Evaluation of Heat Denaturation and Adsorption-Desorption as a Method for Concentrating Pediocin from Pediococcus acidilactici Fermentation

Abstract

A preliminary antimicrobial assay showed the antimicrobial activity of P. acidilactici but the SDS-PAGE did not reveal pediocin, an antimicrobial peptide produced by Pediococcus strain. The efficient downstream processing of P. acidilactici fermentation is studied to analyze pediocin. This research is conducted to assess the compatibility of different methods in concentrating pediocin in the cell-free supernatant (CFS) i.e. heat denaturation and adsorption-desorption. In heat denaturation, the thermostable pediocin will remain soluble and can be observed in the supernatant while removing unconcerned proteins. From five different temperatures, the result of 80°C showed the highest inhibition zone. Remarkably, heating of CFS at 100°C and 120°C still showed antimicrobial activity during agar-well diffusion assay against L. monocytogenes with only a slight decrease in activity; thus, thermostable peptide might be involved. While the Bicinchoninic acid (BCA) assay showed an irregular pattern indicating that heat does not significantly affect the protein concentration. In adsorption-desorption, bacteriocin will attach to the cell at a pH of 6.5 and will be detached when adjusted to 2. The study found no antimicrobial activity from fermentation broth subjected to adsorption-desorption. Hence, the pediocin failed to be obtained through the adsorption-desorption and this method is not suitable for the pediocin synthesized by this specific P. acidilactici strain studied in this research. Future studies could include ammonium sulfate precipitation with optimum saturation percentage to further concentrate pediocin and detection of pediocin with Tricine-SDS-PAGE with 16% gel.