Comparative Removal of Bentazon by Ganoderma lucidum in Liquid and Solid State Cultures

Bentazon removal by Ganoderma lucidum cultured in liquid and solid state conditions was compared in this work. In solid state cultures, the fungus produced both ligninolytic enzymes, namely laccase and Mn peroxidase. In liquid cultures, the main ligninolytic enzyme produced was laccase. In both types of cultures bentazon improved the production of laccase without significant alteration in the production of Mn peroxidase. In solid state cultures, where high levels of both laccase and Mn peroxidase activities were found, the fungus was more resistant to the action of the herbicide (50 mM in solid state cultures against 20 mM in liquid cultures) and more efficient in removing bentazon (90% removal against 55% in liquid cultures after 10 days of cultivation). Furthermore, the solid state culture filtrates were more efficient in the in vitro degradation of bentazon than the liquid culture filtrates. These observations suggest that both enzymes, laccase and Mn peroxidase, are involved in bentazon degradation. The results further suggest that solid state cultures of Ganoderma lucidum could be useful in strategies designed to reduce environmental contamination by bentazon.