Bacteriocins from lactic acid bacteria (LAB) are useful to control the persistent development of pathogenic microorganisms in food and medicine fields. The bacteriocin acidocin was extracted from Lactobacillus acidophilus M1 that was isolated from fermented milk, purified using ammonium sulphate fractionation, and gel filtration column chromatography using Sephadex matrix and applied as a potential antibacterial agent. The molecular weight of the purified acidocin was estimated using SDS-PAGE to be 6.6 kDa. The acidocin was compared with silver nanoparticles (SNPs), biosynthesized by Aspergillus brasiliensis (niger) ATCC 16404, against two bacterial strains Bacillus cereus ATCC 14579 and Staphylococcus aureus ATCC 25923. Both acidocin and SNPs showed significance antibacterial effects using disc and well diffusion methods; the maximum antibacterial activity was proved against B. cereus from acidocin/SNPs composite using a ratio of 1/1 from each agent. The application of acidocin/SNPs composite as immersion solution, for disinfecting chicken eggshells, resulted in remarkable reduction in microbial load on the shells of 5.53 log10 CFU/eggshell. Results could provide an eco-friendly approach for potential antimicrobial composites to be used in food preservation and other health protection researches.
Keywords: Aspergillus brasiliensis; Lactobacillus acidophilus; bacteriocins; food preservation; purification.
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