A NOVEL PATHWAY FOR THE METABOLISM OF CAFFEINE BY A MIXED CULTURE CONSORTIUM

A new oxidative pathway for the degradation of caffeine(1,3,7-Trimethy lxanthine, I) by a mixed culture consisting of strains belonging to th e genera Klebsiella and Rhodococcus is presented. The mixed culture do es not initiate degradation by N-demethylation either complete or part ial, but instead carries out oxidation at the C-8 position resulting i n the formation of 1,3,7-trimethyluric acid (TMU, II) which further ge ts degraded to 3,6,8-trimethylallantoin (TMA, III), Both TMU and TMA a re hitherto not shown to be formed in the microbial system. Further de gradation of TMA (LII) by caffeine grown cells yields dimethylurea (Vm as one of the metabolites, Oxygen uptake studies indicated that caffe ine(I) grown cells oxidized TMU(II), TMA (III), glyoxalic acid (VI), d imethylurea(VII), and monomethylurea(V), but not monomethyl and dimeth yluric acids. The mixed culture does not accept theophylline(l,3-dimet hylxanthine), theobromine(3,7-dimethylxanthine), and paraxanthine(l,7- dimethylxanthine) as the carbon source. (C) 1998 Academic Press.