title: Optimization of high-molecular-weight polycyclic aromatic hydrocarbons' degradation in a two-liquid-phase bioreactor.
abstract: A microbial consortium degrading the high-molecular-weight polycyclic aromatic hydrocarbons (HMW PAHs) pyrene, chrysene, benzo[a]pyrene and perylene in a two-liquid-phase reactor was studied. The highest PAH-degrading activity was observed with silicone oil as the water-immiscible phase; 2,2,4,4,6,8, 8-heptamethylnonane, paraffin oil, hexadecane and corn oil were much less, or not efficient in improving PAH degradation by the consortium. Addition of surfactants (Triton X-100, Witconol SN70, Brij 35 and rhamnolipids) or Inipol EAP22 did not promote PAH biodegradation. Rhamnolipids had an inhibitory effect. Addition of salicylate, benzoate, 1-hydroxy-2-naphtoic acid or catechol did not increase the PAH-degrading activity of the consortium, but the addition of low-molecular-weight (LMW) PAHs such as naphthalene and phenanthrene did. In these conditions, the degradation rates were 27 mg l-1 d-1 for pyrene, 8.9 mg l-1 d-1 for chrysene, 1.8 mg l-1 d-1 for benzo[a]pyrene and 0.37 mg l-1 d-1 for perylene. Micro-organisms from the interface were slightly more effective in degrading PAHs than those from the aqueous phase.
authors.affiliation: Centre de microbiologie et biotechnologie, INRS-Institut Armand-Frappier, Université du Québec, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Marcoux
authors.forename: E
authors.initials: E
authors.lastname: Déziel
authors.forename: R
authors.initials: R
authors.lastname: Villemur
authors.forename: F
authors.initials: F
authors.lastname: Lépine
authors.forename: J G
authors.initials: JG
authors.lastname: Bisaillon
authors.forename: R
authors.initials: R
authors.lastname: Beaudet
mesh_terms: D001564:Benzo(a)pyrene / Q000378:metabolism; D019149:Bioreactors; D002911:Chrysenes / Q000378:metabolism; D008970:Molecular Weight; D010569:Perylene / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D011721:Pyrenes / Q000378:metabolism; D012828:Silicones
chemical_list: D002911:Chrysenes; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; D012828:Silicones; D001564:Benzo(a)pyrene; D010569:Perylene