Strain improvement of Lactobacillus plantarum for production of bacteriocin and their purification and characterization
Mohammed Ali Hussein
The Five LAB was isolated and screened from 20 different sample sources. Among these two LAB found efficient producer of bacteriocin. Bacteriocin producing LAB was then screened on de Man Rogosa and Sharpe agar (MRS) medium. Morphological, biochemical, physiological characteristics and antimicrobial activity were preliminary examined. Antimicrobial activity of the 2 identified bacteriocin-producing LAB isolates were quantified by disc diffusion method against pathogens like S. typhimurium, E.coli, Shigella flexneri, Staphylococcus aureus and Proteus vulgaris. The efficient bacteriocin producer was identified as Lactobacillus plantarum. This was selected for the enhancement of activity by different factors like UV radiation, pH variation, temperature variation, Acridine orange and Ethidium bromide exposure. The decreasing order for the antimicrobial activity enhancer can be dictated as UV radiation, pH and temperature variation, Acridine orange and Ethidium bromide respectively. UV radiation found to be effective agents amongst others for enhancement the antimicrobial activity against various pathogens. Improved strain of Lactobacillus plantarum was then used for the production of bacteriocin and partial purification by salting out method.