Abstract

With proper design, immobilization can be useful tool to improve the stability of enzymes, and in certain cases even their activity, selectivity, productivity and economic viability. An immobilized β-glucosidase (BGL, EC 3.2.1.21) through matrix adsorption and cross-linked enzyme aggregate (ad-CLEA) technology is presented in this work. After adsorption and precipitation, BGL was immobilized to poly(glycidyl methacrylate-co-ethylenedimethacrylate) (P_GMA/EDMA) microparticles using glutaraldehyde as the cross-linker. Immobilized BGL exhibits lower apparent K_m but much higher V_max than that of the soluble enzyme, suggesting greater enzyme–substrate affinity and rapid velocity. Besides, ad-CLEA-BGL presents better thermostability retaining activity nearly 70% for 3 h and approximately 50% for 5 h at 70 °C, high operational reusability remaining more than 90% activity after nine uses and excellent storage stability holding about 95% activity after 45 days. Furthermore, the cellobiose is completely hydrolyzed within 1 h with ad-CLEA-BGL, which is significantly more efficient than soluble enzyme (about 4 h). Therefore, BGL was successfully immobilized on P_GMA/EDMA microparticles with an ad-CLEA technology and the immobilization greatly enhances the biochemical characteristics. This work indicates promising application for ad-CLEA-BGL in utilizing agricultural remnants, bio-converting cellobiose to fermentable reducing sugar and ethanol production.

Graphic abstract

中文翻译：

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通过吸附和交联酶聚集体增强 β-葡萄糖苷酶的生化特性，用于快速纤维二糖水解。

摘要

通过适当的设计，固定化可以成为提高酶稳定性的有用工具，在某些情况下甚至可以提高它们的活性、选择性、生产力和经济可行性。在这项工作中提出了通过基质吸附和交联酶聚集体 (ad-CLEA) 技术固定化的β-葡萄糖苷酶 (BGL, EC 3.2.1.21)。在吸附和沉淀后，使用戊二醛作为交联剂将BGL 固定到聚（甲基丙烯酸缩水甘油酯-共聚-二甲基丙烯酸乙二酯）（P _GMA/EDMA）微粒上。固定的 BGL 表现出较低的表观K _m但更高的V _max与可溶性酶相比，表明酶-底物亲和力更高，速度更快。此外，ad-CLEA-BGL 表现出更好的热稳定性，在 70°C 下保持 3 小时近 70% 和约 50% 约 50%，高操作可重用性在 9 次使用后仍保持超过 90% 的活性，以及​​优异的储存稳定性保持约 95% 45 天后的活动。此外，纤维二糖在 1 小时内被 ad-CLEA-BGL 完全水解，这比可溶性酶（约 4 小时）更有效。因此，BGL 成功地固定在P _{GMA/EDMA 上}具有ad-CLEA技术和固定化的微粒大大增强了生化特性。这项工作表明 ad-CLEA-BGL 在利用农业残余物、将纤维二糖生物转化为可发酵的还原糖和乙醇生产方面的应用前景广阔。

图形摘要