摘要：The aims of this research were to know the best concentration of onggokflour to produce maximum reduction sugar concentration by Aspergillusniger and efficiency of ethanol production from reduction sugar as theproduct of onggok flour saccharification by Zymomonas mobilis, and theethanol concentration which produced. The framework of this research wascassava starch in onggok can be used as substance which yielded ethanol byfermentation. The ethanol yielded serves as an alternative substitution fuelfor fossil fuel. This research was done in two stages; they weresaccharification by A. niger and ethanol fermentation by Z. mobilis. Atsaccharification stage there were four level of onggok flour concentration:10%, 20%, 30% and 40%. The inoculum concentration of A. niger 10% (v/v)and the amount of spore about 3.3x106 spore/mL, was inoculated eachconcentration of onggok flour, with the temperature of incubation 500C andthis process taken five days. Parameters have been used were starchconcentration before and after saccharification process, reduction sugarconcentration, and pH conducted by each, every 24 hours. Stage of ethanolfermentation used concentration of Z. mobilis 10% (v/v), with the cellamount 5.1x107 cell/mL. Reduction sugar concentration fromsaccharification product that used 1.9352% and fermentation was done in 72hours. Parameters were concentration of ethanol and reduction sugar each,every 24 hours and the growth of Z. mobilis cell every 24 hours. Thisresearch concluded that concentration of onggok flour 10% producedmaximum reduction sugar concentration on the third day that was 1.1842%.Ethanol concentration yielded was 0.7% (v/v) and efficiency of ethanol thatwas produced from reduction sugar from saccharification of onggok flourwas 83% during 72 hours fermentation
