BIOTRANSFORMATION OF HALOPHENOLS BY A THERMOPHILIC BACILLUS SP

The thermophilic Bacillus sp. A2 transformed various halophenols. 2-Ch lorophenol, 2-bromophenol, 3-bromophenol and 2-fluorophenol were trans formed under resting cell conditions at 60 degrees C to 3-chlorocatech ol, 3-bromocatechol, 4-bromocatechol and 3-fluorocatechol, respectivel y. The hydroxylation of 3-bromophenol occurred at the proximal and dis tal position relative to the halogen substituent. In complex medium th is strain completely transformed 2-chlorophenol and 2-bromophenol at c oncentrations up to 1 mM. Concomitantly, an accumulation of oxygen- an d temperature sensitive halocatechols was observed. 3-Chlorocatechol p ossesses a half-life of 11.5 h at 60 degrees C and is therefore readil y decomposed during incubation. The hydroxylating system was present i n phenol-grown cells but not in glucose-grown cells. The hydroxylase a ctivity could also be induced by 2-chlorophenol. The product, 3-chloro catechol, is not a substrate for the catechol 2,3-dioxygenase.