For the first time the production of an emulsifying agent during phthalic, 2,2'-diphenic and alpha-hydroxy-beta-naphthoic acids, phenanthrene, anthracene, fluorene, pyrene, fluoranthene, and chrysene degradation by white rot fungus Pleurotus ostreatus was found. The emulsifying activity of the cultivation medium after degradation of these compounds was assessed. Maximal activities were found in the presence of chrysene (48.4%) and alpha-hydroxy-beta-naphthoic acid (52.2%). Emulsifying activity inversely dependent on the water solubility of the compounds used. Versatile peroxidase was produced concurrently with the emulsifying agent.