The purpose of this work was to study the conditions for the reaction of co-oxidation of pyridine by seven strains of Pseudomonas using succinic acid, glucose, and sodium salicylate and benzoate as a growth substrate. The structure of a growth substrate was shown to influence pyridine oxidation. The dependence of co-oxidation on the nature of a growth substrate seems to stem from the electron structure of substrate and cosubstrate molecules.