Degradation of fluoranthene by a newly isolated strain of Herbaspirillum chlorophenolicum from activated sludge

Abstract

A fluoranthene-degrading bacterial strain FA1 was isolated from activated sludge and identified as Herbaspirillum chlorophenolicum, a newfound bacterial species that can grow well on fluoranthene as sole carbon and energy source. The kinetic characteristic of strain FA1 was tested in the aqueous model system (AMS) and the effects of nonionic surfactants on fluoranthene biodegradation in the AMS were then investigated. Tween 80 exhibited the best solubilization capacity for fluoranthene among three surfactants and its bioavailability decreased with an increase in its concentration and its degradation kinetics fit well with the first-order of power index model. The biotransformation of fluoranthene was greatly improved by Tween 80, and 58.5% fluoranthene degradation was obtained as Tween 80 was 100 mg/l. However, the bioavailability of fluoranthene decreased gradually with the increase of Tween 80 concentration. Bioremediation tests for fluoranthene in soil-water system were designed further to examine the degrading ability of strain FA1 with the presence of indigenous flora or not. The measurements showed that in the presence of indigenous flora, the optimum 30-day fluoranthene degradation in soil-water system reached 77.4%. Evidently, strain FA1 seems both efficient and high-effective and deserves further exploration on the enhanced bioremediation technologies for the treatment of fluoranthene-polluted soil.