A study on characterization of new bacteriocin produced from a novel strain of Lactobacillus spicheri G2 isolated from Gundruk- a fermented vegetable product of North East India

摘要

Bacteriocin producing Lactobacillus spicheri G2, isolated from Gundruk - a traditional fermented vegetable product of North East India. L. spicheri G2 identified by morphological, biochemical techniques followed by 16S rRNA gene technique. The 16Sr RNA sequence of bacteriocin producer is registered in NCBI under accession no. >JX481912. The bacteriocin producing potential of L. spicheri is being reported for the first time in the present investigation. Bacteriocin of L. spicheri G2 showed strong antagonism against food spoiling and pathogenic bacteria viz. Listeria monocytogenes, Staphlococcus aureus, Clostridium perfringens, Streptococcus mutans, Lactobacillus plantarum, Leuconostoc mesenteroides and Bacillus cereus. Bacteriocin production of L. spicheri G2 was enhanced by optimization of production time, pH of medium and incubation temperature by following one variable at a time method. Maximum bacteriocin activity (2000 AU/ml) was recorded in MRS broth at 34 h with an initial pH of 4.0 after incubating at 35 °C. The bacteriocin was purified by single step gel exclusion chromatography. Molecular weight of this novel bacteriocin was determined by SDS PAGE which was found to be 43 kDa. Purified bacteriocin was found resistant to high temperature and varied pH range but sensitive to proteolytic enzymes like trypsin and proteinase k, the characters desirable for food preservation.