IDENTIFICATION OF LACTOCOCCUS PD14 PRODUCING BACTERIOCIN

Abstract

The strain PD14 was isolated from cow's fresh milk of Phu Dong farm, Gialam, producing a bacteriocin at high level and its properties are  very similarity to nisin. The inhibition activity determination of  the strain PD14 to test- microorganism showed that the crude extract exhibited strongly against  Lactobacillus plantarumJCM1149. Study the effects of various proteolytic enzymes on antibacterial activity revealed the raw  bacteriocin was completely inactivated by  α-chymotrypsin and the activity remained to 100 % in  case of trypsin and 65 % by pepsin. The amplification and sequence analysis of gene 16S rRNA combined with morphological characterization and biochemical tests by API 50 CHL demonstrate strongly the strain PD14 belongs to Lactococcus lactis subsp. lactis.