Adsorption and mechanism of cellulase enzymes onto lignin isolated from corn stover pretreated with liquid hot water.
Adsorption and mechanism of cellulase enzymes onto lignin isolated from corn stover pretreated with liquid hot water.
复制标题
液态热水预处理的玉米秸秆木质素对纤维素酶的吸附及机理
DOI：
10.1186/s13068-016-0531-0
复制
发表时间：
2016
影响因子：
6.3
通讯作者：
Zhao J
中科院分区：
文献类型：
--
作者：
Lu X;Zheng X;Li X;Zhao J
背景在木质纤维素底物的生物转化中，纤维素酶在木质素上的吸附行为对纤维素的酶解有负面影响，降低了酶解过程中葡萄糖的产量，从而降低了发酵产率和有用产物的产量。了解木质素与纤维素酶之间的相互作用，对于优化纤维素酶混合物的组成、基因工程合成高效纤维素酶、降低生物转化成本具有重要意义。在液态热水预处理过程中，大部分木质素没有被去除，而且木质素在固体基质中的性质也发生了变化。为了了解纤维素酶和木质素之间的相互作用，本研究探讨了从玉米秸秆中获得的木质素的特性的变化，以及纤维素酶吸附到木质素上的行为，在不同的严重程度LHW预处理.ResultsLHW预处理去除大部分半纤维素和部分木质素的玉米秸秆，以及提高玉米秸秆的酶消化率。LHW预处理后，木质素分子量明显增加，但多分散性降低，且呈负值。木质素的疏水性和官能团也发生了变化。LHW预处理后玉米秸秆木质素对青霉纤维素酶的吸附增强，且随预处理强度的增加而增加。在不同的木质素样品和纤维素酶混合物组分中，甚至在不同的纤维二糖水解酶（CBH）、内切β-1，4-葡聚糖酶（EGs）中，观察到不同的吸附行为。木质素引起的酶活性降低最大的是CBH，其次是木聚糖酶，然后是EG和β-葡萄糖苷酶（BGL）。吸附行为对不同生物质底物的后续酶解产生不同的影响。疏水和静电相互作用可能是影响木质素与纤维素酶吸附行为差异的重要因素。结论LHW预处理改变了玉米秸秆中剩余木质素的性质，从而影响木质素对纤维素酶的吸附行为。对P.静电作用是影响EG和木聚糖酶在木质素上吸附的主要因素，而疏水性影响CBH和BGL在木质素上的吸附。
BackgroundIn the bioconversion of lignocellulosic substrates, the adsorption behavior of cellulase onto lignin has a negative effect on enzymatic hydrolysis of cellulose, decreasing glucose production during enzymatic hydrolysis, thus decreasing the yield of fermentation and the production of useful products. Understanding the interaction between lignin and cellulase is necessary to optimize the components of cellulase mixture, genetically engineer high-efficiency cellulase, and reduce cost of bioconversion. Most lignin is not removed during liquid hot water (LHW) pretreatment, and the characteristics of lignin in solid substrate are also changed. To understand the interactions between cellulase and lignin, this study investigated the change in the characteristics of lignin obtained from corn stover, as well as the behavior of cellulase adsorption onto lignin, under various severities of LHW pretreatment.ResultsLHW pretreatment removed most hemicellulose and some lignin in corn stover, as well as improved enzymatic digestibility of corn stover. After LHW pretreatment, the molecular weight of lignin obviously increased, whereas its polydispersity decreased and became more negative. The hydrophobicity and functional groups in lignin also changed. Adsorption of cellulase fromPenicillium oxalicumonto lignin isolated from corn stover was enhanced after LHW pretreatment, and increased under increasing pretreatment severity. Different adsorption behaviors were observed in different lignin samples and components of cellulase mixtures, even in different cellobiohydrolases (CBHs), endo-beta-1, 4-glucanases (EGs). The greatest reduction in enzyme activity caused by lignin was observed in CBH, followed by that in xylanase and then in EG and β-Glucosidase (BGL). The adsorption behavior exerted different effects on subsequent enzymatic hydrolysis of various biomass substrates. Hydrophobic and electrostatic interactions may be important factors affecting different adsorption behaviors between lignin and cellulase.ConclusionsLHW pretreatment changed the characteristics of the remaining lignin in corn stover, thus affected the adsorption behavior of lignin toward cellulase. For different protein components in cellulase solution fromP. oxalicum, electrostatic action was a main factor influencing the adsorption of EG and xylanase onto lignin in corn stover, while hydrophobicity affected the adsorption of CBH and BGL onto lignin.