Plant oil was found to stimulate the formation of biomass in Pleurotus ostreatus, P. ostreatus from Florida and P. cornucopiae. The highest increase of the delipidized dry substance was found in P. ostreatus. The supernatant after submerged fermentation contained active emulsifiers. Fruiting bodies and mycelium of P. ostreatus did not contain cholesterol. Cholesterol added to homogenates of the fruiting bodies was degraded in a temperature-dependent manner. Degradation of cholesterol in the fermentation medium was slower.