Cassava production has increased consistently in Ethiopia. Cassava contains toxic substances hydrogen cyanide. Another limitation, it has low content in protein. To conduct the study, five potential HCN tolerating yeast isolates were selected based on their tolerability capacity. Out of this yeast isolates, 28% Zygosaccharomyces spp (F9), 25% Saccharomyces cervices (F12) 17% Candidia Krusi (Cy4) 16% Candidia tropicals (Cy7), and 14% Candidia albicans (Cy6).Since cassava consumption needs some mechanisms to reduce the level of toxin and mechanism to improve protein prior to consumption, In this study, cassava flour was prepared and fermented with two inoculums level (1 and 2ml of 1.07x107to1.2x108) of with the above yeasts isolate from fermented cassava pulp juice and three fermentation times (24, 48 and 72hrs) was investigated. The pH, moisture and crud protein content of fermenting flour were also analyzed. It was found that the pH and moisture content of fermented samples after fermentation was reduced from 6.72 to 4.07 and 12.07 to 6.18% respectively. Sample fermented with isolate F9 and F12 at 2ml of inoculums level and 24hrs of fermentation time improved 85% and 78% respectively. In general, all the samples fermented with the yeast isolates improved protein content in range of 24 to 85% compared to the unfermented control (7%).

Keywords: Cassava Cyanide Tolerability, Yeast Isolates