OPTIMIZATION OF PRODUCTION CONDITIONS FOR BACTERIOCINS OF LACTIC ACID BACTERIAL (LAB) ISOLATESPathade A.G. and Bodhankar M.G.Abstract Bacteriocins are ribosomally synthesized antimicrobial peptides produced by bacteria and are active against other bacteria, either in the same species (Narrow spectrum) or across genera (broad spectrum). The 16 out of 20 LAB isolates showed zones of growth inhibition against one or more of the test pathogens. The two promising isolates were identified as Pediococcus pentosaceus strain âI and Pediococcus pentosaceus strain âII by 16s-rRNA gene sequencing method. These two isolates were subjected to optimization studies. The optimization of medium and other conditions were studied with respect to carbon source, nitrogen source, pH, inoculum size, incubation period and incubation temperature using deMan Rogosa Sharpe (MRS) basal medium, and it was found that, both LAB isolates showed maximum yields of bacteriocins in their respective optimized mediaas compared to basal medium. The medium and other conditions were optimized at 0.1-L flask studies. The optimized conditions include 2% Glucose as carbon source, 1% NH4CL as nitrogen source, pH 6.5 in the MRS base medium, inoculum size of 6 % at 108Colony Forming Units (CFU)/ml of the suspensions, incubation period of 48-h and 30 oC temperature of incubation. These optimized conditions were used in the further work. |