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, 15^th and 21^st day 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 pH 4.0-7.0. 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.

Key words: Paraconiothyrium variabile GHJ-4, laccase, manganese peroxidase(MnP), lignin peroxidase(LiP), enzyme characterization