Bioconversion of pyrimidine by resting cells of quinoline-degrading bacteria

Nine quinoline-degrading bacterial strains were tested for their ability to hydroxylate pyrimidine. All strains converted pyrimidine to uracil via pyr imidine-4-one in a cometabolic process. Quinoline 2-oxidoreductases (QuinOR s) were the catalysts of fortuitous pyrimidine hydroxylation. Whereas in mo st strains the activity of the QuinOR towards pyrimidine was very low compa red to its activity towards quinoline, QuinOR in crude extracts from Comamo nas testosteroni 63 showed a specific activity of 64 (mU mg protein)(-1) wi th pyrimidine as substrate, compared to a specific activity of 237 (mU mg p rotein)(-1) towards the intrinsic substrate quinoline. Resting cells of Com amonas testosteroni 63 rapidly converted pyrimidine almost stoichiometrical ly to uracil, which accumulated in the cell suspension. Using an adsorbent resin, uracil was prepared from the supernatant of Comamonas testosteroni 6 3 resting cells with a yield of >98%. (C) 1999 Federation of European Micro biological Societies. Published by Elsevier Science B.V. All rights reserve d.