Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Technology, Fuzhou University, Fuzhou 350116, China.
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China.
Int J Mol Sci. 2022 Mar 8;23(6):2917. doi: 10.3390/ijms23062917.
This study aimed to improve the stability and catalytic properties of Thermomyces lanuginosus lipase (TLL) adsorbed on a hydrophobic support. At the optimized conditions (pH 5 and 25 °C without any additions), the Sips isotherm model effectively fitted the equilibrium adsorption data, indicating a monolayer and the homogenous distribution of immobilized lipase molecules. To preserve the high specific activity of adsorbed lipase, the immobilized lipase (IL) with a moderate loading amount (approximately 40% surface coverage) was selected. Polyethylenimine (PEI) and chitosan (CS) were successfully applied as bridging units to in situ crosslink the immobilized lipase molecules in IL. At the low polymer concentration (0.5%, w/w) and with 1 h incubation, insignificant changes in average pore size were detected. Short-chain PEI and CS (MW ≤ 2 kDa) efficiently improved the lipase stability, i.e., the lipase loss decreased from 40% to <2%. Notably, CS performed much better than PEI in maintaining lipase activity. IL crosslinked with CS-2 kDa showed a two- to three-fold higher rate when hydrolyzing p-nitrophenyl butyrate and a two-fold increase in the catalytic efficiency in the esterification of hexanoic acid with butanol. These in situ crosslinking strategies offer good potential for modulating the catalytic properties of TLL for a specific reaction.
本研究旨在提高嗜热丝孢菌脂肪酶（TLL）在疏水载体上吸附的稳定性和催化性能。在优化条件（pH5 和 25°C，无任何添加）下，Sips 等温线模型有效地拟合了平衡吸附数据，表明固定化脂肪酶分子呈单层且均匀分布。为了保持吸附脂肪酶的高比活性，选择了中等载量（约 40%的表面覆盖率）的固定化脂肪酶（IL）。聚乙烯亚胺（PEI）和壳聚糖（CS）成功地用作桥联单元，原位交联 IL 中的固定化脂肪酶分子。在低聚合物浓度（0.5%，w/w）和 1 小时孵育下，平均孔径没有明显变化。短链 PEI 和 CS（MW≤2 kDa）有效地提高了脂肪酶的稳定性，即脂肪酶损失从 40%降低到<2%。值得注意的是，CS 在保持脂肪酶活性方面的性能优于 PEI。与 CS-2 kDa 交联的 IL 在水解对硝基苯丁酸时的速率提高了两到三倍，在己酸和丁醇的酯化反应中的催化效率提高了两倍。这些原位交联策略为调节 TLL 在特定反应中的催化性能提供了良好的潜力。
