A strain of Bacillus brevis isolated from a polluted section of the Mississippi River was shown to utilize 5-chloro-2-hydroxybenzoate (5-chlorosalicylate) as a sole source of carbon and energy. Enzymic analyses of cell-free extracts prepared from 5-chlorosalicylate-grown cells demonstrated that the initial step in the pathway involved cleavage of the aromatic ring between Cl and C2 by a specific 5-chlorosalicylate 1,2-dioxygenase. Loss of chloride from the growth substrate occurred after ring fission and was probably enzyme mediated. An intermediate chlorolactone apparently lost chloride by enzymatic hydrolysis with formation of maleylpyruvate. Maleylpyruvate was further degraded by both glutathione-dependent and glutathione-independent mechanisms, with these reactions being identical to the terminal reactions of the gentisate pathway. It was suggested that this novel 5-chlorosalicylate pathway may have evolved by recruitment of enzymes from an ancestral gentisate pathway.

A biotransformation procedure has been developed to prepare intermediates for the synthesis of 3-hydroxyphenylacetylene (3-HPA), a high-value specialty chemical used in the manufacture of acetyleneterminated resins. Pseudomonas putida F39/D containing toluene dioxygenase was used to oxidize a series of substituted benzenes to their respective cis-2,3-dihydroxydihydrobenzene(cis-dihydrodiol) derivatives which in turn could be converted to 3-HPA via a metaphenol intermediate obtained by acid-catalyzed dehydration. The eis-dihydrodiols derived from the oxidation of phenylacetylene, styrene, acetophenone, and bromobenzene dehydrated to yield predominantly ortho-phenols. Three different phenyl-l,3-dioxolanes were oxidized by P. putida F39/D to three previously undescribed cis-dihydrodiols. Unlike mono-substituted cis-dihydrodiols, phenyl-l,3-dioxolane cis-dihydrodiols were dehydrated to form meta-phenols exclusively. The dehydration products, 3-hydroxyacetophenone and 3-hydroxybenzaldehyde, are suitable precursors for the chemical synthesis of 3-HPA.

Many bacteria biosynthesize 3,4-dihydroxyphenylacetate 2,3-dioxygenases for growth on aromatic acids, but gram-negative organisms have been most extensively studied. A gram-positive strain containing 2,3-dioxygenase activity was identified as Arthrobacter strain Mn-1. The 2,3-dioxygenase from strain Mn-1 was purified to homogeneity by fast protein liquid chromatography with a Mono Q anion-exchange column. Rabbit polyclonal antidioxygenase antibodies were prepared. Ouchterlony double-diffusion and Western blotting (immunoblotting) protocols were used to probe the distribution of the Mn-1 dioxygenase antigen in soil bacteria. Fourteen 2,3-dioxygenase-containing BaciUus and Pseudomonas strains did not contain immunologically cross-reactive proteins. Six of eight Arthrobacter strains contained 2,3-dioxygenase activity, and all of them produced cross-reactive proteins. The data presented here suggest that a unique type of dioxygenase is geographically widespread but is taxonomically confined to Arthrobacter soil bacteria.

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