Polyphasic identification of yeasts with amylolytic, lipolytic, proteolytic, and fruit-rot mold antagonizing activities isolated from ripe mango (Mangifera indica L.) and banana (Musa X paradisiaca L. varieties)
2010
Tan Gana, N.H., Philippines Univ. Los Baños, College, Laguna (Philippines)
Three hundred eighty-seven yeast strains were isolated from different banana and mango varieties bought from the Calamba Public Market and Divisoria Market. Isolation was done by plating washings in Yeast Extract Malt Extract Agar and Ethanol Sulphide Agar supplemented with 100 ppm streptomycin and 10 ppm biphenyl. The yeast were screened for amylolytic, dipolytic, and proteolytic activity on Starch Agar, Sierra's Medium and Casein Agar, respectively. Yeasts with amylolytic, lipolytic and proteolytic activities numbered 80, 176 and 80, respectively. One hundred eighty-five yeast isolates were tested for their in vitro antagonistic activity against the fruit-rotting molds Aspergillus niger (Biotech 3261), Penicillium expansion (BIOTECH 3097) and Colletotrichum sp. (BIOTECH 33091). Only two isolates showed antagonism towards the control organisms. Fifty one yeasts with high and/or with multiple enzymatic activities and/or with mold antagonistic activity were selected for identification. Evaluation of the data obtained from the phenotypic identification and sequence analysis was undertaken to obtain a consensus identity for the isolates. Based on the available taxonomic data, the yeasts with the enzymatic activities assayed for were identified as: Aureobasidium pullulans var melanogenum, Aureobasidium sp., Candida haemulonii, Cryptococcus sp., Debaryomyces nepatensis, Kodamaea ohmeri, Hypopichia burtoni, Hypopichia sp., Pseudozyma hubeiensis, P. pruni and P. prolifica while the yeasts with mold-antagonistic activity were identified as Pseudozyma hubeiensis and Candida orthopsiloses. This study is probably one of the first to characterize the yeast microflora of bananas and mangoes in the country. It has provided a snap shot of the yeast diversity which can be found in these fruits. The isolates gathered in this study will undoubtedly prove to be important biological or biotechnological resources in the country.
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