| Abstract | A potato wastes powder utilizing bacteria was isolated from soil. Based on morphological, physiological and 16S rDNA, this bacterium was identified as Bacillus subtilis. Inoculation of the solid state culture on potato wastes powder at pH 6.5 with 20% inoculum size of B. subtilis at 30?C resulted in the maximum biomass and amylase activity. The maximum biomass of B. subtilis and its amylase production was achieved in the stationary phase; -amylase production coincided with the increase in the specific growth rates of the cultures and reduction of starch content in potato wastes powder. B. subtilis was able to degrade starch content in solid potato wastes completely in solid state culture at pH 6.5 and 30 °C after 4 days. Potato wastes powder exhibited different susceptibilities towards amylase to their conversion to reducing sugars. The present study showed also that, the general trend of potato wastes powder bioconversion with B. subtilis amylase was more than the general trend by B. subtilis. This enzyme effectively led to enzymatic conversion of B. subtilis pretreated starch from potato wastes powder into glucose, followed by fermentation into ethanol. Maximum ethanol production from the hydrolysate of potato wastes powder was at 30 °C, pH 4.5 and inoculum size 10 % after 3 days of incubation. The utilization of amylase and Saccharomyces cerevisiae for ethanol production from the potato wastes under the optimum conditions can not only utilized for cheap clean energy production, but also for getting rid of some undesired wastes. |