Two bacterial strains, N-21 and N-22, which were isolated from natural oil-producing wells at Kurokawa, Niigata Prefecture, Japan, were identified as Pseudomonas cepacia by using the phylogenetic analysis based on the 16SrDNA sequences. Both strains were gram negative rods capable of decomposing naphthalene. The degradation rates were 2.24 × 10-5 M/h in both strains. The main metabolite was cis-1,2-dihydro-1,2-naphthalenediol. Salicylaldehyde, salicylic acid, gentistic acid and catechol were also identified. These metabolites were less mutagenic than naphthalene itself in the Ames test using the S. typhimurium TA100 strain. The mutagenicity of naphthalene also decreased by the two bacterial strains.
