1971. The metabolism ofp-fluorobenzoic acid by a Pselrdonionas sp. Can. J. Microbial. 17: 1015-1023.A species of Pselido~nonas previously used to study the degradation of p-fluorophenylacetic acid was used to investigate the degradation of p-fluorobenzoic acid. During growth on the latter substrate all organic fluorine was released into the culture medium as fluoride. Several metabolic intermediates were isolated from the culture medium of resting cells. The major compounds have been identified as 4-fluorocatechol, p-acetylacrylic acid, (+)-4-carboxymethyl-4-fluorobut-2-enolide, (-)-4-carboxymethylbut-2-enolide, and 0-ketoadipic acid. A small quantity of a compound tentatively identified as p-fluoroacrylic acid was also isolated. On the basis of these findings, together with respiratory studies on pfluorobenzoic acid grown cells with various substrates, two metabolic pathways are proposed which involve elimination of fluorine at either of two alternative stages in the breakdown ofp-fluorobenzoic acid.

A number of molds, streptomycetes, and bacteria, obtained from culture collections and by enrichment techniques, were tested for their ability to degrade rutin. The molds, particularly Aspergillus fiavus and A. niger, appeared to be more active than either the streptomycetes or bacteria. The aspergilli when grown on either rutin or quercetin produced extracellular enzymes that degraded both rutin and quercetin but not quercitrin. Rutinose, protocatechuic acid, phloroglucinol carboxylic acid, and a phloroglucmo! carboxylic acid – protocatechuic acid ester were identified by paper chromatography as the products.

A strain of Pseudomanas isolated from soil with cinnamic acid as a sole carbon source was found to be simultaneously adapted to the utilization of cinnamic acid and phenylpropionic acid. During growth on either of these compounds, o-hydroxyphenylpropionic acid and 2,3-dihydroxyphenylpropionic acid were produced in the culture medium. The organism, when grown on either cinnamic acid or phenylpropionic acid, was adapted to the utilization of m-hydroxyphenylpropionic acid and 2,3-dihydroxyphenylpropionic acid, but not to the utilization of o-hydroxyphenylpropionic acid. According to the principle of sequential induction introduced by Stanier, the initial steps in the metabolism of cinnamic acid appear to involve the intermediates phenylpropionic acid, m-hydroxyphenylpropionic acid, and 2,3-dihydroxyphenylpropionic acid.

A strain of Arthrobacter catabolizes cyclohexanecarboxylic acid by a pathway involving aromatization of the ring before its cleavage. The pathway includes the following intermediates: trans-4-hydroxycyclohexanecarboxylic acid, 4-ketocyclohexanecarboxylic acid, p-hydroxybenzoic acid, protocatechuic acid, and β-ketoadipic acid. The oxidation of 4-hydroxycyclohexanecarboxylic acid by cell extracts specifically requires NAD+ and results in the production of 4-ketocyclohexanecarboxylic acid. The latter compound is oxidized in the presence of a suitable electron acceptor, such as oxygen, methylene blue, or 2,6-dichlorophenolindophenol, to p-hydroxybenzoic acid.

The metabolism of cyclohexanecarboxylic acid by a bacterium, designated PRL W19, follows a pathway involving beta-oxidation of coenzyme A intermediates analogous to the classical oxidation of fatty acids. The organism appears to have the property for the constitutive metabolism of caproic acid, and cell extracts contain high levels of the enzymes required for the functioning of the fatty acid cycle. However, the metabolism of cyclohexanecarboxylic acid requires induction by growth or incubation with an appropriate substrate. Extracts of induced cells contain several enzyme activities which are synthesized in response to the induction process. These enzymes include cyclohexanecarboxyl-CoA synthetase, cyclohexanecarboxyl-CoA dehydrogenase, 1-cyclohexenecarboxyl-CoA hydratase, and trans-2-hydroxycyclohexanecarboxyl-CoA dehydrogenase. A characteristics feature of this organism is that it becomes induced for the metabolism of benzoate and catechol during growth on cyclohexanecarboxylic acid, but benzoate does not appear to be an obligatory intermediate in the metabolism of cyclohexanecarboxylic acid.