纤维素酶系碱性条件下的选择性失活及应用  

Selective denaturation of major enzymatic components in cellulase system by alkali treatment and its application

作　　者：徐勇[1,2,3] 蔡鹏[1,2,3] 范丽[1,2,3] 杭琪[1] 勇强[1,2] 余世袁[1,2] 

机构地区：[1]南京林业大学化工工程学院,江苏南京210037 [2]林木遗传与生物技术教育部重点实验室,江苏南京210037 [3]江苏省生物质绿色燃料与化学品重点实验室,江苏南京210037

出　　处：《食品工业科技》2012年第21期164-167,171,共5页Science and Technology of Food Industry

基　　金：林业公益项目(200904017);国家自然科学基金项目(31070514);江苏省重大科技支撑项目(BEK2011838);江苏省高校科技创新团队资助项目;江苏省高校优势资源学科建设工程资助项目

摘　　要：里氏木霉产纤维素酶系中的内切葡聚糖酶(CMCase)、纤维二糖水解酶(CBH)和β-葡萄糖苷酶三大酶类在碱性处理条件下会发生快速、选择性失活。在pH9.00和(25±1)℃的条件下静置处理纤维素酶液30min,CMCase和CBH酶组分主要发生可逆变性失活,而β-葡萄糖苷酶发生不可逆变性失活,它们的残余酶活力分别为58.8%、56.6%和5.7%,相对比例可达到10.3和9.9。通过碱性处理能够得到低β-葡萄糖苷酶活力的纤维素酶制剂,可以显著提高其定向酶水解纤维素制备纤维低聚糖的生产性能,并生成以纤维二糖为主包括少量纤维三糖的纤维低聚糖。以0.1%(v/v)碱处理纤维素酶定向水解10g/L纸浆24h,纤维低聚糖的酶解得率为6.73%,占总糖类的78.2%,比天然酶反应体系提高53.6%。In the crude cellulase system of Trihcoderma reesei, three main enzyme groups involving endo- glucanase（CMCase） ,cellobiohydrolase（CBH）and β-Glucosidase were rapidly and selectively denatured in the alkali circumstance. CMCase and CBH were inclined to reversible denaturation, different from the irreversible denaturation of β-Glucosidase as the crude cellulase was incubated statically in the alkali solution at pH9.00 and （25 ±1 ） ℃ for 30min.The residual enzyme activity value of three enzyme groups were respectively remained 58.8% of CMCase,56.6% of CBH and 5.7% of β-Glucosidase,thus the relative ratio between CMCase or CBH and β- Glucosidase reached 10.3 or 9.9. Alkali treatment improved greatly, the cellulase selectivity and produced the glucosidase-poor cellulase to hydrolyze selectively cellulose into cellooligosaccharides containing mainly cellobiose and little cellotriose.The product yield of cellooligosaccharide could reach 6.？3% when 10g/L paper powder solution was hydrolyzed at the enzyme loading of 0.1% （v/v）alkali treated cellulase for 24h. The oligosaccharides content accounted for 78.2% of the total degraded saccharides which increased by 53.6%, compared with the enzymatic hydrolysate with crude cellulase.

关 键 词：纤维素酶系 里氏木霉 酶选择性失活 定向酶水解 纤维低聚糖 

分 类 号：Q814.1[生物学—生物工程]