星点设计优选苦参纤维素酶解提取工艺研究

目的 利用纤维素酶对苦参进行水解,以提高苦参有效成分的提取转移率、节省提取时间.方法 在单因素试验基础上,以HPLC测得的苦参碱、氧化苦参碱的提取转移率为指标,采用星点试验设计,对加酶量（X1）、酶解pH（X2）和酶解时间（X3）3个因素（每个因素设5个水平）进行考察,优选苦参最佳酶解条件,并且以水提取方法作为对比,对...     

β-聚糖酶的诱导合成Ⅱ:初始pH值与培养温度的影响

以绿色木霉 (Trichodermaviride)LH -0 11为产酶菌株 ,利用自制复合碳源 ,对初始pH值、培养温度等因素对 β 聚糖酶合成的影响进行了研究。结果表明 :以预处理玉米芯为碳源 (浓度 15 g/L) ,调节碳氮比为 6.4,初始 pH 4.8,15 0r/min摇瓶培养 ,前期( 3 2± 1)℃培养 2 4h ,后期 ( 2 8± 1)℃变温调控培养 72h ,纤维素酶活力和木聚糖酶活力分别达到了 3 .76U/mL和 13 .95U/mL。     

酶解法提取鸡血藤原儿茶酸的工艺研究

目的优化鸡血藤中原儿茶酸的提取工艺。方法在鸡血藤甲醇回流前,用果胶酶、纤维素酶分别处理,与未加酶组比较,得出最优酶。通过单因素实验,探讨最优酶的用量、时间、温度及酸碱度(pH)对原儿茶酸提取率的影响,并通过正交实验对其进行优化。结果果胶酶比纤维素酶的原儿茶酸提取率高,最优酶提取最佳条件为:加入pH 4.5果胶酶0.5%、50℃酶解1.5 h,70℃浸提2次,原儿茶酸提取率为2.88%。结论最佳条件下酶法能提高鸡血藤中原儿茶酸提取率。     

赤子爱胜蚓(Eisenia Foelide)纤维素酶的初步研究

将赤子爱胜蚓整体组织匀浆的抽提液,经Sephadex G-75凝胶过滤、DEAE-Sepharose CL-6B离子交换及在FPLC仪上用Mono Q柱分离,可以纯化到多种组分的纤维素酶,研究了它们的酶学性质,证明均为C_X酶。     

Purification of particles of subterranean clover red leaf virus using an industrial-grade cellulase

Particles of two isolates of subterranean clover red leaf virus were purified by a method in which infected plant tissue was digested with an industrial-grade cellulase, Celluclast 2.0 L type X. The yields of virus particles using this enzyme were comparable with those obtained using either of two laboratory-grade cellulases, Cellulase type 1 (Sigma) and Driselase. However, the specific infectivity or aphid transmissibility of the particles purified using Celluclast was 10-100 times greater than those of preparations obtained using laboratory-grade cellulases or no enzyme. The main advantage of using Celluclast is that at present in Australia its cost is only ca. 1% of laboratory-grade cellulases.     

桑黄菌发酵过程中酶活性的变化

目的 研究桑黄菌发酵过程中酶活性的变化及其和胞外多糖量的关系。方法 在发酵过程中测定原始菌株和变异菌株的羧甲基纤维素酶、滤纸酶、木质素过氧化物酶（LiP）、锰过氧化物酶（MnP）、漆酶（Lac）活性变化及培养基中胞外多糖量变化。结果 2菌株的羧甲基纤维素酶和滤纸酶的活性变化呈单峰曲线,分别在第4天和第6天达到峰值;原始菌株和变异菌株的LiP、锰过氧化物酶和漆酶活性的变化呈双峰曲线,且原始菌株和变异菌株LiP的酶促反应米氏常数（K_m）分别为25.96、27.07 μg/mL;MnP的K_m分别为13.28、13.49 mmol/mL;Lac的K_m分别为0.12、0.21 mmol/mL;培养基中多糖量前期快速下降,10 d后趋于稳定。结论 桑黄菌发酵时能产生较全面的分解木质素和纤维素的酶系统,原始菌株和变异菌株产生的LiP和MnP为同种酶,Lac为同功酶。桑黄菌胞外酶活性变化和培养基中胞外多糖量变化有一定关系。     

Insights into the oxidative degradation of cellulose by a copper metalloenzyme that exploits biomass components

The enzymatic degradation of recalcitrant plant biomass is one of the key industrial challenges of the 21st century. Accordingly, there is a continuing drive to discover new routes to promote polysaccharide degradation. Perhaps the most promising approach involves the application of "cellulase-enhancing factors," such as those from the glycoside hydrolase (CAZy) GH61 family. Here we show that GH61 enzymes are a unique family of copper-dependent oxidases. We demonstrate that copper is needed for GH61 maximal activity and that the formation of cellodextrin and oxidized cellodextrin products by GH61 is enhanced in the presence of small molecule redox-active cofactors such as ascorbate and gallate. By using electron paramagnetic resonance spectroscopy and single-crystal X-ray diffraction, the active site of GH61 is revealed to contain a type II copper and, uniquely, a methylated histidine in the copper's coordination sphere, thus providing an innovative paradigm in bioinorganic enzymatic catalysis.