CATALYTIC BEHAVIOR AND DETOXIFYING ABILITY OF A LACCASE FROM THE FUNGAL STRAIN CERRENA UNICOLOR

The kinetics and stability of a laccase isolated and purified from the fungal strain Cerrena unicolor were studied. The enzyme was produced in a great yield without inducers. Kinetic parameters were determined by using 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) as s ubstrate. At high ABTS concentrations (> 10 mM) a substrate inhibition phenomenon appeared and an inhibition constant K-i of 24 mM was deter mined. The pH-and temperature-profiles as well as the sensitivity of t he enzyme to several deactivation agents were almost similar to those observed with laccase from different origins. Freezing-thawing treatme nt, high temperature, acidic pH (< 3.0) and acetonitrile strongly affe cted laccase activity. The laccase showed a good ability to oxidize di fferent phenolic substances; a significant enhancing effect was showed by ABTS acting as co-substrate. These results seem to suggest that th is new laccase preparation may be suitable for environmental purposes. (C) 1998 Elsevier Science B.V.