Optimization of bacteriocin production by Lactobacillus plantarum using Response Surface Methodology

Bacteriocin production is influenced by various factors such as carbon and nitrogen sources as well as fermentation conditions including pH, temperature, and agitation-these factors aid in optimizing bacteriocin production and improving its inhibitory activity against pathogens for great economic significance. The study investigates the effect of growth conditions on bacteriocin production by Lactobacillus plantarum. The response surface methodology was applied to optimize and determine the interaction among the process variables in bacteriocin production by Lactobacillus plantarum and determine their optimum levels. Chloroform-Methanol (2:1 v/v) was used for crude bacteriocin extraction through the liquid-liquid extraction method, and its antimicrobial activity was assessed. The sample has shown inhibitory activity against all the organism,s i.e., E. coli, S. aureus, K. pneumoniae and P. aeruginosa good diffusion. Compared to control and ciprofloxacin, the sample at all concentrations (Lab 9, 1%, 2%, 3%) has shown better inhibitory activity in pH-7 and-8 at 37 °C against S.aureus in good diffusion. The selected factors were carbon and nitrogen source, temperature, and pH. The bacteriocin was produced at maximum activity in MRS broth supplemented with 1% dextrose and 1% ammonium nitrate. RSM analysis found that the optimal temperature for bacteriocin production was 36°C at a pH of 6.5 using 1% inoculum. At the same time, the increase in the percentage of inoculum (2% and 3%) did not affect bacteriocin production. The quadratic model found that temperature and pH profoundly affected bacteriocin production.