In order to evaluate the suitability of production of ethanol from the microwave-assisted alkali pretreated wheat straw, the simultaneous saccharification and fermentation (SSF) of the microwave-assisted and conventional alkali pretreated wheat straw to ethanol were optimized and compared using cellulase from Trichoderma reesei and Saccharomyces cerevisiae YC-097 cells. The SSF optima for the microwave-assisted alkali pretreated wheat straw were 100 g 1(-1) substrate, 40 degrees C, 15 mg [cellulase] g(-1) [substrate], initial pH 5.3 and 72 h. Under the above optimum conditions, the ethanol concentration reached 34.3 g 1(-1) and the ethanol yield was 69.3%. The SSF optima for the conventional alkali pretreated wheat straw were 100 g 1(-1) substrate, 40 degrees C, 20 mg [cellulase] g-1 [substrate], initial pH 5.3 and 96 It. Under its optimum conditions, the ethanol concentration and the ethanol yield were 31.1 g1(-1) and 64.8%, respectively. It was obvious that production of ethanol from microwave-assisted pretreated wheat straw had lower enzyme loading, shorter reaction time and could achieve higher ethanol concentration and yield than from the conventional alkali pretreated wheat straw. The microwave-assisted alkali pretreatment was an efficient pretreatment method of wheat straw for its ethanol production. (c) 2005 Elsevier Ltd. All fights reserved.