Some characteristics of a phenol-oxidizing Pseudomonas.

In a previous communication, Sheets et al. (1954) have shown that three phenol-resistant organisms, a sporeforming rod, a coccus and a short rod, belonging to the genera Bacillus, Micrococcus and Pseudomonas respectively, were isolated from a trickling filter, operated continuously at 54 C for the treatment of phenolic wastes. The Pseudomonas-like rod predominated over the other two types. A pure culture of this organism was capable of oxidizing phenol at a relatively high rate (Hamdy et al., 1954). Microorganisms that oxidize such aromatic compounds as phenol, m-cresol, and naphthalene have .been isolated by Kramer and Doetsch (1950), Czekalowski and Skarzynski (1948), and Gray and Thornton (1928). Physiological data on phenol-oxidizing bacteria have been reported by Egorova (1946), Evans (1947), Stanier (1948), and Sleeper and Stanier (1950). Kilby (1948) postulated the breakdown of phenol as: phenol -÷ catechol -o-benzoquinone -> 1,2,5, trihydroxybenzene -> 5 hydroxy o-benzoquinone -3-ketoadipic acid -* -succinate + acetate. Sleeper and Stanier (1950) reported that catechol is an intermediate in the oxidation of phenol by cells of Pseudomonas fluorescens. Stanier et al. (1950) confirmed that g-ketoadipic acid is an intermediate in the oxidation of catechol by P. fluorescens while hydroxyhydroquinone is highly improbable. An investigation was undertaken in this laboratory with the aim of securing more information concerning the characteristics of and the mechanism of phenol breakdown by an unidentified strain of Pseudomonas isolated from the trickling filter exposed to phenol liquor.