Improvement of the Enzymatic Hydrolysis of Bamboo by White Liquor and Alkaline Sulfite Pretreatments

The performance of white liquor (NaOH and Na2S) and alkaline sulfite (Na2SO3 and NaOH) pre-treatments on improving the enzymatic hydrolysis of bamboo were investigated. The results showed that more than 96.5% of the lignin removal was achieved when the bamboo was treated with white liquor pretreatment (20% NaOH and 20% Na2S of dry substrate) and alkaline sulfite pretreatment (20% NaOH and 20% Na2SO3 of dry substrate) at 180 degrees C for 1 h. After a 48 h enzymatic hydrolysis with 15 FPU/g-glucan for cellulase, 30 IU/g-glucan for beta-glucosidase, the cellulose-to-glucose conversion yield (CGCY) increased from 14.8% to 100.0%, respectively. The results indicated that the lignin could be effectively removed during pretreatment. Additionally, a strong correlation between the delignification and the reducing sugar yield (or CGCY) was observed by this pretreatment method. These results evidently support that the white liquor and alkaline sulfite pretreatments are both effective and feasible methods for bioethanol processing bamboo resources.