Journal of General Microbiology ( I 976), 96,209-2 I 3 Printed in Great Britain SHORT COMMUNICATIONS Oxidation of Aromatic Acids by a Facultative Thermophilic Bacillus sp.

Aerobic catabolism of benzoate and p-hydroxybenzoate is widely reported in several genera of bacteria. Oxidative breakdown of benzoate most frequently involves the formation of catechol prior to aromatic ring-fission whereasp-hydroxybenzoate is usually hydroxylated in the C-3 position to yield protocatechuate, Further conversion of these dihydroxylated products proceeds by either intradiol (ortho-fission) or extradiol (meta-fission) cleavage of the benzene nucleus (Dagley, 1971). An earlier report (Buswell & Twomey, 1974) indicated that gentisic acid was an inter-mediate in the degradation of benzoate by a thermophilic bacterium isolated from soil. We now describe the novel conversion of p-hydroxybenzoate to gentisate by a facultative thermophilic strain of Bacillus, and the subsequent induction, during growth on benzoate and p-hydroxybenzoate, of enzymes which catalyse gentisate dissimilation. METHODS Bacteria. The organism was isolated from coke-oven washings (Ravenscraig Steelworks Motherwell, Lanarkshire) by selective enrichment at 55 "C in a semi-defined basal medium which contained p-hydroxybenzoate as the major carbon and energy source. It is facul-tatively thermophilic with upper and lower temperature limits for growth of 62 "C and 30 "C, respectively. It is considered to be a Bacillus sp. because young cultures consisted of Gram-positive slender rods of different lengths and aged cultures contained oval endospores, located terminally or subterminally, which swell the vegetative cell. Media. The basal growth medium contained (g 1-l): K,HPO,, 0.5; NH,Cl, 1.0; MgSO,. 7H,O, 0.02; yeast extract (Oxoid), 0.1; aromatic growth substrate, 1.0; I ml trace element solution; adjusted to pH 7.2 with 2 M-NaOH. The trace element mixture consisted of (g 1-l)