Degradation of Ochratoxin A and B by the white rot fungus Pleurotus ostreatus

Degradation of ochratoxin A (OTA) and B (OTB) by three selected fungi during solid state fermentation of barley contaminated with ochratoxins was compared. In presence of the soil fungus Rhizopus japonicus and the white rot fungus Panerochaete chrysosporium more than 60 % of the mycotoxins remained stable, while in the white rot fungus Pleurotus ostreatus only 23 % of the initial OTA and 3 % of OTB were detected after a four weeks incubation period. Kinetic studies on mycotoxin degradation by PI ostreatus demonstrated formation of ochratoxin α and presumably ochratoxin β as intermediate products, what indicates that hydrolysis is the first step in OTA and OTB degradation followed by further degradation of the intermediates.