Enzyme activities of two recombinant heme-including peroxidases TvDyP1 and TvVP2 identified from the secretome of Trametes versicolor S Amara, T Perrot, D Navarro, A Deroy, A Benkhelfallah, A Chalak, … Applied and Environmental Microbiology, AEM. 02826-17

ABSTRACT

Trametes versicolor is a wood inhabiting Agaricomycete known for its ability to cause strong white rot decay on hardwood and for its high tolerance toward phenolic compounds. The goal of the present work was to give insights on the molecular biology and biochemistry of heme-including class-II and dye-decolorizing peroxidases secreted from this fungus. Proteomic analysis of the secretome of T. versicolor BRFM1218 grown on oak wood revealed a set of 200 secreted proteins among which were a dye-decolorizing peroxidase TvDyP1 and a versatile peroxidase TvVP2. Both peroxidases were heterologously produced in E. coli, and were biochemically characterized and tested for their capacity to oxidize complex substrates. Both peroxidases were found to be active against several substrates in acidic conditions, and TvDyP1 was very stable in a relatively large range of pH (pH 2.0 to 6.0) while TvVP2 was more stable at pH 5.0-6.0 only. Thermostability of both enzymes was also tested and TvDyP1 was globally found to be more stable than TvVP2. After 180 min of incubation at T°C ranging from 30°C to 50°C, activities of TvVP2 drastically decreased retaining 10% to 30% of the its initial activity. In the same conditions, TvDyP1 retained 20% to 80% of enzyme activity. The two proteins were catalytically characterized and TvVP2 was shown to accept a wider range of reducing substrates than TvDyP1. Furthermore, both enzymes were found to be active against two flavonoids, quercetin and catechin, found in oak wood, TvVP2 displaying a more rapid oxidation of the two compounds. They were tested for their potential interest in dye decolourization of five industrial dyes and TvVP2 presented a wider oxidation and decolourization capacity towards the dye substrates than TvDyP1.

IMPORTANCE Trametes versicolor is a wood inhabiting Agaricomycete known for its ability to cause strong white rot decay on hardwood and for its high tolerance toward phenolic compounds. Among white-rot fungi, the basidiomycete T. versicolor has been extensively studied for its efficiency to degrade wood, and specifically lignin, thanks to an extracellular oxidative enzymatic system. The corresponding oxidative system was previously studied in several works for classical lignin and manganese peroxidases, and in this study, two new components of the oxidative system of T. versicolor, one dye-decoloririzing peroxidase and one versatile peroxidase were biochemically characterized in depth and compare to other fungal peroxidases.