Recyclable Soluble-Insoluble Upper Critical Solution Temperature-type Poly(methacrylamide-co-acrylic acid)-Cellulase Biocatalyst for Hydrolysis of Cellulose into Glucose
Recyclable Soluble-Insoluble Upper Critical Solution Temperature-type Poly(methacrylamide-co-acrylic acid)-Cellulase Biocatalyst for Hydrolysis of Cellulose into Glucose
复制标题
可回收的可溶-不溶上临界溶液温度型聚(甲基丙烯酰胺-丙烯酸)-纤维素酶生物催化剂用于纤维素水解成葡萄糖
DOI：
10.1021/acssuschemeng.8b00769
复制
发表时间：
2018-06-01
影响因子：
8.4
通讯作者：
Ni, Liang
中科院分区：
文献类型：
--
作者：
Han, Juan;Wan, Jing;Ni, Liang
如何提高固定化纤维素酶对不溶性纤维素的接近性，并从剩余的不溶性底物中回收固定化酶是纤维素高效水解成葡萄糖的一个挑战。为了解决上述问题，本文将纤维素酶固定化在聚甲基丙烯酰胺-共丙烯酸（PMAAc）上，开发出一种临界温度为16℃的可逆溶/不溶型生物催化剂。所制备的PMAAc-纤维素酶的临界温度为19℃，其pH、温度、储存和操作稳定性均较自由催化剂有显著提高。即使经过10个周期，其原始活性仍保持在82.4%左右。通过调节β -g的添加量，将含有内切-1,4-葡聚糖酶（EG）、纤维素生物水解酶（CBH）和β -葡萄糖苷酶（β -g）的纤维素酶体系以最佳比例共固定在PMAAc上，可以获得更高的水解效率。结果表明，纤维素酶与β -葡萄糖苷酶以2.5:1 （w/w）的最佳比例共固定化对纤维素的水解效果良好，在50℃（>UCST）条件下水解24 h，葡萄糖的产率可达89.1%，比PMAAc纤维素酶、游离纤维素酶和β -葡萄糖苷酶分别提高58.4%和15.4%。共固定化的PMAAc纤维素酶和-葡萄糖苷酶在水解8个周期后仍保持61.48%的产率。这种新型的ucst型聚合物酶催化体系在纤维素生物精制中显示出巨大的潜力。
How to improve the accessibility of immobilized cellulase to insoluble cellulose and recover immobilized enzyme from remaining insoluble substrate is a challenge to the efficient hydrolysis of cellulose into glucose. The objective of this work is to solve the problems mentioned above by the immobilization of cellulase onto poly(methacrylamide-co-acrylic acid) (PMAAc), developing a reversibly soluble-insoluble biocatalyst with upper critical solution temperature (UCST) of 16 degrees C. The as-prepared PMAAc-cellulase with a new UCST of 19 degrees C exhibited significantly improved pH, temperature, storage, and operation stabilities compared with that of free catalyst, and about 82.4% of its original activity was retained even after ten cycles. Cellulase systems containing endo-beta-1,4-glucanase (EG), cellobiohydrolase (CBH), and beta-glucosidase (beta-G) are coimmobilized at an optimum ratio on PMAAc by adjusting the additive amount of beta-G, which can obtain higher hydrolysis efficiency. It was found that the coimmobilization of cellulase and beta-glucosidase at the optimum ratio of 2.5:1 (w/w) showed excellent performance for the hydrolysis of cellulose, and the yield of glucose was up to 89.1% at 50 degrees C (>UCST) after 24 h, which was 58.4% and 15.4% higher than that of PMAAc cellulase and free cellulase and beta-glucosidase, respectively. The coimmobilized PMAAc cellulase and beta-glucosidase still retained 61.48% of its original productivity after eight cycles of hydrolysis. This novel UCST-type polymer enzyme catalytic system displays great potential in cellulose biorefining.