Effects of Heavy Metals on Biodegradation of Fluorene by a Sphingobacterium sp. Strain (KM-02) Isolated from Polycyclic Aromatic Hydrocarbon-Contaminated Mine Soil

摘要

The present study investigated fluorene biodegradation by Sphingobacterium sp. KM-02 in the presence of heavy metals. A fluorene-degrading strain of Sphingobacterium was isolated from polycyclic aromatic hydrocarbon-contaminated soil near a mine-impacted area in Korea. When Sphingobacterium sp. KM-02 was grown in a medium with fluorene as the sole carbon source, it removed 78.4% of this compound within 120h. Identification of the metabolic intermediates (9-fluorenone, 4-hydroxy-9-fluorenone, and 8-hydroxy-3,4-benzocoumarin) were also performed. Composting experiments under laboratory conditions indicated that this microbe also removed fluorene from contaminated soil. In particular, treatment of microcosm soil with strain KM-02 for 20 days resulted in a 65.6% reduction of fluorene concentration. Experiments of effects of heavy metals on fluorene removal by strain KM-02 showed that 10mg/L cadmium, copper, zinc, and lead, reduced growth and fluorene degradation by this microbe. Cadmium and copper had strong effects at 10mg/L, although zinc and lead had relatively slight inhibitory effect at concentrations of 10 and 100mg/L. Arsenic had no effect on the growth or fluorene degradation, even at 100mg/L.