title: Catalysis of PAH biodegradation by humic acid shown in synchrotron infrared studies.
abstract: The role of humic acid (HA) in the biodegradation of toxic polycyclic aromatic hydrocarbons (PAHs) has been the subject of controversy, particularly in unsaturated environments. By utilizing an infrared spectromicroscope and a very bright, nondestructive synchrotron photon source, we monitored in situ and, over time, the influence of HA on the progression of degradation of pyrene (a model PAH) by a bacterial colony on a magnetite surface. Our results indicate that HA dramatically shortens the onset time for PAH biodegradation from 168 to 2 h. In the absence of HA, it takes the bacteria about 168 h to produce sufficient glycolipids to solubilize pyrene and make it bioavailable for biodegradation. These results will have large implications for the bioremediation of contaminated soils.
authors.affiliation: Center for Environmental Biotechnology and Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. hyholman@lbl.gov
authors.forename: Hoi-Ying N
authors.initials: HY
authors.lastname: Holman
authors.forename: Karl
authors.initials: K
authors.lastname: Nieman
authors.forename: Darwin L
authors.initials: DL
authors.lastname: Sorensen
authors.forename: Charles D
authors.initials: CD
authors.lastname: Miller
authors.forename: Michael C
authors.initials: MC
authors.lastname: Martin
authors.forename: Thomas
authors.initials: T
authors.lastname: Borch
authors.forename: Wayne R
authors.initials: WR
authors.lastname: Mckinney
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Sims
mesh_terms: D001419:Bacteria; D001673:Biodegradation, Environmental; D001682:Biological Availability; D002384:Catalysis; D006812:Humic Substances / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D011721:Pyrenes / Q000378:metabolism; D013055:Spectrophotometry, Infrared; D017356:Synchrotrons
chemical_list: D006812:Humic Substances; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; C030984:pyrene