title: Anthracene biodegradation and surface activity by an iron-stimulated Pseudomonas sp.
abstract: Iron may enhance polycyclic aromatic hydrocarbons (PAHs) degradation directly by increasing the activity of the enzymes involved in the aerobic biodegradation pathways for hydrocarbons, and indirectly by increasing the PAHs bioavailability due to the stimulation of biosurfactant production. In the present work, the PAH anthracene was used in order to study the effect of different forms and concentrations of iron on its biodegradation and surfactant production by Pseudomonas spp. isolates from a 14-years old petrochemical sludge landfarm site. Among the iron forms, iron nitrate was chosen based on its high solubility and effect on the increase in the growth of the isolate. Iron concentration of 0.1mM was selected as the limit between deficiency and toxicity for isolates growth and anthracene degradation. After 48 days Pseudomonas citronellolis isolate 222A degraded 72% of anthracene related to iron stimulation and surface tension decrease, indicating surfactant production. Pseudomonas aeruginosa isolate 332C was iron-stimulated but did not reduce surface tension while P. aeruginosa isolate 312A exhibited a noniron and surfactant dependence to degrade 72% of anthracene. Isolate 222A showed a direct dependence on iron to stimulate surfactant activity, which probably increased anthracene bioavailability. To our knowledge, this is the first report about the iron effect on anthracene degradation and surfactant production by a Pseudomonas sp. Based on the iron requirement and surfactant activity, the Pseudomonas isolates may be useful for bioremediation of PAHs.
authors.affiliation: Department of Soil Science, Faculty of Agronomy, Federal University of Rio Grande do Sul, 7712 Bento Gonçalves Ave, 91540-000 Porto Alegre, RS, Brazil.
authors.forename: Eder C
authors.initials: EC
authors.lastname: Santos
authors.forename: Rodrigo J S
authors.initials: RJ
authors.lastname: Jacques
authors.forename: Fátima M
authors.initials: FM
authors.lastname: Bento
authors.forename: Maria do Carmo R
authors.initials: Mdo C
authors.lastname: Peralba
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Selbach
authors.forename: Enilson L S
authors.initials: EL
authors.lastname: Sá
authors.forename: Flávio A O
authors.initials: FA
authors.lastname: Camargo
mesh_terms: D000873:Anthracenes / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D011549:Pseudomonas / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism
chemical_list: D000873:Anthracenes; D012989:Soil Pollutants; D007501:Iron; C034020:anthracene