Evaluation of antimicrobial effect of bacteriocin produced by Lactobacillus acidophilus utilizing molasses and corn steep liquor

Bacteriocins are antimicrobial peptides produced by lactic acid bacteria (LAB) which have emerged as safe biopreservatives in the food industry. However, the conventional commercial medium used to promote bacteriocin production is often costly and impractical for industrial-scale production. This study aimed to explore the utilization of industrial by-products, specifically molasses and corn steep liquor (CSL), in fermentation medium for producing bacteriocin from Lactobacillus acidophilus. The produced bacteriocin was subsequently formulated into antimicrobial powder, and their inhibitory effects on two common foodborne pathogens, Escherichia coli O157 and Salmonella sp. S251, were examined. Among the various medium compositions tested, the highest percentage of inhibition against E. coli 0157 and Salmonella sp. S251 were achieved in the medium containing 10% (v/v) of molasses and 4% (v/v) of CSL. In the formulation of bacteriocin powder, the addition of 60% (w/v) of starch, combined with silicon dioxide, resulted in the shortest drying time. Moreover, the bacteriocin powder produced from 4-fold concentrated bacteriocin at a concentration of 10% (w/v) led to the highest antimicrobial activity against both pathogenic bacteria. Therefore, the efficient production of bacteriocin with remarkable inhibitory effects on foodborne pathogens from L. acidophilus is feasible by utilizing nutrient-rich and cost-effective molasses and CSL.