Nowadays increase demand energy causing decrease in fossil fule reservoir and causing the rising price. Therfore supply energy is one of imporsatnt global problem in the future renewable energy can be altenative suitable for fossil fule. In the present investigation result of methane production study on NaOH pretreated substrates of rapeseed straw. After determine of maximum and minimum temperature (25-125 °C), time (0-120 min) and concentration of NaOH (0-10% w/w) design expert software was used for perform of expremets. In the present investigation result of methane production study on NaOH pretreated substrates of rapeseed straw. Anaerobic digestion process was performed with mixed culture obtained from Isfahan North Wastewater Treatment sludge at mesophilic conditions at 37°C. Maximum methane production achieved from 5% w/w NaOH soulution, 75 °C and 60 min(277.3 mL/g VS) that shows 105% improvement in the methane yield compare to the raw material. Amount of R 2 adj and R 2 predict in this research were 0.8866 and 0.8041, respectively. SEM images of samples showed that the pretreated samples external surface area and their porosity were increased by pretreatment. Key words Alkali pretreatment, Biogas, Lignocellulosic materials, Anaerobic digestion
