Cell surface hydrophobicity test. A modified assay of microbial adhesion to hydrocarbons was utilized to determine changes in cell surface hydrophobicity during growth in SWF liquid medium with naphthalene as a substrate.Hexadecane (0.5 ml) and washed cells (2 ml) were vortexed in a test tube. After equilibration, the loss in absorbance of the aqueous phase relative to that of the initial cell suspension was measured, and hydrophobicity was estimated by calculating the percentage of cells adhering to hexadecane. Reported results are means of duplicate measurements.Analysis of naphthalene polar intermediates. The concentration of hydroxylated aromatic metabolites from naphthalene degradation was determined by an adaptation of the method outlined by Box, which uses the Folin-Ciocalteu reagent. A standard curve was prepared with sodium salicylate, and the concentration of metabolic intermediates was estimated as salicylate equivalents in milligrams per milliliter.