title: Low effect of phenanthrene bioaccessibility on its biodegradation in diffusely contaminated soil.
abstract: This study focused on the role of bioaccessibility in the phenanthrene (PHE) biodegradation in diffusely contaminated soil, by combining chemical and microbiological approaches. First, we determined PHE dissipation rates and PHE sorption/desorption isotherms for two soils (PPY and Pv) presenting similar chronic PAH contamination, but different physico-chemical properties. Our results revealed that the PHE dissipation rate was significantly higher in the Pv soil compared to the PPY soil, while PHE sorption/desorption isotherms were similar. Interestingly, increases of PHE desorption and potentially of PHE bioaccessibility were observed for both soils when adding rhamnolipids (biosurfactants produced by Pseudomonas aeruginosa). Second, using13C-PHE incubated in the same soils, we analyzed the PHE degrading bacterial communities. The combination of stable isotope probing (DNA-SIP) and 16S rRNA gene pyrosequencing revealed that Betaproteobacteria were the main PHE degraders in the Pv soil, while a higher bacterial diversity (Alpha-, Beta-, Gammaproteobacteria and Actinobacteria) was involved in PHE degradation in the PPY soil. The amendment of biosurfactants commonly used in biostimulation methods (i.e. rhamnolipids) to the two soils clearly modified the PHE sorption/desorption isotherms, but had no significant impact on PHE degradation rates and PHE-degraders identity. These results demonstrated that increasing the bioaccessibility of PHE has a low impact on its degradation and on the functional populations involved in this degradation.
authors.affiliation: COBRA UMR CNRS 6014, Université de Rouen-Normandie, 55 rue saint Germain, 27000 Evreux, France; Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Université de Rouen, 76821 Mont Saint Aignan, France.
authors.forename: M
authors.initials: M
authors.lastname: Crampon
authors.affiliation: CNRS, LIEC UMR 7360, Faculté des Sciences et Technologies, BP70239, 54506 Vandoeuvre-lès-Nancy Cedex, France; Université de Lorraine, LIEC UMR 7360, Faculté des Sciences et Technologies, BP70239, 54506 Vandoeuvre-lès-Nancy Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Cébron
authors.affiliation: COBRA UMR CNRS 6014, Université de Rouen-Normandie, 55 rue saint Germain, 27000 Evreux, France.
authors.forename: F
authors.initials: F
authors.lastname: Portet-Koltalo
authors.affiliation: UMR 1138 INRA, Centre de Nancy, Biogéochimie des Ecosystèmes forestiers, Route d'Amance, 54280 Champenoux, France.
authors.forename: S
authors.initials: S
authors.lastname: Uroz
authors.affiliation: COBRA UMR CNRS 6014, Université de Rouen-Normandie, 55 rue saint Germain, 27000 Evreux, France.
authors.forename: F
authors.initials: F
authors.lastname: Le Derf
authors.affiliation: Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Université de Rouen, 76821 Mont Saint Aignan, France; Université de Lyon, France, CNRS, INRA, Ecole Nationale Vétérinaire de Lyon, Université Lyon 1, UMR 5557 Ecologie Microbienne, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France. Electronic address: josselin.bodilis@univ-rouen.fr.
authors.forename: J
authors.initials: J
authors.lastname: Bodilis
mesh_terms: D020562:Betaproteobacteria / Q000235:genetics; D001673:Biodegradation, Environmental; D020563:Gammaproteobacteria; D006017:Glycolipids; D010616:Phenanthrenes / Q000737:chemistry / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D006017:Glycolipids; D010616:Phenanthrenes; D012336:RNA, Ribosomal, 16S; D012987:Soil; D012989:Soil Pollutants; C418382:rhamnolipid; C031181:phenanthrene
keywords: Bioaccessibility; Biosurfactant; DNA-SIP; PAH; Phenanthrene biodegradation; Rhamnolipids; Rhodocyclaceae; Soil; Sorption isotherm