Characterization of optimized production, purification and application of laccase from Ganoderma lucidum

We show for the first-time Ganoderma lucidum laccase enzyme production using medium containing 3% (v/v) ethanol, which enhanced the enzyme production up to 14.1 folds. A more than 400-folds increase could be achieved if grown in the presence of the novel lignocellulosic biomass tamarind shell plus ethanol (3%, v/v), CuSO4 (0.4 mM) and gallic acid (1 mM). A 38.3 kDa laccase enzyme was purified from the initial protein preparation with an overall yield of 32% using Sephadex G-100 and DEAE-cellulose column chromatography. The enzyme was identified through MALDI-TOF/TOF tandem mass spectrometry (MS/MS) as G. lucidum laccase-3. This enzyme exerted its optimal activity at a pH of 5 and a temperature of 55 °C with ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) as an ideal substrate. The catalytic efficiencies (kcat/Km) determined for ABTS and guaiacol were 11.5 × 105 and 3.9 × 105 s−1 M−1, respectively. The G. lucidum laccase decolorized various textile dyes and industrial textile dye effluent up to 90% and 97%, respectively.

► Laccase was produced under the optimized medium containing 3% (v/v) ethanol.
► Laccase production was enhanced 416 folds by the biomass tamarind shell.
► Purified laccase exhibits stability within a range of pH (4–7.5).
► Purified laccase exhibits stability within a range of temperature (30–60 °C).
► Laccase-mediated decolorization of different dyes without a redox mediator.