PRODUCTION OF ANTIFUNGAL SUBSTANCE BY LACTOCOCCUS-LACTIS SUBSP LACTISCHD-28.3

Six of the 2100 colonies of lactic acid bacteria isolated from 4 month old Cheddar cheese and raw buffalo milk showed antifungal activity ag ainst Aspergillus flavus IARI when tested by the well agar diffusion a ssay on Potato Dextrose Agar containing 0.1% Triton X-100. Out of thes e, the most promising isolate having a broad spectrum of antifungal ac tivity including Aspergillus flavus IARI, A. flavus NCIM 555, A. paras iticus NCIM 898 and Fusarium spp. was identified as Lactococcus lactis subsp. lactis CHD-28.3. Among the mold cultures used as indicator str ains. the most sensitive towards antifungal substance produced by the test culture was A. flavus IARI. The cell-free supernatant of the test culture in Elliker's broth adjusted to pH 6.8 produced an inhibition zone of 15-19 mm against A. flavus IARI, A. flavus NCIM555 and A. para siticus NCIM898. The isolate when grown at 30 degrees C for 48 h in El liker's broth showed optimum antifungal activity. When the supernatant was neutralized to pH 7.0 or 7.5. there was little reduction in activ ity. However, after enzymatic treatment of supernatant with chymotryps in, trypsin and pronase E, the antifungal activity disappeared which i ndicated the proteinaceous nature of the antifungal substance.