Characterization of the killer toxins secreted by mycocinogenic yeasts originating from Cibodas Botanical Garden

Abstract

Characterization of killer protein from 18 yeast strains isolated from Cibodas Botanical Garden were performed using Sodium Dodecyl Sulfate-Polyacrylamide Electrophoresis (SDS-PAGE), and by mycocinogenic activity test against 4 yeast isolates of coconut's milk contaminants and 4 yeast isolates of yogurt contaminants. The hhighest activity of mycocin was shown by Cryptococcus aethanolamini UICC Y-322, follwed by Candida rancensis UICC Y-326 and Cryptococcus aethanolamini UICC Y-379 respectively. The maximum activity of mycocin was obtained after the strains were in Killer Medium Broth, pH 4,4, for 3 days at 30'C and 110 rpm. The mycocin obtained was a protein which was inactive after heating at 1000 C. SDS-PAGE results showed that several dominant bands were observed at position of 23.4 kDa; 31.4 kDa; 56.7 kDa and 80 kDa. Specific bands of active mycocin from each strain could not be specified yet with bioautography test.