Enzymes of naphthalene metabolism by Pseudomonas fluorescens 26K Strain

The ability of Pseudomonas fluorescens 26K strain to utilize naphthalene at concentrations up to 600 mg/liter as the sole source of carbon and energy in mineral liquid media was shown. Using HPLC, TLC, and mass-spectrometry, the intermediates of naphthalene transformation by this strain were identified as naphthalene cis-1,2-dihydrodiol, salicylaldehyde, salicylate, catechol, 2-hydroxymuconic semialdehyde, and 1-naphthol. Catechol 2,3-dioxygenase (a homotetramer with native molecular mass 125 kDa) and NAD+-dependent homohexameric naphthalene cis-1,2-dihydrodiol dehydrogenase with native molecular mass 160 kDa were purified from crude extract of the strain and characterized. NAD+-dependent homodimeric salicylaldehyde dehydrogenase with molecular mass 110 kDa was purified and characterized for the first time. Based on the data, a pathway of naphthalene degradation by P. fluorescens 26K is suggested.