HOMOLOGOUS PLASMIDS FROM SOIL BACTERIA ENCODING D,L-HALIDOHYDROLASES

We isolated and characterized D,L-halidohydrolases from five different soil bacteria. Three of these bacterial strains bear plasmids with si zes of approximately 60 kb. Curing and mating experiments indicated th at these three plasmids pFL160, pFL170, and pFL190 encoded a dehalogen ase. Owing to their biochemical characterization, these halidohydrolas es were closely related among each other and to the DhlIV halidohydrol ase, encoded by plasmid pFL40 from Alcaligenes xylosoxidans ssp. denit rificans ABIV. Restriction enzyme patterns as well as DNA-hybridizatio n experiments with an internal fragment of dhlIV revealed a high degre e of homology among each of these four plasmids and their dehalogenase genes.