Abstract
Production of theobromine from caffeine by caffeine-degrading bacteria was studied. We found that addition of metal ions such as Zn2+ to intact cells of a caffeine-degrading isolate from soil, Pseudomonas sp. No. 6, resulted in a high theobromine accumulation from caffeine. We hypothesized that Zn2+ acts as a selective inhibitor of one of the theobromine-demethylating enzymes and further screened for theobromine-producing activities in the presence of Zn2+ among a number of caffeine-using microorganisms. A strain identified taxonomically as Pseudomonas putida No. 352 showed the best productivity among 973 microorganisms of stock cultures and soil isolates. Culture conditions for the production of theobromine from caffeine by P. putida No. 352 were studied. Under optimal conditions, nearly 20 g/liter of theobromine was produced from caffeine in a yield of 92%.
