Optimization of glucose production from corncob by microwave-assisted alkali pretreatment and acid hydrolysis

The production of reducing sugar is the most crucial process in the production of cellulosic ethanol and can be divided into two steps. First, pretreatment removes the unwanted constituents of lignocellulose to produce cellulose; then the cellulose is hydrolyzed to glucose (a reducing sugar) in the hydrolysis step. In this work, microwave heating was applied for both alkali pretreatment and sequential acid hydrolysis of corncob in which the conditions were optimized by response surface methodology. The optimal cellulose content in the pretreated corncob was 52.9 % w/w obtained with 1 M sodium hydroxide using a 1:12 weight ratio of corncob to solution at 900 W microwave power for 20 min, which was used to optimize the glucose yield in the following step. The highest yield of 14.8% glucose was achieved with 1.3% w/w sulfuric acid solution at 900 W for 16 min.