Isolation, Identification and Characterizationof Bacteriocin from Lactobacillus Lactis

Abstract

Many consumers today are concerned about the synthetic chemicals used as preservatives in food, and there is a resulting trend towards less processed food. Bacteriocin produced by Lactobacillus lactis strain isolated from the marine environment, showed broad range of antibacterial activity against some major food borne pathogens. Sediment samples were collected at Parangipettai coast and stored in the laboratory at 4ºC for used to isolate the Lactobacillus spp. The samples were diluted and plated on the de Rogosa and Sharpe agar and The isolated strain was grown in MRS broth (pH-6.0) seeded with 5% inoculum of overnight culture and maintained anaerobically at 30ºC for 48 h. After incubation, cells were removed from the growth medium by centrifugation. The cell-free
supernatant was adjusted to pH 6.0 using 1N NaOH and it was used as crude bacteriocin (14). Maximum bacteriocin production was observed at 30°C, pH 6.0 and 1.5% sodium chloride solution. The enzymes - amylase,
DNase, RNase and lipase had a positive effect on bacteriocin production. Proteinase K and pepsin strongly inhibited bacteriocin production. Among detergents, Sodium dodecyl sulphate (SDS), Tween 80 and Tritone X-100
stimulated bacteriocin production. EDTA and urea strongly inhibited bacteriocin production. The molecular weight was 94 kDA. Therefore, the peculiar antimicrobial characteristics of L. lactis can positively have impact on their use as starter cultures for traditional fermented foods, with a view to improving the hygiene and safety of the food products so produced.