Isolation, screening and identification of ethanol producing yeasts from Ethiopian fermented beverages
Dagnew Bitew, Anteneh Tesfaye, Berhanu Andualem
Abstract
The growing demand for renewable energy sources such as bioethanol is facing a lack of efficient ethanologenic microbes. This study aimed to isolate and screen ethanologenic yeasts from Ethiopian fermented beverages. A progressive screening and selection approach was employed. Selected isolates were evaluated for bioethanol production using banana peel waste as substrate. A total of 102 isolates were obtained. Sixteen isolates were selected based on their tolerance to stress conditions and carbohydrate fermentation and assimilation capacity. Most found moderately tolerant to 10%, but slightly tolerant at 15 and 20% (v/v) ethanol concentration. They yield 15.3 to 20.1 g/L and 9.1±0.6 to 12.9±1.3 g/L ethanol from 2% (w/v) glucose and 80 g/L banana peel, respectively. Molecular characterization identified them as Saccharomyces cerevisiae strains. Results demonstrate insight about their potential role in the ethanol industry. Optimization of the fermentation conditions is recommended.