不同材种木质素影响底物吸附纤维素酶的水解机制  

Effect Mechanism of Lignin Isolated from Diverse Types Woods on Cellulase

作　　者：蒋康杰 吴文娟[1] 黄丽菁 李家全 黎孔燕 Jiang Kangjie;Wu Wenjuan;Huang Lijing;Li Jiaquan;Li Kongyan(Jiangsu Key Laboratory of Pulp and Paper Science and Technology Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesNanjing Forestry University,Nanjing 210037)

机构地区：[1]南京林业大学江苏省林业资源高效加工利用协同创新中心江苏省制浆造纸科学与技术重点实验室,南京210037

出　　处：《林业科学》2024年第7期140-148,共9页Scientia Silvae Sinicae

基　　金：国家自然科学基金青年基金资助项目(32271797,31730106)。

摘　　要：[目的]以杨木、桉木和相思木木质素为原料,探究纤维素酶在不同材种木质素和模拟底物上的吸附行为,为木质纤维原料预处理技术选择和酶水解转化成本降低提供参考。[方法]采用二维核磁方法分析提取木质素的组成结构,应用旋涂法制备木质素和木质素/纤维素薄膜,并对酶吸附前后的表面形貌进行表征,利用耗散型石英晶体微天平(QCM-D)技术原位、实时探究不同材种木质素吸附纤维素酶影响底物酶水解的规律。[结果]杨木、桉木和相思木分离木质素纯度高,均为GS型木质素(杨木、桉木和相思木木质素S/G比分别为1.09、1.73和1.22),木质素结构单元之间的主要连接方式为β-O-4结构。原子力显微镜(AFM)观察显示,底物水解过程中纤维素酶可均匀分布在底物和木质素表面且结合紧密,酶水解后桉木木质素薄膜的粗糙度高于杨木和相思木。经QCM-D分析木质素吸附纤维素酶的能力大小为杨木<相思木<桉木。[结论]原料酶水解过程可分为吸附、快速水解、缓慢水解和水解平衡4个阶段。同结构单元类型木质素对纤维素酶表现出的吸附能力不同,较高S/G比的木质素与纤维素酶之间的非生产吸附越多,导致酶与纤维素之间吸附位点减少,达到最大转化率所需时间更长,水解程度较低。[Objective]In order to explore the effect of lignin on enzyme adsorption in substrate enzyme hydrolysis,using the proto lignin as material,isolated from different species of poplar,eucalyptus and acacia wood,and the adsorption behavior of cellulase on lignin films was studied by quartz crystal microbalance with dissipation(QCM-D)technology.[Method]The structures of isolated lignins were characterized by 2D NMR.The lignin/cellulose biosensor was prepared by spin coating method and characterized by the surface morphology before and after enzyme adsorption,and the QCM-D technology was used to explore the influence of lignin with different structural unit on cellulase adsorption in situ and in real time.[Result]Lignins from poplar,eucalyptus and acacia were GS lignin,and the main connection mode between structural units wasβ-O-4,and their S/G ratios were 1.09,1.73 and 1.22,respectively.After the injection of the cellulase,the cellulase was evenly distributed on the surface of the lignin film,and they were bound tightly.The roughness of the lignin film of eucalyptus was higher than that of poplar and acacia at the end of injection.By QCM-D analysis,the poplar lignin film had minimal capacity to adsorb cellulase while eucalyptus lignin largest capacity.[Conclusion]Different structural unit types in lignin structure also show different adsorption capacity to cellulase.The enzymatic hydrolysis process of composite film can be divided into four stages:adsorption,rapid hydrolysis,slow hydrolysis and hydrolysis equilibrium.Combined with the kinetic parameters of enzymatic hydrolysis,eucalyptus lignin with higher S/G ratio takes longer time to reach the maximum enzymatic hydrolysis conversion and lower hydrolysis degree.

关 键 词：木质素 酶水解 结构单元 酶吸附 石英晶体微天平 

分 类 号：S785[农业科学—林学]