Defatted microalgal biomass is one of the most promising third generation feedstock for biofuel production due to the contains considerable amounts of total reducing sugars than can be used as source for ethanol production by separate hydrolysis and fermentation. In the present study the defatted microalgal biomass of Nannochloropsis limnetic was acid pre treated and used as feedstock for ethanol production by Saccharomyces cervevisiea. The maximum yield of glucose 76.22±0.04 % obtained by acid pretreatment. The hydrolysate derived by acid pretreatment was used as substrate for ethanol production by S. cervevisiea and obtained the maximum ethanol 48.01±0.02 gL-1 with pH 4.0, at 30o C and 200 rpm. The results demonstrated that the defatted biomass of N. limnetica can be efficiently acid (H2SO4) pretreated to obtain high amount of fermentable sugars for enhanced yield of ethanol production at the optimum conditions.
