Diversity of yeasts in otch, a traditional starter used in fermentation of an opaque sorghum beer chakpalo

摘要

Sorghum beer is a significant diet component of millions of poor rural communities in sub-Saharan Africa. In this study, we identified and biochemically characterized yeast strains isolated from otchè, a traditional starter used in fermentation of chakpalo, an opaque sorghum beer in Benin. 12 samples of otchè were collected from 12 different commercial processing sites. The mean values of pH, titratable acidity, dry matter content and refractive index of the starters analyzed were 3.37, 0.17 (% as lactic acid), 7.15 and 7.0%, respectively. The mean yeast count per sample was 8.72 log cfu/ml. Based on phenotypical and biochemical characterization (carbon and nitrogen assimilation) profile, 50 yeast strains were identified and found to belong to five genera and ten species. Saccharomyces cerevisiae was found to be the most predominant yeasts species of otchè.