Ethanol production potential of local yeast strains isolated from ripe banana peels

The ability of different yeast strains isolated from ripe banana peels to produce ethanol was investigated. Of the 8 isolates screened for their fermentation ability, 5 showed enhanced performance and were subsequently identified and assessed for important ethanol fermentation attributes such as ethanol producing ability, ethanol tolerance, flocculence, thermo- and osmo-tolerance. Saccharomyces cerevisiae R-8 exhibited the best attributes for ethanol production by being highly flocculent, tolerant to 6-12% ((v)/V) ethanol, fermentatively active at 37 - 42 degrees C and fermented 40% ((v)/V) glucose. S. cerevisiae T-7 and S. cerevisiae R-2 showed rapid fermentative activity on maltose by liberating 150 and 120 mu l of CO2 in 6 h, respectively. Debaryomyces hansenii B-2 and Saccharomyces kluvveri K-6 each fermented 40% (((v)/V) glucose at 30 degrees C to yield 3.6 and 5.8% ethanol, respectively. The five yeast strains are therefore potential candidates for ethanol production from banana peels or other local starch sources.