title: Evaluation of the Galega-Rhizobium galegae system for the bioremediation of oil-contaminated soil.
abstract: The bioremediation potential of a nitrogen-fixing leguminous plant, Galega orientalis, and its microsymbiont Rhizobium galegae was evaluated in BTX (benzene, toluene, xylene)-contaminated soils in microcosm and mesocosm scale. To measure the intrinsic tolerance of the organisms to m-toluate, a model compound representing BTX, G. orientalis and R. galegae were cultivated under increasing concentrations of m-toluate alone and in association with Pseudomonas putida pWWO, a bacterial strain able to degrade toluene-derived compounds. The test plants and rhizobia remained viable in m-toluate concentrations as high as 3000 ppm. Plant growth was inhibited in concentrations higher than 500 ppm, but restituted when plants were transferred into m-toluate-free medium. Nodulation was blocked under the influence of m-toluate, but was restored after the plants were transferred into the non-contaminated media. In the mesocosm assay the Galega plants showed good growth, nodulation and nitrogen fixation, and developed a strong rhizosphere in soils contaminated with oil or spiked with 2000 ppm m-toluate. Thus, this legume system has good potential for use on oil-contaminated sites
authors.affiliation: Department of Applied Chemistry and Microbiology, PO Box 56, Viikki Biocenter, 00014 University of Helsinki, Helsinki, Finland. leena.suominen@helsinki.fi
authors.forename: L
authors.initials: L
authors.lastname: Suominen
authors.forename: M M
authors.initials: MM
authors.lastname: Jussila
authors.forename: K
authors.initials: K
authors.lastname: Mäkeläinen
authors.forename: M
authors.initials: M
authors.lastname: Romantschuk
authors.forename: K
authors.initials: K
authors.lastname: Lindström