摘要
生物燃料将成为主要新能源之一,以玉米芯为原料,碱氧和稀酸为处理剂对其进行2步法预处理,使原料中纤维素相对含量增加,以提供转化乙醇的纤维素原料。采用扫描电镜表征2步法预处理玉米芯,其表面形成疏松、沟纹和孔洞形态,这有利于酶解。采用瑞氏木霉生产的纤维素酶水解该预处理玉米芯,利用正交实验得到酶水解优化条件为,酶用量75 FPU g 1,底物质量浓度60 g L 1,pH值4.8,反应温度50℃,还原糖得率可达69.3%。为提高纤维素酶中β-葡聚糖酶的酶活效率,并减少产物葡萄糖对β-葡聚糖酶的抑制作用,进一步优化β-葡聚糖酶加量。结果表明,当β-葡聚糖酶加量达6.5 CBU时,还原糖得率显著提高到78.2%。这表明该预处理玉米芯是有效降解的玉米芯原料,适于提高还原糖得率。
Bio-fuel has become one of the most important sustainable energies. In this paper, corn cob was pretreated with two-step method including alkaline/oxidative and dilute sulphuric acid pretreatment process. This pretreatment has increased the content of cellulose, and provided the material of ethanol production. SEM shows that the surface of pretreated corn cob has porous morphology, which is benefit for enzymatic hydrolyzation. The pretreated corn cob was hydrolyzed by the cellulase produced from Trichodema reesei. Factors of enzyme dosage, pulp concentration, reaction temperature and pH value on its hydration behavior were investigated. The conditions optimized by orthogonal experiments are as follows： enzyme dosage is 75 FPU·g^-1, pulp concentration is 60 g·L^-1, pH value is 4.8, reaction temperature is 50℃. Under above conditions, the enzymatic hydrolyzation yield is 69.3%. Addition of β-glucosidase to enzymatic hydrolyzation of various lignocellulosic substrates can enhance its hydrolyzation efficiency and decreased the inhibitory effect of glucose on β-glucosidase. Furthermore, as β-glucosidase was added to enzymatic hydrolyzation of pretreated corn cob, the cellulose enzymatic hydrolyzation yield was enhanced to 78.2% when the added β- glucosidase dosage is 6.5 CBU. These results prove that the proposed two-step method is effective on corn cob conversion to ethanol.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2013年第2期236-242,共7页
Journal of Chemical Engineering of Chinese Universities
基金
中国石油大学(北京)科研基金(QZDX-2010-04)
国家自然科学基金(21076229
51274223)
国家重大专项(2011 X 05009-005)
关键词
玉米芯
纤维素酶
糖化水解
还原糖得率
corn cob
cellulose enzyme
enzymatic hydration
fermentation sugar yield
