Pretreatment with ammonia water for enzymatic hydrolysis of corn husk, bagasse, and switchgrass

Bagasse, corn husk, and switchgrass were pretreated with ammonia water to e nhance enzymatic hydrolysis. The sample (2 g) was mixed with 1-6 mt ammonia water (25-28% ammonia) and autoclaved at 120 degreesC for 20 min. After tr eatment, the product was vacuum-dried to remove ammonia gas. The dried soli d could be used immediately in the enzymatic hydrolysis without washing. Th e enzymatic hydrolysis was effectively improved with more than 0.5 and 1 mL ammonia water/g for corn husk and bagasse, respectively. In bagasse, gluco se, xylose, and xylobiose were the main products. The adsorption of CMCase and xylanase was related to the initial rate of enzymatic hydrolysis. In co rn husks, arabinoxylan extracted by pretreatment was substantially unhydrol yzed because of the high ratio of arabinose to xylose (0.6). The carbohydra te yields from cellulose and hemicellulose were 72.9% and 82.4% in bagasse, and 86.2% and 91.9% in corn husk, respectively. The ammonia/water pretreat ment also benefited from switchgrass (Miscanthus sinensis and Solidago alti ssima L.) hydrolysis.