The biodiversity and the killer activity of yeasts isolated from various types of
fermented food in Malaysia were investigated in this study. Of 252 yeasts isolated from 48
fermented food samples in this study, 19 yeast species were identified based on sequence
analysis of the ITS1-5.8S-ITS2 partial fragments of the yeasts. A total of 29 (11.5%) of the
yeast isolates demonstrated killer activity to at least one Candida species tested in this
study; including 22 isolates of Trichosporon asahii, 4 isolates of Pichia anomala, and one
isolate each of Pichia norvegensis, Pichia fermentans and Issatchenkia orientalis,
respectively. The presence of killer yeasts reflects antagonism that occurs during microbial
interaction in the fermented food, whereby certain yeasts produce killer toxins and possibly
other toxic substances in competition for limited nutrients and space. The anti-Candida
activity demonstrated by killer yeasts in this study should be further explored for development
of alternative therapy against candidiasis.