Oil palm trunk chip, pretreated by steam explosion was used as a substrate for hydrolysis. The pulp was further submitted to delignification by sodium hydroxide compared with potassium hydroxide solution. The enzymatic hydrolysis of delignified pulp was performed using a commercial cellulase containing -glucosidase enzyme. Response surface methodology was used for optimization of delignification and hydrolysis processes. Comparative results with and without a delignification step, influenced on hydrolysis process, were presented. Both enzymatic hydrolysis processes (with delignification) gave a higher glucose yield than the hydrolysis process without delignification. The glucose solution obtained from three hydrolysis processes were fermented to produce ethanol.