Laccase production by Pycnoporus sanguineus under different culture conditions.

Pycnoporus sanguineus is a white-rot fungus that produces ligninolytic enzymes such as laccases. These enzymes can endure temperatures as high as 60 degrees C and are useful for pulp bleaching, dye decolorization and phenolic degradation.Laccase production by fungi depends not only on the carbon and nitrogen sources but also on the nitrogen concentration of the culture medium. In this work, we examined the effect of four carbon sources (maltose, glucose, fructose and sucrose) and four nitrogen sources (ammonium tartrate, sodium nitrate, asparagine and yeast extract) on the activity of laccase from Pycnoporus sanguineus. All carbon and nitrogen sources exhibited a strong influence on laccase activity, a sucrose-asparagine medium providing the best results (320 mU/ml). Moreover, using an asparagine concentration 5 times higher than the reference level increased laccase activity to 820 mU/ml. Higher asparagine concentrations, however, resulted in no further increase in activity.Consistent with previous results, the carbon and nitrogen sources, and the nitrogen concentration, had a strong impact on laccase activity, the optimum conditions depending on the particular fungus. The conditions of the culture medium had a marked effect on laccase activity, which increased up to 820 mU/ml.