title: Dynamics of suspended and attached aerobic toluene degraders in small-scale flow-through sediment systems under growth and starvation conditions.
abstract: The microbially mediated reactions, that are responsible for field-scale natural attenuation of organic pollutants, are governed by the concurrent presence of a degrading microbial community, suitable energy and carbon sources, electron acceptors, as well as nutrients. The temporal lack of one of these essential components for microbial activity, arising from transient environmental conditions, might potentially impair in situ biodegradation. This study presents results of small scale flow-through experiments aimed at ascertaining the effects of substrate-starvation periods on the aerobic degradation of toluene by Pseudomonas putida F1. During the course of the experiments, concentrations of attached and mobile bacteria, as well as toluene and oxygen were monitored. Results from a fitted reactive-transport model, along with the observed profiles, show the ability of attached cells to survive substrate-starvation periods of up to four months and suggest a highly dynamic exchange between attached and mobile cells under growth conditions and negligible cell detachment under substrate-starvation conditions. Upon reinstatement of toluene, it was readily degraded without a significant lag period, even after a starvation period of 130 days. Our experimental and modeling results strongly suggest that aerobic biodegradation of BTEX-hydrocarbons at contaminated field sites is not hampered by intermittent starvation periods of up to four months.
authors.affiliation: †University of Tübingen, Center for Applied Geoscience, Hölderlinstrasse, 12, 72074 Tübingen, Germany.|‡now at: University of Waterloo, Department of Earth and Environmental Sciences, 200 University Ave. W, Waterloo, Ontario Canada N2L 3G1.
authors.forename: Adrian
authors.initials: A
authors.lastname: Mellage
authors.affiliation: †University of Tübingen, Center for Applied Geoscience, Hölderlinstrasse, 12, 72074 Tübingen, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Eckert
authors.affiliation: §Helmholtz Zentrum München, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Grösbacher
authors.affiliation: §Helmholtz Zentrum München, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany.
authors.forename: Ayse Z
authors.initials: AZ
authors.lastname: Inan
authors.affiliation: †University of Tübingen, Center for Applied Geoscience, Hölderlinstrasse, 12, 72074 Tübingen, Germany.
authors.forename: Olaf A
authors.initials: OA
authors.lastname: Cirpka
authors.affiliation: §Helmholtz Zentrum München, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Griebler
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000332:Aerobiosis; D001422:Bacterial Adhesion; D001673:Biodegradation, Environmental; D003198:Computer Simulation; D019015:Geologic Sediments / Q000382:microbiology*; D006838:Hydrocarbons / Q000378:metabolism; D016958:Pseudomonas putida / Q000254:growth & development* / Q000378:metabolism*; D014050:Toluene / Q000378:metabolism*
chemical_list: D006838:Hydrocarbons; D014050:Toluene; D000255:Adenosine Triphosphate