A Gram-negative bacterium, strain AL98, was isolated from foul water inside of a deteriorated car tire on a farmer's field in Münster, Germany. The strain was able to considerably disintegrate natural rubber (NR), either in the raw state as NR latex concentrate or in the vulcanized state as NR latex glove, as well as raw synthetic cis-1,4-polyisoprene (IR). Determination of carbon dioxide evolution and living cell number during batch cultivation with each of the materials as sole source of carbon, revealed mineralization of the rubber polymer during biomass increase. Surface investigation by scanning electron microscopy gave evidence for an adhesive growth behavior of the strain proceeding by colonizing the rubber surface, merging into the rubber and forming a biofilm prior to disintegration of the material. Schiff's reagent staining performed with NR latex gloves indicated production and accumulation of aldehyde groups during colonization. The solid glove substrate disappeared completely after a prolonged cultivation period as a result of continuous degradation. Taxonomic analyses of the strain, which were also based on similarity examination of the complete 16S rRNA gene, revealed classification of strain AL98 as a strain of Pseudomonas aeruginosa. This is the first report about the isolation of a Gram-negative bacterium exhibiting strong rubber decomposing properties.