Wheat straw biode gradability during anaerobic digestion was improved by treatment with potassium hydroxide (KOH) to decrease digestion time and enhance biomethane production and fertility value. KOH concentrations of 1% (K1), 3% (K2), 6% (K3) and 9% (K4) were tested for wheat straw pretreatment at ambient temperature with a C:N ratio of 25: 1. 86% of total solids (TS), 89% of volatile solids (VS) and 22% of lignocellulose, cellulose and hemicellulose (LCH) (22%) were decomposed effectively with the wheat straw pretreated by 6% KOH. Enhanced bio-gas production and cumulative biomethane yield of 258 ml.(g VS)(-1) were obtained increased by 45% and 41% respectively, compared with untreated wheat straw. Pretreated wheat straw digestion also yielded a digestate with higher fertilizer values potassium (138%), calcium (22%) and magnesium (16%). These results show that TS, VS and LCH can be effectively removed from wheat straw pretreated with KOH, improving biodegradability biomethane production and fertilizer value. (c) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.