College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhunan Road, Nanjing 211816, Jiangsu, China.
School of Pharmaceutical Sciences, Nanjing Tech University, 30 Puzhunan Road, Nanjing 211816, Jiangsu, China.
Food Chem. 2019 Jun 1;282:101-108. doi: 10.1016/j.foodchem.2019.01.004. Epub 2019 Jan 6.
A one-step method to immobilize xylanase onto cellulosic material by fusion of expansin from Bacillus subtilis to xylanase LC9 without the requirement of prior purification of enzyme has been developed. Fusion enzyme EXLX-R2-XYN was specifically adsorbed onto corncob residue with high loading capacity due to bio-affinity adsorption of expansin onto cellulose. The immobilization yield was close to 100%, with a recovered activity of 82.4%. The immobilized EXLX-R2-XYN retained 45.3% of its activity after incubation at 70 °C for 3 h, whereas only 16.3% of the activity was left in free form under the same conditions. The conversion yield of XOS by using immobilized EXLX-R2-XYN reached up to 515 mg/g xylan from 2% corncob extracted xylan, which was higher than that of the free enzyme. The hydrolysis products were mainly xylobiose (57.5%) and xylotriose (38.4%), without undesirable xylose production. After five cycles of hydrolysis, more than 70% of conversion was obtained.
已经开发出一种将枯草芽孢杆菌扩张蛋白融合到木聚糖酶 LC9 上来固定木聚糖酶到纤维素材料上的一步法，而无需事先对酶进行纯化。由于扩张素对纤维素的生物亲和吸附，融合酶 EXLX-R2-XYN 能够特异性地吸附到玉米芯残余物上，具有高的负载量。固定化收率接近 100%，回收率为 82.4%。在 70°C 孵育 3 小时后，固定化 EXLX-R2-XYN 保留了其活性的 45.3%，而在相同条件下，游离酶的活性仅剩下 16.3%。使用固定化 EXLX-R2-XYN ，从 2%玉米芯提取的木聚糖中，XOS 的转化率最高可达 515mg/g 木聚糖，高于游离酶。水解产物主要为木二糖（57.5%）和木三糖（38.4%），没有产生不良的木糖。经过五次水解循环，转化率超过 70%。
