Isolation, characterization and function of laccase from Trichoderma

Abstract

Of fourteen natural isolates of Trichoderma, no correlation was found between substrate weight loss and phenol oxidase (PO) activity in rice straw cultures. The highest PO producer from these laccase-positive strains was subjected to UV mutagenesis in order to select high and low PO activity mutants. There was no significant difference in substrate weight loss for mutant strains with six times higher and six times lower PO activity than the parent strain. Nor did the enzyme activity result in decreased growth inhibition by inhibitory phenolic compounds. PO enzyme from the parent Trichoderma and one of its high-PO-activity mutants was subsequently purified by ethanol precipitation from liquid cultures optimized by supplementation with copper sulphate and cycloheximide. Protein staining and activity staining of disc electrophoresis gels showed that only one PO enzyme of approximately 71000 Da was produced. The enzyme could be defined as a laccase (benzenediol: oxygen oxidoreductase E.C. 1.10.3.2) because it catalysed the oxidation of syringaldazine and p-phenylenediamine in the absence of hydrogen peroxide, and because it was inhibited by cetyltrimethylammonium bromide but not by cinnamic acid. No specific in-vivo function could be assigned to this enzyme.

Interspecific interactions with Trichoderma longibrachiatum induce Pleurotus ostreatus defence reactions based on the production of laccase isozymes

“…The production of laccases by Trichoderma sp. has been reported in some studies (Assavaning et al 1992;Hölker et al 1999). In sterilized white-button-mushroom composts, detectable levels of laccase activities were produced by T. harzianum, T. virens and T. longibrachiatum (Savoie et al 2001a, b).…”

Characterization of commercial cellulases and their use in the saccharification of a sugarcane bagasse sample pretreated with dilute sulfuric acid

“…is not a potential or large producer of phenoloxidases [34,38]. However, some researchers reported the ability of some strains to produce oxidative enzymes, especially laccases [3,14,18]. There are also papers reporting the production of laccase [25], manganese peroxidase [21], and lignin peroxidase [1] by Aspergillus sp.…”

Decolorization and Metabolism of Anthraquionone-Type Dye by Laccase of White-Rot Fungi Polyporus sp. S133

“…Laccase can be applied extensively in many fields, including waste detoxification and textile dye transformation due to their low substrate specificity (Couto and Herrera 2006). Although some fungal laccase have been characterized (Assavanig et al 1992;Thakker et al 1992;Baldrian 2006), little information is available concerning their substrate specificities towards dye decolorization. Large amounts of chemically different dyes are used for textile dyeing and a significant proportion of these dyes enter the environment as wastewater.…”