The report from the University of Illinois College of Medicine at Chicago covers three years of research under a Cooperative Agreement. A pure culture of Pseudomonas capacia strain AC1100, isolated from a chemostat enrichment culture experiment, is capable of growing on 2,4,5-T as its sole source of carbon and energy. Metabolic pathway studies indicate the activity of both constitutive and inducible enzymes. In laboratory experiments, soil contaminated with 2,4,5-T could be detoxified by AC100 treatment, with the titer of AC1100 rapidly falling to nearly undetectable levels after the 2,4,5-T was substantially degraded. Extensive homology observed between plasmids points to the role of plasmid genes in the evolution and spread of degradative characters against toxic chemical compounds. A 1.3 kilobase pair DNA repeated sequence was found in strain AC1100. The specificity of this sequence to AC1100 suggests that this unique sequence may be a useful genetic probe of strain AC1100 and other novel Pseudomonas strains which are under consideration for deliberate release to aquatic and terrestrial environments.