ethanol production

African Journal of Biotechnology Vol. 7 (20), pp. 3749-3752, 20 October, 2008
Available online at http://www.academicjournals.org/AJB
ISSN 1684–5315 © 2008 Academic Journals

Full Length Research Paper

Ethanol production potential of local yeast strains isolated from ripe banana peels
A. A. Brooks
Department of Microbiology, University of Calabar, P.M.B. 1115, Calabar, Nigeria.
E-mail: [e-mail]. Tel: [phone].
Accepted 16 May, 2008

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 v o v 6 - 12% ( /V) ethanol, fermentatively active at 37 - 42 C and fermented 40% ( /V) glucose. S. cerevisiae T-7 and S.cerevisiae R-2 showed rapid fermentative activity on maltose by liberating 150 and 120 µl of CO2 in 6 h, respectively. Debaryomyces hansenii B-2 and Saccharomyces kluvveri K-6 each fermented 40% v o
(( /V) glucose at 30 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.
Key words: Banana peels, ethanol, yeast, fermentation, starch.
INTRODUCTION
The increasing demand for ethanol for various industrial purposes such as alternative source of energy, industrial solvents, cleansing agents and preservatives, has necessitated increased production of this alcohol. Ethanol production is usually accomplished by chemical synthesis of petrochemical substrates and microbial conversion of carbohydrates present in agricultural products. Owing to the depleting

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