SCREENING OF YEASTS FROM BRAZILIAN AMAZON RAIN-FOREST FOR EXTRACELLULAR PROTEINASES PRODUCTION

Eighty seven yeast strains representing 34 species isolated from Parah ancornia amapa fruit and associated Drosophila flies collected in the Brazilian Amazon rain forest, were screened for proteinase production. Proteolytic activity was tested through casein hydrolysis in solid me dium supplemented with 0.5% casein and glucose. Among 23 strains, 18 f rom genus Candida and 5 from Pichia were caseinolytic and produced pro teinases in yeast carbon base liquid medium supplemented with casein 0 .01%. The proteolytic activity was tested on pH ranging from 2.0 to 9. 0 in correspondance to the pH of the cultures media in which the yeast s were grown. Six highly proteolytic strains: Candida parapsilosis AP1 53A, C. krusei AP176, C. sorbosa DR215, C. sorbosa AP259, C. valida AP 209A and C. sorboxylosa AP287 were selected and the pH optima of produ ction and the proteolytic activity were determined. In general the sec retion of proteinase was maximum throughout the exponential and the st ationary phases. Greater production occurred in acidic culture and hig h activity was observed at pH 3.0, 4.0 and 5.0.