Functional Properties of Heavy Metal Tolerant Probiotic Strains Isolated from Curd

ABSTRACT

The two heavy metal tolerant bacterial isolates L. fermentum SN_4 and L. rhamnosus SN_6 were identified (isolated from curd samples) which were found to be potentially resistant to Cr6+, Pb2+ and Cd2+ under study. Both the isolates were resistant to simulated gastric juices at pH 2.0 and 3.0 at 0 hours and survived well more than 50% in 0.2%, 0.3%, 0.5% and 1.0% bile salt solution but the isolate L. rhamnosus SN_6 showed the best survival at all the concentrations of bile salt. These two isolates showed poor antagonistic agent activity against the four pathogenic bacteria viz. E. coli, B. cereus, S. typhimurium and V. cholera. L. fermentum SN_4 showed resistant to all antibiotic except clindamycin and azithromycin, on the other hand, L. rhamnosus SN_6 was found resistant to clindamycin and tetracycline only. Also, they were found to be haemolytic negative which proved them to be a potential probiotic.