Production optimization and molecular structure characterization of a newly isolated novel laccase from Fusarium solani MAS2, an anthracene-degrading fungus

• Statistical optimization by RSM resulted in 38.9-fold increase laccase production by Fusarium solani MAS2.
• Characterization of laccase by oxidization of different phenolic substrates.
• Phylogenetic and molecular structural analysis indicated this laccase is different from other reported laccase.

To investigate the potential of laccase production from strain Fusarium solani MAS2, the response surface methodology (RSM) was employed, and the maximum laccase activity of 159.78 U ml−1 was obtained at 20 °C and pH 6.5 with 30 mg l−1 of initial concentration of anthracene as the sole carbon source. Characterization of this laccase showed the similar properties with other reported laccases; however, the molecular identification, including matrix assisted laser desorption ionization-time of flight-tandem mass spectrum (MALDI-TOF-MS/MS) and gene cloning, demonstrated that this laccase was different from those available laccases, and only shared high homology with a non-identified, hypothetical oxidase from genome-sequenced strain Nectria haematococca, which was further annotated to be laccase. Further analysis on its nucleotide and amino acid sequences showed three introns present without detectable N-terminal signal peptide, indicating that this laccase might be synthesized within the cells.