Screening and Isolation of Functional Lactic Acid Bacterial Strains from Traditional Fermented Vegetables Juice (Jiangshui), Northwest China

Aims: Jiangshui (JS) is a traditionally fermented vegetable juice which is unique to northwest China as a seasonal beverage, especially during summer season. This study was designed to isolate functional lactic acid bacteria (LAB) from JS to investigate their probiotic properties as well as high cholesterol lowering capacity in human serum.

Design of Study: Lanzhou jiaotong university, Department of chemical and biological engineering, Laboratory of microbiology and food biotechnology, Lanzhou city, Gansu, between March and January 2018.

Methodology: The strains were initially screened by MRS culture medium and high cholesterol culture medium. Then, strains were confirmed by microbiological, biochemical analysis as well as 16S recombinant DNA sequencing.

Results: After investigating different parameters of isolated LAB strains such as bile tolerance, acid resistance and antimicrobial drug sensitivity, each strain have the capacity of cholesterol degradation. The results showed that the four strains with cholesterol reduction rate (75%) were mostly identified as Lactococcus lactis ssp. lactis (M2- JQ953697.1), two of them were Brevibacterium casei (M5 and H4- JF951998.2) and one was Lactococcus raffinolactis (Q7- KC951926.1.

Conclusion: In conclusion, JS is one of the best source for its nutritional values and its potential for cholesterol lowering capacity in human serum, especially M2 and Q7 strains have strong ability to survive at lower acidic conditions of gastric juices and tolerate the bile salts.