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 Bacillus subtilis expansin (BsEXLX1) onto cellulose films using a quartz crystal microbalance with dissipation. Cellobiose and xylose at low concentrations enhanced BsEXLX1 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 BsEXLX1 adsorption was found. Contact angle measurements and atomic force microscopy of cellulose upon BsEXLX1 adsorption in the presence of sugars showed that both hydrophilicity and roughness increased with BsEXLX1 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.

中文翻译：

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糖对膨胀酶在纤维素上实时吸附的影响。

生物预处理是一种破坏顽固性木质纤维素结构的安全且环保的方法。当与催化（半纤维素）分解成糖的纤维素酶混合使用时，弹性蛋白和类似弹性蛋白的蛋白可用于打开纤维素结构并显示出显着的协同作用。但是，在糖产品存在下，expandin的吸附行为尚不清楚。在这项工作中，我们使用耗散的石英晶体微量天平，监测了各种糖类对枯草芽孢杆菌扩展酶（BsEXLX1）实时吸附到纤维素膜上的影响。低浓度的纤维二糖和木糖会增强BsEXLX1的吸附，而高浓度的则会破坏吸附。随着浓度的增加，阿拉伯糖和甘露糖持续抑制expanin的吸附。葡萄糖和半乳糖对BsEXLX1的吸附没有明显影响。在糖存在下吸附BsEXLX1时，纤维素的接触角测量和原子力显微镜检查显示，随着BsEXLX1处理，亲水性和粗糙度均增加。这些结果使我们能够调节和控制弹性蛋白的吸附，并为生物精炼厂中木质纤维素的酶水解过程中有效使用弹性蛋白提供了见识。