ABSTRACT
The aim of this work was to study the optimiation of co-culturing of Trichoderma sp. and Saccharomyces cerevisiae (1:4 ratio) on sweet potato (Ipomoea batatas L.) flour (SPF) for the production of bio-ethanol in solid-state fermentation (SSF). Maximum ethanol (172 g/kg substrate) was produced in a medium containing 80% moisture, ammonium sulphate 0.2%, pH 5.0, inoculuted with 10% inoculum size and fermented at 30ºC for 72h. .Concomitant with highest ethanol concentration, maximum ethanol productivity (2.8 g/kg substrate/h), microbial biomass (23×10(8) CFU/ g substrate), ethanol yield (47 g/100g sugar consumed) and fermentation efficiency (72%) were also obtained under these conditions. Cell interaction was observed familiar between the viable cells of Trichoderma sp. and S. cerevisiae when co-cultured. Ethanol production ability by the co-culture was 65 % higher than the single culture of S. cerevisiae from un-saccharified SPF.