Molecular Identification and Potential Ethanol Production of Long-term Thermo-tolerant Yeast Candida Tropicalis

Abstract

Candida tropicalis is an organism capable of promoting the fermentation process of starch media supplementation with α-amylase sufficient to produce ethanol. This study aims to identify Candida tropicalis yeast and the potential for ethanol production which is tolerant at high temperatures. Molecular identification methods using Molecular rDNA sequencing and measurement of ethanol production at the incubation rate of yeast growth at 38°C, 39°C and 40°C. The best isolates used were JCBI-23 and JCBI-24 from Indonesia and DMKU-3 thermo tolerant yeast control isolates Kluyveromyces marxianus. The results showed that molecular identification of JCBI-23 isolate was Candida tropicalis culture CBS: 2424 large subunit of ribosome RNA gene with an identification value of 99% and JCBI-24 isolate was Candida tropicalis isolate 4kr27 26S ribosome RNA gene with an identification value of 96%. Based on the growth resistance test, isolates showed that optimum growth occurred during seven-day incubation period and tend to decrease its growth on day 14, both at 37°C, 38°C and 39°C. The best ethanol production at 37°C and not significantly different from the controlled isolates, and showed ethanol production tend to be constant on day 48, both at 37 and 40°C.