Isolation of a thermostable laccase with DMAB and MBTH oxidative coupling activity from a mesophilic white rot fungus

Carpophores of mesophilic basidiomycetes were isolated from the Eastern Cape region of South Africa. These isolates were screened for manganese peroxidase and laccase with high temperature optima. This bio-prospecting has led to the discovery of a thermostable laccase, which exhibits an optimum temperature of 70 °C. The enzyme remains fully active after 9 h incubation at 60 °C. The laccase is also capable of catalyzing the oxidative coupling of 3-dimethylaminobenzoic acid and 3-methyl-2-benzothiazolinone hydrazone, which are characterized as manganese peroxidase specific substrates. The wide temperature range, thermostability, and potentially wider than usual substrate range, make this an excellent candidate enzyme for industrial application.