Physiological and genomic characterization of an exopolysaccharide- producing Weissella cibaria CH2 from cheese of the western Himalayas

摘要

Weissella cibaria CH2 is an exopolysaccharide (EPS) producing bacterium, isolated from cheese. Maximum EPS production (81.3%) was observed with sucrose at 20 degrees C. The CH2 strain was tolerant of simulated gastric juice (pH 3) with a 5.3% decrease in the viable count after 180 min, but not of pH 2. Similarly, no significant decrease in the viable count was observed in the presence of simulated intestinal juices (pH 8) and bile salts (0.3%) after 240 min. The CH2 strain showed good aggregation ability and antimicrobial activity against representative pathogenic bacteria that may promote the colonization of the CH2 strain in the gastrointestinal tract. Complete genome sequencing supplemented the experimental evidence as genes encoding for EPS production, gastrointestinal tolerance, and adhesion were observed in the CH2 genome. Genomic analysis also showed the presence of functional traits such as cholesterol reduction, beta-galactosidase production, vitamin, and essential amino acid biosynthesis. The absence of transferable antibiotic resistance genes and virulence factors in the CH2 strain was further confirmed using genome sequencing. The present study highlights the potential of the CH2 strain for use as a probiotic.