Zhang Peiqian, Ma Yuanyuan, Cui Mei, Wang Jieying, Huang Renliang, Su Rongxin, Qi Wei, He Zhimin, Thielemans Wim
State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P.R. China.
Sustainable Materials Lab, Department of Chemical Engineering, KU Leuven, Campus Kulak Kortrijk, Etienne Sabbelaan 53, 8500 Kortrijk, Belgium.
Biomacromolecules. 2020 May 11;21(5):1776-1784. doi: 10.1021/acs.biomac.9b01694. Epub 2020 Feb 11.
Biological pretreatment is a safe and environmentally friendly method for disrupting recalcitrant lignocellulose structures. Expansin and expansin-like proteins are used to open up the cellulose structure and display significant synergism when mixed with cellulases that catalyze the breakdown of (hemi)cellulose into sugars. However, the adsorption behavior of expansin in the presence of sugar products is yet unknown. In this work, we monitored the effects of various sugars on the real-time adsorption of expansin (EXLX1) onto cellulose films using a quartz crystal microbalance with dissipation. Cellobiose and xylose at low concentrations enhanced EXLX1 adsorption, whereas they disrupted adsorption at higher concentrations. Arabinose and mannose continuously inhibited expansin adsorption with increasing concentration. No obvious influence of glucose and galactose on EXLX1 adsorption was found. Contact angle measurements and atomic force microscopy of cellulose upon EXLX1 adsorption in the presence of sugars showed that both hydrophilicity and roughness increased with EXLX1 treatment. These results give us the ability to modulate and control expansin adsorption and provide insights into effective expansin use during enzymatic hydrolysis of lignocellulose in biorefineries.
生物预处理是一种破坏顽固木质纤维素结构的安全且环保的方法。膨胀素和类膨胀素蛋白用于打开纤维素结构，并且在与催化（半）纤维素分解为糖的纤维素酶混合时表现出显著的协同作用。然而，在糖产物存在的情况下膨胀素的吸附行为尚不清楚。在这项工作中，我们使用具有耗散功能的石英晶体微天平监测了各种糖对膨胀素（EXLX1）在纤维素膜上实时吸附的影响。低浓度的纤维二糖和木糖增强了EXLX1的吸附，而在较高浓度时它们会破坏吸附。阿拉伯糖和甘露糖随着浓度增加持续抑制膨胀素吸附。未发现葡萄糖和半乳糖对EXLX1吸附有明显影响。在糖存在的情况下，对EXLX1吸附后的纤维素进行接触角测量和原子力显微镜观察表明，经EXLX1处理后亲水性和粗糙度均增加。这些结果使我们能够调节和控制膨胀素的吸附，并为生物精炼厂中木质纤维素酶水解过程中有效使用膨胀素提供见解。
