ISOLATION, BIOCHEMICAL PROPERTIES AND APPLICATION OF BACTERIOCINS FROM PEDIOCOCCUS PENTOSACEOUS ISOLATES

Bacteriocins are ribosomally synthesized peptides having considerable potential as a food preservative because of their strong antagonistic activity against many food spoilage and pathogenic organisms. Bacteriocins from Pediococcus pentosaceous isolates, DFR-JJ1 and DFR-JJ6, were purified using cold-acetone precipitation, cell adsorption-desorption and gel permeation chromatography techniques. Cold-acetone fractionation resulted in higher yields of bacteriocins, but the specific activity and fold purification were higher for cell adsorption-desorption and gel permeation chromatography. Both bacteriocins JJ1 and JJ6 exhibited broad inhibitory spectrum against foodborne pathogens and spoilage microorganisms, including some Gram-negative bacteria. Amylase, lipase and catalase did not alter the antimicrobial activity but proteolytic enzymes inactivated these bacteriocins. They were heat stable and exhibited activity in a pH range of 2–8 with maximum activity between pH 4.0 and 5.0. Molecular weights of bacteriocin JJ1 and JJ6 were found to be ∼4.95 and 4.3 kDa, respectively. PRACTICAL APPLICATIONS Bacteriocins of lactic acid bacteria have been found to kill or inhibit the growth of foodborne pathogens and spoilage microflora, and hence, can be used as natural preservatives in the production of foods with enhanced shelf life and/or safety. With the emergence of antibiotic-resistant Gram-positive pathogenic bacteria, the possibility of bacteriocins as supplements or replacements for antibiotics for therapeutic use is also being considered. Of all the antimicrobial peptides, very few have been used as preservatives in the food industry and/or as antibiotic substances in medicine. However, an increasing number of bacteriocins are being tested in model systems, some of them show promising results and may reach commercial acceptance in the near future. In the present study, two bacteriocins from Pediococcus pentosaceous strains were purified, which inhibited the growth of Staphylococcus aureus in liquid medium and Salmonella typhimurium in orange juice, justifying their potential as food biopreservatives.