Characterization of a novel manganese peroxidase from white-rot fungus Echinodontium taxodii 2538, and its use for the degradation of lignin-related compounds

MnP from E. taxodii 2538 was able to degrade both nonphenolic and phenolic lignin model compounds, while Lac from the same fungus could degrade phenolic lignin model compounds only. Moreover in vitro, these two ligninolytic enzymes from E. taxodii 2538 degraded complicated lignin more efficiently when they acted in combination. [Display omitted] •A novel MnP (manganese peroxidase) from white rot fungus E. taxodii 2538 was reported for the first time.•The MnP was stable at its optimum pH and had strong tolerance in acidic environment.•The MnP could oxidize both phenolic and nonphenolic lignin units.•The MnP combined with laccase from E. taxodii 2538 degraded lignin more efficiently. A novel manganese peroxidase (MnP) was isolated and characterized in this study. The MnP was produced by a new selective linguini-degrading white-rot fungus Echinodontium taxodii 2538 (E. taxodii 2538) on natural lignocellulose medium of moso bamboo. The purified MnP had an estimated molecular mass of 53.4kDa, showing a single band on sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE), and composed of an amino acid sequence of GTTPSNGVVVP at N-terminal. The enzyme showed maximum activity when incubated at pH 3.5 or 55°C and could maintain a high enzymatic activity after 24h incubation under a broad range of pH (2.0–6.0) and temperature (below 45°C). The kinetic parameters revealed that the MnP had the highest affinity toward MnSO4 (Km values was 0.35μM) among all the substrates. Degradation of different types of lignin model compounds by MnP was investigated. It revealed that the MnP could oxidize both phenolic and nonphenolic lignin units. In addition, the MnP combined with laccase (Lac) from E. taxodii 2538 could degrade lignin more efficiently. In summary, this study provided a potential enzyme and a promising path for more efficient lignin modification.