Effect of the herbicides bentazon and diuron on the production of ligninolytic enzymes by Ganoderma lucidum

The effect of the herbicides bentazon and diuron on growth and production of ligninolytic enzymes by the white-rot fungus Ganoderma lucidum, cultured in glucose liquid media, was evaluated. G. lucidum was resistant to the herbicides. The degree of resistance, however, was not the same for both compounds; the upper limits were 20 mM for bentazon, but only 80 μM for diuron. Furthermore, strong improvement of the laccase activity associated with growth reduction was observed during the first 48 h after the addition of the herbicides. Two laccase isoforms (lac 1 and lac 2) were found in the non-induced cultures. The herbicides acted as inducers of lac 2 and repressors of lac 1. Analysis of the residual herbicides showed that G. lucidum was able to remove both bentazon and diuron and, as with other white-rot fungi, it can be considered to be potentially useful in the development of methods aiming to reduce contamination by herbicides.