STATISTICAL OPTIMIZATION OF BACTERIOCIN PRODUCTION BY PEDIOCOCCUS ACIDILACTICI IN A SIMPLE FOOD-GRADE MEDIUM

Bacteriocins produced by lactic acid bacteria are attractive as food biopreservatives in place of chemical preservatives. Pediococcus acidilactici was found to produce bacteriocin that can inhibit bacterial and fungal food contaminants. Based on the conventional deMan, Rogosa and Sharpe (MRS) medium, simplified food-grade medium for bacteriocin production by the bacterium was developed containing casein peptone and dextrose for food application and scale-up of the bioprocess. Central composite rotatable design was used to study the main and interactive effects of medium components and fermentation parameters, i.e., temperature and pH on bacteriocin production by Pediococcus acidilactici. The optimized medium conditions with 97% desirability under the set criteria were: casein peptone 3.97%, dextrose 3.45% at pH=7.0 and temperature 35C. Bacteriocin titer obtained from the optimized casein peptone and dextrose medium was comparable with MRS medium (538AU/mL). Practical Applications Bacteriocins from lactic acid bacteria are of potential usefulness as natural substitutes for chemical food preservatives in the production of food with enhanced shelf-life. The bacteriocin obtained from Pediococcus acidilactici has a wide spectrum of activity against bacterial and fungal food pathogens. Usually, bacteriocins is obtained from deMan, Rogosa and Sharpe medium that contains nitrogen sources such as beef extract, yeast extract, proteose peptone and ammonium citrate that is not acceptable by the consumers. Keeping this in mind, we have developed a food-grade medium containing casein peptone and dextrose for food applications. Further casein peptone and dextrose concentrations along with fermentation parameters such as pH and temperature were optimized to give optimum yield of bacteriocins. So, the bacteriocin produced in the food-grade medium should be acceptable by the consumers as well as economical according to industrial point of view.