Structure-Activity Relationships in Microbial Transformation of Phenols

Abstract

The second-order rate constants for the microbial transformation of a series of phenols were correlated with the physicochemical properties of the phenols. The compounds studied were phenol, p -methylphenol, p -chlorophenol, p -bromophenol, p -cyanophenol, p -nitrophenol, p -acetylphenol, and p -methoxyphenol. Phenol-grown cells of Pseudomonas putida U transformed these compounds. Microbial transformation rate constants ranged from (1.5 ± 0.99) × 10 −14 liter · organism −1 · h −1 for p -cyanophenol to (7.0 ± 1.3) × 10 −12 liter · organism −1 · h −1 for phenol. Linear regression analyses of rate constants and electronic, steric, and hydrophobic parameters showed that van der Waal's radii gave the best coefficient of determination ( r 2 = 0.956). Products identified by thin-layer chromatography and liquid chromatography indicated that the phenols were microbially oxidized to the corresponding catechols.