title: Identification of soil bacteria able to degrade phenanthrene bound to a hydrophobic sorbent in situ.
abstract: Efficient bioremediation of PAH-contaminated sites is limited by the hydrophobic character and poor bioavailability of pollutants. In this study, stable isotope probing (SIP) was implemented to track bacteria that can degrade PAHs adsorbed on hydrophobic sorbents. Temperate and tropical soils were incubated with (13)C-labeled phenanthrene, supplied by spiking or coated onto membranes. Phenanthrene mineralization was faster in microcosms with PAH-coated membranes than in microcosms containing spiked soil. Upon incubation with temperate soil, phenanthrene degraders found in the biofilms that formed on coated membranes were mainly identified as Sphingomonadaceae and Actinobacteria. In the tropical soil, uncultured Rhodocyclaceae dominated degraders bound to membranes. Accordingly, ring-hydroxylating dioxygenase sequences recovered from this soil matched PAH-specific dioxygenase genes recently found in Rhodocyclaceae. Hence, our SIP approach allowed the detection of novel degraders, mostly uncultured, which differ from those detected after soil spiking, but might play a key role in the bioremediation of PAH-polluted soils.
authors.affiliation: CEA, DSV/iRTSV, Chimie et Biologie des Métaux, 38054, Grenoble cedex 9, France.
authors.forename: Raïssa Kom
authors.initials: RK
authors.lastname: Regonne
authors.forename: Florence
authors.initials: F
authors.lastname: Martin
authors.forename: Augustin
authors.initials: A
authors.lastname: Mbawala
authors.forename: Martin Benoît
authors.initials: MB
authors.lastname: Ngassoum
authors.forename: Yves
authors.initials: Y
authors.lastname: Jouanneau
mesh_terms: D001419:Bacteria / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D001673:Biodegradation, Environmental; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D010616:Phenanthrenes / Q000032:analysis / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D010616:Phenanthrenes; D012987:Soil; D012989:Soil Pollutants; C031181:phenanthrene
keywords: 16S rRNA; Hydrophobic sorption; PAH bioavailability; Ring-hydroxylating dioxygenase; Stable isotope probing