BACKGROUND: The objective of this work is to develop an efficient pretreatment method that can help enzymes break down the complex carbohydrates present in wheat straw to sugars, and to then ferment of all these sugars to ethanol. RESULTS: The yield of sugars from wheat straw (8.6%, w/v) by lime pretreatment (100mg g(-1) straw, 121 degrees C, 1 h) and enzymatic hydrolysis (4S degrees C, pH 5.0, 120 h) using a cocktail of three commercial enzyme preparations (cellulase, beta-glucosidase, and xylanase) at the dose level of 0.15 mL of each enzyme preparation g(-1) straw was 568 +/- 13 mg g(-1) (82% yield). The concentration of ethanol from lime pretreated enzyme saccharified wheat straw (78 g) hydrolyzate by recombinant Escherichia coli strain FBRS at pH 6.5 and 35 degrees C in 24 h was 22.5 +/- 0.6 g L-1 with a yield of 0.50 g g(-1) available sugars (0.29 g g(-1) straw). The ethanol concentration was 20.6 +/- 0.4 g L-1 with a yield of 0.26 g g(-1) straw in the case of simultaneous saccharification and fermentation by the E. coli strain at pH 6.0 and 35 degrees C in 72h. CONCLUSION: The results are important in choosing a suitable pretreatment option for developing bioprocess technologies for conversion of wheat straw to fuel ethanol. (c) 2007 Society of Chemical Industry.