Contribution of Lignin Peroxidase, Manganese Peroxidase, and Laccase in Lignite Degradation by Mixed White-Rot Fungi

The catalytic depolymerization of biological enzymes during biological liquefaction of coal is very important. In this study, the effects of medium types, lignite addition, and mixed culture on lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase (Lac) secreted by white-rot fungi are investigated. Fifteen strains of white-rot fungi are used for microbial liquefaction of the Zhaotong lignite in Yunnan. The results show that the activities of LiP, MnP, and Lac are highest in the Czapek-Dox medium (DOX), followed by the Sabouraud Maltose Broth (SMB) medium, and are almost zero in the Potato Dextrose Agar (PDA) medium. In the early stage of fungal growth, the medium contains sufficient nutrients, and lignite addition induces an inhibitory effect on extracellular enzyme secretion, whereas in the late growth stage characterized by nutrient deficiency, it exhibits an enhancing effect. For fungi pair combinations, if only single enzyme activity was considered, the positive synergistic effect of Lac in the mixed culture ofs.communeand SL203 would be the highest, with the synergistic coefficient of 233.33. While three enzymes were considered, the integrated effects of ZTW07 and SL203 are the highest, with Lac, MnP, and LiP producing synergistic coefficients of 158.795, 1.217, and 1.006, respectively. It can be seen that the mixed culture can greatly improve the enzyme activity of white rot fungi and is one of the effective methods to improve the liquefaction efficiency. [GRAPHICS] .