Practical Processing with Cofactor -Requiring Enzymes

Abstract

Abstract The use of cofactor requiring enzymes in practical processes is dependent on regeneration and multiple reuse of the cofactor. Various methods currently available for the accomplishment of this goal are evaluated. We conclude that, in most instances, enzymatic regeneration techniques are superior to chemical regeneration techniques. We also conclude that, except in very unusual cases, cofactor regeneration and reuse is most efficient when processing enzymes as well as cofactor regenerating enzymes are contained in the same reactor. A cofactor classification based on regeneration requirements is proposed. Methods for the retention of both modified (for example, macro molecular) and native cofactors within the process reactor are discussed, as well as various cofactor recovery techniques. Finally, a prototype enzyme reactor employing native cofactor without retention, and allowing high substrate to product conversion with an extremely high number of cofactor cycles, is proposed. Utilizing this reactor, we were able to effect 99% conversion of sorbitol to fructose with 20, 000 NAD turnovers.