Fungal degradation of fluorene

A selection of 30 strains of micromycetes known as good degraders of polych lorinated aromatic compounds, mostly isolated from soil and belonging to va rious taxonomic groups, have been investigated to degrade fluorene. Toxicit y assays, first evaluated on solid media, have shown high growth inhibition at concentrations above 0.001 g l(-1) only towards 23% of strains. Degrada tion of fluorene (0.005 g l(-1)) was then investigated in liquid synthetic medium for 2 days and evaluated by HPLC. Among the 30 strains tested, 12 co uld be considered as best degraders because of a rate of degradation at 60% or over. 3 strains of Cunninghamella genus were very efficient (mean of de gradation: 96%) but different strains from Ascomycetes, Basidiomycetes and Deuteromycetes were also efficient. 11 strains are not yet reported in the literature: Aspergillus terreus, Bjerkandera adusta, Ceriporiopsis subvermi spora, Colletotrichum? dematium, Cryphonectria parasitica, Cunninghamella b lakesleeana, C. echinulata, Drechslera spicifera, Embellisia annulata, Rhiz octonia solani and Sporomiella australis. A metabolic approach with standar d compounds (9-fluorenol and 9-fluorenone) indicated the presence of these monooxygenated derivatives for most of the strains. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.