THE BACTERIAL DISSIMILATION OF NAPHTHALENE

Abstract

Data are presented indicating that the major pathway for the oxidation of naphthalene by a strain of Pseudomonas occurs via salicylic acid, which is further oxidized through catechol to beta-ketoadipic acid. On the basis of growth, simultaneous adaptation, and cell-free extract expts., the following compounds are regarded as unlikely intermediates in naphthalene dissimilation: 1,4-naphthoquinone, alpha-naphthol, beta-naphthol, 1,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,5-di-hydroxynaphthalene, phenol, trans-ortho-hydroxycinnamic acid, and phthalic acid. Evidence was found that a 2nd pathway of naphthalene oxidation produces 1,2-naphthoquinone. L,2-Dihy-droxynaphthalene is converted non-enzymatically to 1,2-naphthoquinone. The 1,2-naphthoquinone is not metabolized further and is responsible for the characteristic brown to reddish orange color of the culture medium. Omission of FeCl2 and MgSO4 from the basal medium prevents formation of salicylic acid but does not interfere with the production of 1,2-naphthoquinone.