Enzymatic synthesis of fructose 1,6-diphosphate with ATP regeneration in abatch reactor and a semibatch reactor using purified enzymes of Bacillus stearothermophilus

The enzymatic synthesis of fructose 1,6-diphosphate (FDP), an important gly colytic intermediate whose applications in the field of medicine have gener ated a great deal of interest, was performed in a batch reactor and a semib atch reactor. Using the batch reactor, FDP was first synthesized from gluco se by three enzymatic reactions and the ATP consumed was regenerated simult aneously using conjugated enzymes, all of which were purified from crude ce ll extract of thermophilic Bacillus stearothermophilus. The results of the experiments performed using several enzyme concentrations suggest the exist ence of an optimum concentration for each enzyme at which the maximum FDP y ield can be attained. Since the thermal decomposition of acetyl phosphate r educed the yield of FDP in the batch reactor, the use of a semibatch reacto r in which acetyl phosphate was fed continuously was examined. The yield of FDP was improved but the time required to complete the reaction was longer , resulting in a lower productivity of FDP. The yields observed in the two reactors using various enzyme and substrate concentrations were in good agr eement with the theoretical predictions calculated based on differential eq uations derived for the system using the rate equations and the kinetic par ameters determined previously. This means that these equations can be used for the analysis of the experimental results as well as for determining the optimum experimental conditions.