Tu Maobing, Zhang Xiao, Kurabi Arwa, Gilkes Neil, Mabee Warren, Saddler Jack
Department of Wood Science, Forest Sciences Centre, University of British Columbia, 2424 Main Mall, V6T 1Z4, Vancouver, BC, Canada.
Biotechnol Lett. 2006 Feb;28(3):151-6. doi: 10.1007/s10529-005-5328-3.
beta-Glucosidase is frequently used to supplement cellulase preparations for hydrolysis of cellulosic and lignocellulosic substrates in order to accelerate the conversion of cellobiose to glucose. Typically, commercial cellulase preparations are deficient in this enzyme and accumulation of cellobiose leads to product inhibition. This study evaluates the potential for recycling beta-glucosidase by immobilization on a methacrylamide polymer carrier, Eupergit C. The immobilized beta-glucosidase had improved stability at 65 degrees C, relative to the free enzyme, while the profile of activity versus pH was unchanged. Immobilization resulted in an increase in the apparent Km from 1.1 to 11 mM: and an increase in Vmax from 296 to 2430 micromol mg(-1) min(-1). The effect of immobilized beta-glucosidase on the hydrolysis of cellulosic and lignocellulosic substrates was comparable to that of the free enzyme when used at the same level of protein. Operational stability of the immobilized beta-glucosidase was demonstrated during six rounds of lignocellulose hydrolysis.
β-葡萄糖苷酶常用于补充纤维素酶制剂，以水解纤维素和木质纤维素底物，从而加速纤维二糖向葡萄糖的转化。通常，商业纤维素酶制剂中这种酶含量不足，纤维二糖的积累会导致产物抑制。本研究评估了通过固定在甲基丙烯酰胺聚合物载体Eupergit C上循环利用β-葡萄糖苷酶的潜力。相对于游离酶，固定化β-葡萄糖苷酶在65℃时稳定性有所提高，而活性与pH的关系曲线未变。固定化导致表观Km从1.1 mM增加到11 mM，Vmax从296 μmol mg⁻¹ min⁻¹增加到2430 μmol mg⁻¹ min⁻¹。当使用相同水平的蛋白质时，固定化β-葡萄糖苷酶对纤维素和木质纤维素底物水解的效果与游离酶相当。在六轮木质纤维素水解过程中证明了固定化β-葡萄糖苷酶的操作稳定性。
