Lactococcus lactis subsp. lactis LTM 32, a new bacteriocin-producing strain isolated from Vietnamese fermented milk
2001
Do, M.T. | Plockova, M. | Chumchalova, J. (Vysoka Skola Chemicko-technologicka, Prague (Czech Republic). Ustav Technologie Mleka a Tuku)
Screening for bacteriocin production of 60 strains of lactic acid bacteria (LAB) both isolated from various Vietnamese fermented food and obtained from the culture collection resulted in the detection of a bacteriocin-producing strain, Lactococcus lactis subsp. lactis LTM 32 isolated from Vietnamese fermented milk. This strain was identified and partly characterized. This bacteriocin inhibited not only closely relative strains of LAB but also strains of Listeria monocytogenes, Bacillus spp. including B. cereus, B. stearothermophilus, B. subtilis, B. pumilus and Staphylococcus aureus. It was heat stable at 121 deg C for 15 min, at 100 deg C for 120 min and stable during storage at -20 deg C and 4 deg C for 3 months. The bacteriocin was inactivated by some proteolytic enzymes, namely by proteinase K and pronase E in concentrations up to 0.5 mg/mL but not by alfa-amylase and pepsin. The optimal growth and bacteriocin production were achieved in M17L broth at 30 deg C and initial pH 6.8. The characteristics of bacteriocin-producing strain Lactococcus lactis subsp. lactis LTM 32 are of interest for food safety.
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