Enhanced saccharification of sugarcane bagasse by the optimization of low concentration of NaOH and ammonia pretreatment

•High concentration and yield of total reducing sugar.•A lower concentration of sodium hydroxide was used in the pretreatment scheme.•The pretreatment solution and the recovered ammonia water can be reused for effective pretreatment. In this study, sugarcane bagasse (SCB) was developed as raw material for pretreatment, enzymatic hydrolysis and fermentation by the mixture of NaOH with ammonia. By optimizing the parameters with response surface methodology, the maximum total reducing sugar concentration (TRSC) and the total reducing sugar yield (TRSY) were obtained. After optimization, the TRSC was 16.23 g/L (Optimized-P1: 25 % ammonia, 1.5 % NaOH, 160 ℃, 2 h) and the TRSY was 0.46 g/g (Optimized-P2: 24 % ammonia, 1 % NaOH, 150 ℃, 2 h).