College of Food Science, Southwest University, Chongqing 400715, China.
College of Food Science, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Speciality Food Co-Built by Sichuan and Chongqing, Chongqing 400715, China.
Int J Biol Macromol. 2022 Nov 1;220:1231-1240. doi: 10.1016/j.ijbiomac.2022.08.170. Epub 2022 Aug 29.
The catalytic activity of Candida antarctica lipase B (CALB) immobilized on modified cellulose nanocrystals (CNC) with different hydrophobicity was investigated using experimental and theoretical approaches. Firstly, the modified CNC were characterized by multi-spectroscopic methods, water contact angle, scanning electron microscopy and thermogravimetric analysis. Moderately hydrophobic CNC were found to be an optimal support for CALB immobilization. Secondly, model systems contained a CALB molecule and different numbers of modified CNC molecules (CALB@3CNC-C16, CALB@10CNC-C16 and CALB@15CNC-C16) were prepared for molecular dynamics (MD) simulation. Root-mean-square fluctuation values (0.61-2.61 Å) of lid region were relatively high in CALB@10CNC-C16, indicating that modified CNC with moderate hydrophobicity favored forming a lid-open conformation of CALB. Finally, the esterification of oleic acid catalyzed by the immobilized CALB showed higher conversion (54.68 %) than free CALB (12.98 %). Insights into modified CNC with tunable properties provided by this study may be a potential support for improving the catalytic performance of lipases.
用实验和理论的方法研究了不同疏水性的改性纤维素纳米晶体（CNC）固定化南极假丝酵母脂肪酶 B（CALB）的催化活性。首先，用多种光谱方法、水接触角、扫描电子显微镜和热重分析对改性 CNC 进行了表征。发现中等疏水性的 CNC 是固定化 CALB 的最佳载体。其次，为分子动力学（MD）模拟制备了包含 CALB 分子和不同数量改性 CNC 分子的模型系统（CALB@3CNC-C16、CALB@10CNC-C16 和 CALB@15CNC-C16）。CALB@10CNC-C16 中盖区的均方根波动值（0.61-2.61 Å）相对较高，表明中等疏水性的改性 CNC 有利于 CALB 形成开盖构象。最后，固定化 CALB 催化油酸的酯化转化率（54.68%）高于游离 CALB（12.98%）。本研究中对可调性质的改性 CNC 的深入了解可能为提高脂肪酶的催化性能提供一种潜在的支持。
