Physiology of exolaccase production by Thelephora terrestris

Thelephora terrestris, an ectomycorrhizal hymenomycete, produces extracellular laccase when grown in minimal liquid medium. The enzyme was characterized as a protein of 66 kDa. The optimal pH varied depending on the substrate utilized, being 5.0 for syringaldazine, 4.8 for guaiacol and 3.4 for ABTS. The K-m was 2.52 +/- 0.4 mu M for syringaldazine, 16 +/- 1.9 mu M for ABTS and 120.6 +/- 4.9 mu M for guaiacol. The secretion of laccase was biomass-dependent and independent of the glucose concentration in the medium. The addition of inducers did not increase laccase production which was dependent upon the ammonium phosphate concentration. (C) 1998 Published by Elsevier Science B.V.