Abstract

ISOLATION, IDENTIFICATION AND CHARACTERISATION OF A NOVEL PROBIOTIC STRAIN (LACTOBACILLUS PARACASEI KUMBB005) FROM COW MILK SAMPLES AND ITS ANTIBACTERIAL ACTIVITY

V.Usha Rani and B.V. Pradeep*

Abstract

Lactobacillus sp., was isolated from 10 raw cow milk samples using MRS agar, out of 15 isolates 4 Lactobacillus isolates (KUMBB001, KUMBB002, KUMBB003, KUMBB005) were selected for characterization study. The isolates were examined for their probiotic properties such as pH resistance, NaCl tolerance, bile salt tolerance, antibacterial activity and antibiotic susceptibility. Among the 4 isolates KUMBB005 showed resistance to acidic pH 6, maintained good growth at NaCl concentration (1-9%) and the isolates depicted good tolerance against (1-5%) bile salt (Ox-gall). Based on the biochemical characterization the isolates KUMBB005 has shown potent growth and antibacterial activity which was further subjected to 16S rRNA sequencing. The sequence was submitted in NCBI with accession number KM008572. After sequencing and phylogenetic analysis the isolate KUMBB005 was identified as Lactobacillus parcasei. The cell free extract of the isolate exhibited good antibacterial activity against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Klebsiella pneumoniae MTCC 4030, Pseudomonas aeruginosa ATCC 27853 and Salmonella typhi MTCC 734. Lactobacillus paracasei KUMBB005 also exhibited good resistance towards various antibiotics such as Kanamycin, Erythromycin, Vancomycin and Streptomycin. Lactobacillus paracasei KUMBB005 obtained from milk sample were more effective than other isolates and could be assigned as potential strain for further research work towards its probiotic application.

Keywords: Lactobacillus sp., Characterization, 16S rRNA sequencing, Lactobacillus paracasei, Antibacterial activity.