Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, People's Republic of China.
Colloids Surf B Biointerfaces. 2012 Jan 1;89:203-10. doi: 10.1016/j.colsurfb.2011.09.019. Epub 2011 Sep 17.
Adsorption of cellulase on substrates is a key step for enzymatic hydrolysis of lignocellulose. Addition of surface active additives affects the interaction between cellulase and substrates and has been proven to enhance enzymatic hydrolysis of lignocellulose by many studies. However, the mechanism of poly(ethylene glycol) effect is not yet clear. In this study, enzymatic activity and the adsorption of cellulase on different substrates with different addition sequence of PEG 4000 were investigated. The crystallinity index of substrates incubated by PEG 4000 was also measured by FTIR and XRD. Except for reduction of unproductive binding of cellulase on lignin which was reported by some literatures, current results confirmed a crucial function of PEG 4000 which prevented cellulase deactivation on cellulose rather than lignin through significant difference in adsorption capacity and enzymatic activity of cellulase with different PEG 4000 addition sequence. This conclusion rationally explained PEG 4000 had positive effect on pure cellulose without lignin as well as on lignocellulosic biomass. In addition, PEG 4000 was also found to be contributed to promote the removal of amorphous cellulose. These conclusions are helpful to understand the effect of surface active additives and optimize the enzymatic hydrolysis process.
纤维素酶在底物上的吸附是木质纤维素酶解的关键步骤。表面活性剂添加剂的添加会影响纤维素酶与底物之间的相互作用，许多研究已经证明它可以增强木质纤维素的酶解。然而，聚乙二醇（PEG）的作用机制尚不清楚。在本研究中，研究了不同添加顺序的 PEG 4000 对纤维素酶在不同底物上的吸附和酶活性的影响。还通过傅里叶变换红外光谱（FTIR）和 X 射线衍射（XRD）测量了添加 PEG 4000 后底物的结晶度指数。除了一些文献报道的降低纤维素酶与木质素的非生产性结合外，目前的结果还证实了 PEG 4000 的一个重要功能，即通过纤维素酶吸附能力和酶活性的显著差异，防止纤维素酶在纤维素上失活，而不是在木质素上失活。这一结论合理地解释了 PEG 4000 对不含木质素的纯纤维素以及木质纤维素生物质具有积极的影响。此外，还发现 PEG 4000 有助于促进无定形纤维素的去除。这些结论有助于理解表面活性剂添加剂的作用，并优化酶解过程。
