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

Abstract

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 - 42oC 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 ml of CO2 in 6 h, respectively. Debaryomyces hansenii B-2 and Saccharomyces kluvveri K-6 each fermented 40% ((v/V) glucose at 30oC 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.