Construction of a system for the regeneration of adenosine 5'-triphosphate, which supplies energy to bioreactor.

An engineering model was successfully developed for an ATP regeneration system by using two enzymes, acetate kinase (AK) and adenylate kinase (AdK), both obtained from the thermophile Bacillus stearothermophilus. This model is composed of five units: a substrate unit consisting of substrate solutions--AMP, ATP, and acetyl phosphate (AcOP)--an enzymatic reactor unit consisting of AK and AdK immobilized to Sepharose 4B, an auto sampler unit, an analytical unit made up of high-performance liquid chromatography, and a control unit made up of a microcomputer. Operation of the four units could be systematically controlled by the microcomputer. Fundamental, operational conditions were examined using this engineering model. The conversion of AMP to ATP concentration and space velocity (SV). The minimum amount of ATP, which is required to obtain the 100% conversion of AMP to ATP, was determined to be about 4% of AMP concentration. The conversion of AMP to ATP was controlled effectively by changing the SV value. Based on the above experimental data, the continuous operation of an ATP regeneration system was tested at pH 7.5 and 30 degrees C under the conditions of 1.59 mM AMP, 0.084 mM ATP, and 5.0 mM AcOP. It was found that the conversion of AMP to ATP was more than 99% over a period of 6 days without changing SV.