[Role of cosubstrates in the microbiologic oxidation of xylene isomers by a culture of Pseudomonas aeruginosa].

Cosubstrates (additional substrates) produced different effect on transformation of isomeric xylenes of Pseudomonas aeruginosa 7. The cosubstrates manifested the highest stimulating effect on transformation of o-xylene, on which the culture did not grow, and p-xylene, in the presence of which only a weak growth was detected. The most effective cosubstrates were xylose and maltose which were actively oxidized by the culture but could not serve as carbon sources. One of mechanisms of the cosubstrate action is inhibition (or repression of synthesis) of the enzymes responsible for oxidation of toluic acids by the cosubstrates or their metabolites, which results in their accumulation in the medium. Addition of cosubstrates can regulate transformation stimulating accumulation of different products.