Purification and biochemical characterization of laccase from Kuehneromyces mutabilis.

A novel laccase was successfully purified from the culture filtrate of Kuehneromyces mutabilis using a combination of ammonium sulfate precipitation and ion exchange chromatography. The purified enzyme, designated as Kmlac, has a molecular weight of approximately 70 kDa. Partial amino acid sequences of Kmlac, obtained via LC-MS/MS analysis, exhibited significant homology with those of laccases derived from other fungal species. The optimal temperature and pH for Kmlac activity were determined to be 60 °C and 4.0, respectively. Kmlac exhibited relatively stable activity at pH 4.0 and temperatures below 40 °C. Notably, Kmlac activity was enhanced in the presence of Co²⁺, Al³⁺, Ni²⁺ and Cu²⁺ ions at appropriate concentrations, while it was strongly inhibited by DTT, L-cysteine, and phenol. The enzyme demonstrated the ability to degrade various dyes over different time intervals during decolorization processes. The Km value for the ABTS substrate was determined to be 0.56 mM. Given these characteristics, the novel laccase from K. mutabilis holds significant potential for industrial applications.

Supplementary information: The online version contains supplementary material available at 10.1007/s13205-025-04512-1.