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
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%。
译 名：
Selective denaturation of major enzymatic components in cellulase system by alkali treatment and its application
作 者：
XU Yong1,2,3,CAI Peng1,2,3,FAN Li1,2,3,HANG Qi1,YONG Qiang1,2,YU Shi-yuan1,2 (1. College of Chemical Engineering,Nanjing Forestry University,Nanjing 210037,China; 2. Key Laboratory of Forest Genetics & Biotechnology MED,Nanjing 210037,China; 3. Jiangsu Key Lab of Biomass-based Green Fuel & Chemicals,Nanjing 210037,China)
关键词：
cellulase system;Trichoderma reese;selective denaturation of enzyme;selective enzymatic hydrolysis;cellooligosaccharides
摘 要：
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. 73% 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.
