Membrane Bioreactor with Regeneration of Dissociable Coenzymes.

The bioreactor with regeneration of dissociable coenzymes, such as NAD, NADP and ATP, have been the major target in the development of the second generation bioreactor. The bioreactors with coenzyme regeneration are classified into two categories. In the first category, the coenzymes are chemically modified and bound to water-soluble macromolecules, which enables complete immobilization of coenzymes along with enzymes, typically, in the membrane reactor. In the second category, the coenzymes are partially immobilized in the reactor system either though (1) reaction dynamics between the coenzymes and enzymes, (2) electrical repulsion between the coenzymes and negatively charged membrane, or (3) rejection to the coenzymes by nanofiltration membrane. Among those, the method with nanofiltration membrane seems most promising because of no neccesity for the chemical modification of coenzymes and its general applicability to all of the dissociable coenzymes.