title: Motile Geobacter dechlorinators migrate into a model source zone of trichloroethene dense non-aqueous phase liquid: experimental evaluation and modeling.
abstract: Microbial migration towards a trichloroethene (TCE) dense non-aqueous phase liquid (DNAPL) could facilitate the bioaugmentation of TCE DNAPL source zones. This study characterized the motility of the Geobacter dechlorinators in a TCE to cis-dichloroethene dechlorinating KB-1(™) subculture. No chemotaxis towards or away from TCE was found using an agarose in-plug bridge method. A second experiment placed an inoculated aqueous layer on top of a sterile sand layer and showed that Geobacter migrated several centimeters in the sand layer in just 7days. A random motility coefficient for Geobacter in water of 0.24±0.02cm(2)·day(-1) was fitted. A third experiment used a diffusion-cell setup with a 5.5cm central sand layer separating a DNAPL from an aqueous top layer as a model source zone to examine the effect of random motility on TCE DNAPL dissolution. With top layer inoculation, Geobacter quickly colonized the sand layer, thereby enhancing the initial TCE DNAPL dissolution flux. After 19days, the DNAPL dissolution enhancement was only 24% lower than with an homogenous inoculation of the sand layer. A diffusion-motility model was developed to describe dechlorination and migration in the diffusion-cells. This model suggested that the fast colonization of the sand layer by Geobacter was due to the combination of random motility and growth on TCE.
authors.affiliation: Department of Earth and Environmental Sciences, Division of Soil and Water Management, KU Leuven (University of Leuven), Kasteelpark Arenberg 20, B-3001 Heverlee, Belgium. Electronic address: jo.philips@ugent.be.
authors.forename: Jo
authors.initials: J
authors.lastname: Philips
authors.affiliation: Department of Mathematics and Statistics, University of Massachusetts, Lederle Graduate Research Tower, Amherst MA 01003-9305, USA. Electronic address: alexeym@cns.umass.edu.
authors.forename: Alexey
authors.initials: A
authors.lastname: Miroshnikov
authors.affiliation: Department of Earth and Environmental Sciences, Division of Soil and Water Management, KU Leuven (University of Leuven), Kasteelpark Arenberg 20, B-3001 Heverlee, Belgium. Electronic address: pieterjan.haest@agt.be.
authors.forename: Pieter Jan
authors.initials: PJ
authors.lastname: Haest
authors.affiliation: Department of Earth and Environmental Sciences, Division of Soil and Water Management, KU Leuven (University of Leuven), Kasteelpark Arenberg 20, B-3001 Heverlee, Belgium. Electronic address: dirk.springael@ees.kuleuven.be.
authors.forename: Dirk
authors.initials: D
authors.lastname: Springael
authors.affiliation: Department of Earth and Environmental Sciences, Division of Soil and Water Management, KU Leuven (University of Leuven), Kasteelpark Arenberg 20, B-3001 Heverlee, Belgium. Electronic address: erik.smolders@ees.kuleuven.be.
authors.forename: Erik
authors.initials: E
authors.lastname: Smolders
mesh_terms: D001673:Biodegradation, Environmental; D002633:Chemotaxis; D004058:Diffusion; D045302:Geobacter / Q000502:physiology*; D054879:Halogenation; D008962:Models, Theoretical; D014241:Trichloroethylene / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D014241:Trichloroethylene
keywords: Bio-enhanced TCE DNAPL dissolution; Bioaugmentation; Geobacter; KB-1™ culture; Microbial migration; Random motility; Reductive dechlorination