Indonesia is the largest country of oil palm production in the world. The oil palm by-product is still containing almost 80% of carbohydrates, such as cellulose and hemicellulose. This study aimed to optimize the enzymatic degradation of oil palm leaves in order to achieve zero waste of oil palm biomass by-product. Sodium hydroxide (NaOH) solution was used to isolate hemicellulose extraction from oil palm leaves. Various concentrations of NaOH such as 2 M, 2.5 M, 3 M, 3.5 M and 4 M and the reflux times of 2 hours, 4 hours, and 6 hours were used to optimize hemicellulose extraction. The optimum condition for hemicellulose extraction was 3 M NaOH and reflux time was 6 hours, while the yield at that condition was 48.94 % (w/w). The extracted hemicellulose is then hydrolyzed by a xylanolytic enzyme from recombinant Escherichia coli DH5α (namely pTP510). Temperatures of incubation were varied 50℃, 60℃, 70℃, and 80℃ for 24 hours at pH 6. The hydrolysis result was analyzed using High Performance Liquid Chromatography (HPLC). Xylose was produced at an optimum temperature of 60℃ (120.231 ppm), arabinose at 50℃ (26.265 ppm) whereas xylo-oligosaccharide at 50℃ (280.465 ppm).