Cu/nucleotide coordination self-assembling to in situ regenerate NAD(P)+ and co-immobilize dehydrogenase with robust activity and stability

Abstract

Enzyme is an efficient green catalyst, but its vulnerability and difficulties of separation from products limited the application in industry. Furthermore, a large number of oxidase enzymes rely on dihydronicotinamide adenine dinucleotide (NADH) or dihydronicotinamide adenine dinucleotide phosphate (NADPH) cofactors. These cofactors are too expensive to be used in industrial processes. Thus, cofactor regeneration is an important method to avoid the consumption of large quantities of oxidized cofactor NAD(P)+ in enzyme-catalyzed reactions. In this paper, Cu based metal nucleotides coordination polymers (MNCPs) with NAD(P)H oxidase activity were constructed by self-assembly of copper ions and nucleotides. Cu2+/AMP and Cu2+/GMP showed high catalytic activity and high reusability. Then, Cu2+/AMP with NADH oxidase activity was combined with NAD+ dependent alcohol dehydrogenase (ADH) to construct a bienzyme cascade system with circulating cofactor, which applied to the conversion of benzyl alcohol to benzaldehyde. In this system, ADH exhibited high activity due to the increase of substrate concentration and the inhibition of the diffusion of intermediate products. Besides, the bienzyme cascade system also showed high stability and reusability. After 8 cycles, the immobilized ADH remained more than 57% of the initial activity. The prepared bienzyme cascade system can extensively extended its application in industrial production.