Organosolv pretreatment of wheat straw for efficient ethanol production using various solvents

Five solvents with different physicochemical properties were evaluated for organosolv pretreatment with wheat straw (Triticum durum Desf.). Ethanol, methanol, butanol, acetone and diethylene glycol, were used, in the presence of 23 mol m−3 sulfuric acid as the pretreatment's catalyst. The pretreatment process was conducted at different temperatures and times. The enzymatic digestibility of the pretreated material was estimated by using a commercial cellulase preparation prior to fermentation of released glucose by Saccharomyces cerevisiae. The pretreatment with ethanol at 180 °C for 40 min resulted in a maximum cellulose conversion of 89%, as well as ethanol yield 67% of theoretical yield. The results indicate that organosolv pretreatment with diethylene glycol at 160 °C for 40 min is also very promising due to its high ethanol yield of 65% combined with high pulp yield of 51%.