Cellulase-producing yeast isolated from fermented cocoa beans as biocontrol for pathogenic mold chocolate fruit collected from Sentul, Jawa Barat, Indonesia

Abstract

Mold is one of the microorganisms that can cause damage in chocolate fruit by producing phytopathogenic toxins. Until now, pesticides have been widely used for controlling postharvest loss in fruit. Yeasts can produce secondary metabolites, which can inhibit the growth of pathogenic mold. In this study, we isolate, identify, and apply yeasts isolated from fermented cocoa beans to control the growth of pathogenic mold in chocolate fruit collected from Sentul, Indonesia. This research includes yeast isolation using the dilution method with YMA medium, mold isolation using direct planting method on PDA medium, screening ability to produce cellulase using diffusion method on CMC medium, and in-vitro antagonist testing using dual culture method on PDA medium. The results showed that 128 yeast isolates and 37 mold isolates were obtained in this study. The results of screening representative cellulase capability of 77 yeast obtained 6 positive yeast isolates produced cellulase with the highest cellulolytic index of 0.23-0.30. The 6-yeast antagonism test with the highest cellulolytic index showed that C3.3.1 isolate had the best ability to inhibit pathogenic molds with 37.36% inhibitory power.