Biodegradation of fluoranthene by soil fungi.

A selection of 39 strains of micromycetes known as good degraders of polychlorinated aromatic compounds, mostly isolated from soil and belonging to various taxonomic groups, have been investigated for fluoranthene degradation. Toxicity assays, first evaluated on solid medium MEA, have not shown any toxicity of fluoranthene (1-100 mg.L-1) towards fungi. Whereas, consumption assays on a solid synthetic medium showed a toxicity at 100 mg.L-1. The degradation of fluoranthene (10 mg.L-1) was then investigated in a liquid synthetic medium for 4 days and evaluated by HPLC. Among the 39 strains tested, 18 degraded fluoranthene at 60% or more. Zygomycetes appeared to be the most efficient group (mean degradation: 90%). Among 18 performant strains, 10 had not yet been reported in the literature: Sporormiella australis, Cryptococcus albidus, Cicinobolus cesatii, Pestalotia palmarum, beauveria alba, Aspergillus terreus. Cunninghamella blakesleeana, C. echinulata, Mortierella ramanniana and Rhizopus arrhizus. Fluoranthene adsorption on fungi was very low for the strains which degraded well fluoranthene (mean adsorption: 4%). Whereas, some strains adsorbed it much more such as Colletotrichum dematium (47%) and Penicillium italicum (43%).