotic resistance, virulence factor, we speculated that SC27 is safe for application in food industry. Furthermore, the genomic analysis revealed several stress-response and adhesion-related genes, known to confer beneficial properties to probiotic bacteria. In conclusion, our comprehensive genomic and phenotypic analyses confirm the potential of SC27, with broad-spectrum antibacterial activity, as a probiotic used in food.