Comparison of ethanol production from cassava chips by fermentation using five yeast strains
Keywords:cassava roots, ethanol, yeast strains
Although dried cassava chips are promising for production of fuel ethanol, relatively little has been done to optimize conditions for fermentation of this substrate. Studies were carried out to compare five yeast strains for ethanol production from cassava chips by fermentation. At the initial substrate concentration of 15%, Candida krusei strain TISTR 5624 optimally utilized reducing sugars within 24 h, with a theoretical yield of 98.66 %. Similar results were obtained with Saccharomycese cerevisiae strains TISTR 5027, TISTR 5596 and Saccharomyces carlsbergensis strain TISTR 5018. Candida tropicalis strain TISTR 5087 required 48 h to achieve equivalent yields. At 20% substrate, sugars were incompletely utilized by all strains tested, although maximal ethanol exceed 12% . At 25% substrate, both sugar utilization and ethanol production were severely impaired. Results provide useful guidelines for ethanol production from cassava chips by fermentation.
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