Acceleration of tributyltin chloride (TBT) degradation in liquid cultures of the filamentous fungus Cunninghamella elegans

In this study, we have examined the effects of synthetic medium ingredients and culture incubation conditions on growth and tributyltin chloride (TBT) degradation activity of the fungus Cunninghamella elegans. The best efficiency of TBT conversion to less toxic derivatives: dibutyltin and monobutyltin was noticed on media which contained glucose, NH4Cl, K2HPO4 and MgSO4. Next, the constructed M3 medium (with the above components) ensured vigorous growth of C. elegans and allowed the reduction of 80% of the initial TBT content (10 mg l−1), after 3 d of biodegradation. The further acceleration of the biocide utilization by C. elegans was achieved by additional oxygen supply (pO2 ⩾ 20%) to the growing fungus (89% after 2 d of incubation in the BioFlo II bioreactor). The efficient xenobiotic biodegradation was related to the intensity of fungal growth. The obtained results suggest a cometabolic nature of TBT utilization by C. elegans.