Lignin is a component of lignocellulosic materials which is relatively difficult to degrade. Its presence limits the use of lignocellulosic materials when they are converted to glucose and ethanol. This objective of the studi to reduce concentration of lignin contained in rice straw, carried out enzymatic hydrolysis and fermentation Pretreatment was carried out at a temperature of 100-140ºC and a NaOH concentration of 4-10% for 16 hours. Hydrolysis and fermentation separately with the addition of cellulase enzymes and Saccharomyces cereviceae during fermentation. The nutrients used for bacterial growth included (NH4)2HPO4 0.5 g/L, MgSO4.7H2O 0.025 g/L. The media then incubated for 15 hours in a shaker at 30°C. at 80 rpm. The results of the study achieved a decrease in lignin during 16 hours the percentage reduction in lignin concentration for variations in NaOH concentrations of 4, 6, 8 and 10% were 33.76, 44.96, 55.73 and 31.41%. The best conditions were achieved during the delignification time of 16 hours at a concentration of 8% NaOH, which was a 44.96% reduction in deligtnification. Hydrolysis and fermentation of rice straw that for 6 to 48 hours, resulted the percentage of increasing glucose and ethanol concentrations before and after pretreatment was 32.99% and 39.99%.