Optimization of Growth Conditions for Enhanced Bacteriocin Production from Lactobacillus brevis UN by One Variable at a Time (OVAT) and Response Surface Methodology (RSM)

Lactic acid bacteria have recently caught the attention of scientific researchers. These food associated organisms and transient inhabitant of human gut has potential to curb down the growth of spoilage and disease causing microbes due to its ability to produce bacteriocin, lactic acid, acetic acid, hydrogen peroxide etc. Bacteriocins are biologically derived primary or modified product of bacterial ribosomal synthesis, which have an antibacterial activity. Bacteriocin producing isolates were isolated from traditional and least explored food samples of Himachal Pradesh and North East India by standard microbiological techniques. Isolated strains screened for their bacteriocin production. Growth conditions for bacteriocin production have been optimized by statistical tools viz. One variable at a time method and Response Surface Methodology (RSM). In the present study bacteriocin producing isolate UN was identified and selected for further studies. Various growth conditions viz. growth cycle, effect of incubation temperature, pH, inoculum size were studied to monitor their effect on bacteriocin production. Bacteriocin production was optimized through Classical One Variable at a Time Method (OVAT) and Response Surface Methodology (RSM). Bacteriocin production was maximum at early stationary phase i.e. 34^th h, at pH range 4.0-6.5, at temperature 30-35°C with an inoculums size 1.0, 1.5, 2.0 OD at 10 %. The production of bacteriocin seems not to be inducible. The incubation conditions andperfect combination of these conditions particularly temperature, pH, inoculum size and time strongly influence the effective yield of active bacteriocin. One Variable at a Time Method and Response Surface Methodology proved to be powerful tools in optimization of bacteriocin production by Lactobacillus brevis UN.