Characteristics and function of a low-molecular-weight compound with reductive activity from Phanerochaete chrysosporium in lignin biodegradation

A novel reductive compound with molecular weight of about 1000 Da, named Pc reducer, was purified from the liquid culture of a white-rot basidiomycete Phanerochaete chrysosporium. It was likely to have an alkene-ester structure according to Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectra. Pc reducer reduced the hydroxyl radical HO and the stable nitroxide radical under certain conditions. It inhibited the repolymerization of the products from the oxidation of phenolic lignin-model compounds by reducing certain intermediate radicals. The activity of manganese peroxidases was promoted by Pc reducer at certain concentrations. Pc reducer could also weaken the repolymerization of fragments from the oxidation of Na-lignosulfonate by lignin peroxidases and manganese peroxidases. It has potential ability to improve the ligninolytic efficiency of peroxidases in P. chrysosporium.