Abstract

EVALUATION OF CYTOTOXICITY AND CHARACTERIZATION OF BACTERIOCINS OF POTENTIAL PROBIOTIC ISOLATES FROM CATTLE FARM SOIL OF DIBRUGARH DISTRICT, ASSAM, INDIA

Nuredin Mohamedkassm Siraj* and R.N.S. Yadav

Abstract

Antimicrobial property and safety are important features in the screening of probiotic isolates. The study aims to evaluate the safety and characterize the antimicrobial activity of crude bacteriocins of newly isolated potential probiotic bacterial strains namely E. faecium DUD3, Bacillus sp DUA4 and Enterobacter sp DUE2 from cattle farm soil in Dibrugarh District, Assam, India. Cytotoxicity test of the crude bacteriocin of the isolates against HEK293 and HT29 cell lines was evaluated using MTT assay and the result showed survival rate of more than 50% for both the cell types following treatment with bacteriocin of E. faecium DUD3. However, the survival rate of these cell types was found be less than 50% following treatment with Bacillus sp DUA4 and Enterobacter sp DUE2. Characterization of the crude bacteriocin of the isolates was studied using assay of the residual antimicrobial activity following treatment with proteolytic enzymes and at different temperature and pH. The crude bacteriocin of E. faecium DUD3 was found to be sensitive to all proteolytic enzymes tested and showed significant resistance to a wide range of pH and temperature. In the present study, out of the three isolates, E. faecium DUD3 was found to be most potential probiotic candidate followed by Bacillus sp DUA4.

Keywords: Cytotoxicity, MTT, Bacteriocin, E. faecium, Bacillus spp.