Enhancement of minor laccases production in the basidiomycete Marasmius quercophilus C30.

The white-rot fungus Marasmius quercophilus C30 is able to produce several laccases. The proportion of the enzymes produced depends on culture conditions. On malt medium, LAC1 was produced continuously over the 14 days of the cultivation period and was the only activity detectable. Copper increased total laccase activity by a factor 10 and induced the transient expression of one or more extra laccases in the culture medium. A combination of copper and p-hydroxybenzoic acid made it possible to extend the expression of induced laccase activities over the cultivation period and to reach a maximum activity 30 times higher than in non-induced culture. Extracellular laccases produced in this last condition were eluted as four peaks on an anion exchange column and were partially characterized.