【摘要】 【目的】研究木质素降解子囊菌Paraconiothyrium variabile GHJ-4分泌的漆酶（laccase）、锰过氧化物酶（MnP）和木质素过氧化物酶（LiP）3种木质素降解酶的酶活性变化规律及其酶学性质,为利用该菌株进行木质素降解酶的工业化生产和应用提供依据。【方法】分别以愈创木酚、2,6-二甲基苯酚和黎芦醇为底物测定laccase,MnP和LiP的酶活性,研究3种酶的最适反应温度和pH、温度和pH稳定性及金属离子对其活性的影响。【结果】GHJ-4菌株发酵18,15和21天后,分别获得laccase,MnP和LiP最高酶活为1 390.3,30.3和52.5 U·mL^-1。laccase的最适反应温度为55℃左右,最适反应pH为5.5左右,在55℃以下、pH 4.0⁷.0的范围内较为稳定;MnP的最适反应温度为60℃左右,最适反应pH为5.0左右,在55℃以下、pH 4.0⁹.0的范围内较为稳定;LiP的最适反应温度为40℃左右,最适反应pH为3.0左右,在40℃以下、pH 2.0⁴.0的范围内较为稳定。Mg²⁺,Zn²⁺,Cu²⁺,K⁺对laccase起促进作用,Na⁺和Zn²⁺对LiP起促进作用,Mn²⁺对MnP起激活作用,而Fe³⁺,Ca²⁺,Pb²⁺,Co²⁺,Al³⁺对3种酶均起抑制作用,其中尤以5 mmol·L^-1Fe³⁺对3种酶的抑制作用最强。【结论】温度、pH及金属离子对Paraconiothyrium variabile GHJ-4 3种木质素降解酶的酶学特性均有着不同程度的影响。更多还原

【Abstract】 【Objective】The production and enzymological characteristics of ligninolytic enzymes,including laccase,manganese peroxidase（MnP） and lignin peroxidase（LiP） produced by Paraconiothyrium variabile GHJ-4 were investigated.This study could provide theoretical data for commercial process and application of Paraconiothyrium variabile GHJ-4 ligninolytic enzymes.【Method 】Laccase,MnP and LiP activity were measured with guaiacol,2,6-Dimethylphenol and veratryl alcohol as substrate respectively.Effects of temperature,pH value and metal irons on three ligninolytic enzymes were assayed.【Result】Laccase,MnP and LiP activity reached the peak value of 1 390.3 U·mL^-1,30.3 U·mL^-1 and 52.5 U·mL^-1 respectively on the 18 th,15thand 21 stday during the fermentation.The optimum temperature and pH of laccase were 55 ℃ and 5.5 respectively,and the enzyme activity was stable under 55 ℃ and pH4.0-7.0.The optimum temperature and pH of MnP were 60 ℃ and 5.0 respectively,and the enzyme activity was stable under 55 ℃ and pH 4.0-9.0.The optimum temperature and pH of LiP were 40 ℃ and 3.0 respectively,and the enzyme activity was stable under 40 ℃ and pH 2.0-4.0.Laccase activity was enhanced by the metal ions Mg²⁺,Zn²⁺,Cu²⁺,K+,LiP activity was enhanced by Na+and Zn²⁺,and MnP activity was enhanced by Mn²⁺.Whereas three ligninolytic enzymes were inhibited by Fe³⁺,Ca²⁺,Pb²⁺,Co²⁺ and Al³⁺,especially the effect of Fe³⁺ was the strongest.【Conclusion】The effects of temperature,pH and metal ions on activities of ligninolytic enzymes from Paraconiothyrium variabile GHJ-4 were different.更多还原