从菌株对桉叶残渣的降解、纯酶与桉叶木质素吸附和降解以及底物和产物变化3个角度,比较研究了木霉LaTr01和灵芝TR6产真菌漆酶降解桉叶木质素的差异。研究结果表明,残渣木质素的降解程度与菌株产漆酶的能力紧密相关,菌株在以桉叶残渣为底物的固态发酵过程中,灵芝TR6产漆酶酶活较高,但木霉LaTr01具有表达量大、胞外分泌率高、产酶速度快等特点;两种纯化真菌漆酶在精制桉叶木质素上的吸附更贴近非均匀表面两阶段多层吸附,符合Sips吸附模型,灵芝TR6被桉叶木质素吸附量较多,酶解效果就更明显;底物光谱分析和产物GC-MS法检测表明,两种漆酶对木质素降解后底物的官能团在种类上没有变化,数量上有一定的差异,降解途径都是侧链氧化去甲基化和芳香环骨架断裂。两真菌漆酶降解桉叶木质素的差异性主要体现分子结构导致的与底物易接近性,从而进一步导致降解酶解率、产物种类和数量的差异。

The Eucalyptus leaves lignin degradation by Trichoderma spp.LaTr01 and Ganoderma lucidum TR6 from three aspects the degradation of Eucalyptus leaves,the adsorption and degradation of pure enzyme and Eucalyptus lignin,and the changes of substrate and product.The results prove that the degradation degree of residual lignin was closely related to the laccase producing ability.In the process of solid-state fermentation with Eucalyptus leaves residue as substrate,the laccase activity of TR6 was higher,LaTr01 showed the characteristics of high expression,high excretion rate and rapid enzyme production.The adsorption of two kinds of purified laccase on purified Eucalyptus lignin was close to the Uniform Surface Two-Step Adsorption Model,which conformed to Sips adsorption model adsorption capacity of TR6 was higher and the effect was more obvious.Spectroscopic analysis of the substrate and detection of the product by GC-MS showed that there was no difference in the number of functional groups in the substrates of the two kinds of laccase,the degradation pathway of both the side chain oxidative demethylation and the aromatic ring skeleton breakage.The differences of the degradation of Eucalyptus leaves lignin by two kinds of fungal laccase mainly showed that the molecular structure of laccase led to the accessibility of the substrate,which further led to the enzymatic hydrolysis rate the type and quantity of products.