Production of ethanol (bioethanol) by fermentation is one of the main ways to reduce the consumption of crude oil, beside less environmental pollutions. Bioethanol is the most suitable component for mixing with gasoline since it has a high octane number and low cetane number. Microorganism is one of the key factors in biological production of ethanol. In this research, Mucor hiemali s was used for ethanol production. The fungus in preliminary experiments showed a high yields for ethanol production. The fermentation performed under anaerobic condition and the fermentation media were alanlized by HPLC. The main gol of this work was optimization of the media for efficient production of ethanol and biomass by M. hemialis . Experimental design was used for optimization by statistical analysis software, MINITAB, using surface methodology design and factorial design. Effects of different components were optimized in synthetic media. It was found that the trace metal solution, ZnSO 4 and vitamin solution dose not have siginificant effects on ethanol yield. It was also determined that K 2 HPO 4 , MgSO 4 , (NH 4 ) 2 SO 4 and CaCl 2 had low effects on the ethanol yield. The most effective materials in ethanol yield were glucose and yeast extract. The optimized value of yeast extract was found to be 4 g/l and the ethanol yield in a solution of 4 g/l of yeast extract and 30 g/l of glucose, was determined 0.46 gram per gram of consumed glucose. Optimization of glucose concentration performed by enzymatic wheat flour hydrolyzates. The most important side product in the medium was glycerol with the maximum yield of 0.07 gram per gram of consumed glucose. However, the maximum yield of biomass was determined 0.16 gram per gram of consumed glucose. The yield variation of glycerol was between 0.02 – 0.07 gram per one gram of consumed glucose. The optimum of temperature, time and pH were determined as 30° C, 36 h and 5, respectively.
