Purification and Characterization of Broad-Spectrum Bacteriocin (Fermencin) Produced by Lactobacillus fermentum 28D1
Keywords:
Bacteriocin, Fermencin, Lactobacillus fermentum, ammonium sulfate precipitation, ion exchange chromatography, SDS-PAGE, thermostability, antimicrobial peptideAbstract
Bacteriocins synthesized by lactic acid bacteria (LAB) have increasingly drawn global attention due to their antimicrobial potential, biodegradability, and suitability for food and pharmaceutical applications. This study examines the production kinetics, stability profile, physicochemical characterisation, and purification approach of a broad-spectrum bacteriocin fermencin secreted by Lactobacillus fermentum 28D1. Ammonium sulfate precipitation (60-80%) was applied to crude bacteriocin derived from cell-free supernatant, resulting in a 16.4-fold increase in specific activity. Anion exchange chromatography was used for additional purification, which produced a 69.26-fold purification with a 128% total recovery. Fermencin's molecular weight was calculated by SDS-PAGE analysis to be roughly 8.5 kDa. Enzyme susceptibility studies revealed complete inhibition by proteolytic enzymes, confirming its proteinaceous nature, whereas lipase and catalase exhibited negligible impact. Thermal stability assays demonstrated activity retention from 60°C to 100°C, followed by a decline above autoclaving temperature. PH tolerance was maximal between 4–7 but appreciable activity persisted from pH 2–8. Production kinetics indicated that optimal bacteriocin yield occurred at 35°C and pH 6.5 after 24 h of incubation. The findings demonstrate that fermencin is a thermostable, moderately acid-tolerant peptide with industrial relevance in food preservation, probiotics, and therapeutic applications. This research contributes significantly to bacteriocin biotechnology, specifically highlighting purification efficiency, stability, and optimal fermentation parameters necessary for scale-up and commercialization.
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