Utilization of RSM for optimization of physical variables to improve bacteriocin production from Lactobacillus plantarum strain MS

The utilization of natural antimicrobial substances has been increased in the pharmaceutical sector due to their stability and inhibition activity against pathogenic microorganisms. In the current study, the bacteriocin synthesis by locally isolated Lactobacillus plantarum MS from yogurt, has been optimized by using response surface methodology. Statistical optimization of physical variables by using Box-Behnken design, 3200 AU/mL bacteriocin activity was detected at 30 C temperature, 18h incubation time, and pH 6 against Staphylococcus aureus. The resulting bacteriocin was found to be stable a broad range of pH (2-12) and temperature (37-100 C) but the activity of bacteriocin was slightly disturbed at 121 C. Besides, bacteriocin showed stability after treatment with various enzymes (catalase, amylase, and lipase), salt (NaCl), and surfactants (triton X-100, EDTA, and SDS) but found sensitive by treating with proteolytic enzymes (proteinase K and trypsin) in comparison with untreated bacteriocin. Because of such biochemical characteristics, these antibacterial peptides could be possibly incorporated in the field of pharmacy to fulfil consumers' demand for natural remedies. Keywords: Lactic acid bacteria, bacteriocin, antibacterial activity, response surface methodology, Box-Behnken design.