RESEARCH ARTICLE Carbazole hydroxylation by the filamentous fungi

Abstract Nitrogen heterocyclic compounds, especially car-bazole, quinolone, and pyridine are common types of environ-mental pollutants. Carbazole has a toxic influence on living organisms, and the knowledge of its persistence and biocon-version in ecosystems is still not complete. There is an increas-ing interest in detoxification of hazardous xenobiotics by mi-croorganisms. In this study, the ability of three filamentous fungi of the Cunninghamella species to eliminate carbazole was evaluated. The Cunninghamella elegans IM 1785/21Gp and Cunninghamella echinulata IM 2611 strains efficiently removed carbazole. The IM 1785/21Gp and IM 2611 strains converted 93 and 82 % of the initial concentration of the xenobiotic (200 mg L−1) after 120 h incubation. 2-Hydroxycarbazole was for the first time identified as a carba-zole metabolite formed by the filamentous fungi of the Cunninghamella species. There was no increase in the toxicity of the postculture extracts toward Artemia franciscana. Moreover, we showed an influence of carbazole on the phos-pholipid composition of the cells of the tested filamentous fungi, which indicated its harmful effect on the fungal cell membrane. The most significant modification of phospholipid levels after the cultivation of filamentous fungi with the addi-tion of carbazole was showed for IM 1785/21Gp strain