Pyrene degradation by two fungi in a freshwater sediment and evaluation offungal biomass by ergosterol content

Mucor racemosus var. sphaerosporus and Phialophora alba were investigated f or their abilities to degrade pyrene in a freshwater sediment, with or with out glucose supply as nutrient or carbon source, during 90 days. The ergost erol contents in sediment were quantified to estimate fungal biomass and to assess the correlation between fungal activity and biodegradation of pyren e. Results showed that, in an heterogeneous environment, these fungi presen ted different abilities to degrade pyrene. P. alba increased the degree of pyrene degradation by 9%, compared to the native micro-organisms, but a sup ply of glucose acted as an inhibitor to pyrene disappearance. M. racemosus var. sphaerosporus was not efficient at sediment bioremediation (with or wi thout glucose added), because it reduced the rate of pyrene degradation by the native microflora. In any case, there was no increase of ergosterol in boxes during bioremediation experiments. In our experimental conditions, er gosterol content could not be correlated to pyrene degradation.