Salicylate formation from naphthalene by Pseudomonas aeruginosa.

Recently, in various parts of Gujarat State, India, oil has been located. Attempts were therefore made to isolate hydrocarbon-utilizing microorganisms from soil samples in these regions. Most of the isolates obtained from oil-rich fields were identified as species of Pseudomonas. One of these isolates, identified as P. aeruginosa, was used for studies on its hydrocarbon-attacking ability and naphthalene metabolism. Salicylate was isolated as one of the products of metabolism. Factors affecting salicylate metabolism were studied. Isolation of the hydrocarbon-attacking organism from soil samples was carried out following the procedure of G. J. Jankowski and C. E. ZoBell (J. Bacteriol. 47:447, 1944). The isolate was grown in medium containing (per liter) KH2PO4, 1.5 g; NH4NO3, 1.5 g; MgSO4-7H2O, 0.2 g; CaCl2-2H2O, 0.02 g; FeSO4-7H20, 0.02 g; and 1 % of the respective hydrocarbon. Optimal conditions for diesel oil utilization and diesel oil tolerance were studied in inorganic salts medium (50 ml in a 250-ml conical flask) containing 1% diesel oil in a culture grown for 7 days at 30 C on a rotary shaker. Salicylate was isolated from the medium in which naphthalene was added as sole carbon source by the method of N. Walker and G. H. Wiltshire (J. Gen. Microbiol. 8:273, 1954) and estimated by the method described by P. Trinder (Biochem. J. 57:301, 1954). Catechol from naphthaleneand salicylate-grown cultures was isolated and determined by the method of N. Walker and G. H. Wiltshire (J. Gen. Microbiol. 8:273, 1954) and of C. S. Vaidyanathan and P. M. Nair (Anal. Biochem. 7:315, 1964), respectively. Salicylate hydroxylase was estimated by the method of 0. Hayashi and M. Katagiri (J. Biol. Chem. 240:3408, 3414, 1965). The isolation and chromatographic detection of pyruvate from naphthalene-, salicylate-, and catechol-grown cultures were carried out by the method of T. E. Friedmann (J. Biol. Chem. 147:415, 1943). Protein was estimated by the method of 0. H. Lowry et al. (J. Biol. Chem. 193:265, 1951). The isolated strain of P. aeruginosa utilized diesel oil, kerosene, paraffin, petroleum waste TABLE 1. Hydrocarbon utilization by Pseudomonas aeruginosa