Inspired by water‐forming NAD(P)H oxidases, a cooperative photobiocatalytic system has been designed to aerobically regenerate the oxidized nicotinamide cofactors. Photocatalysts enable NAD(P)H oxidation with O2 under visible‐light irradiation, producing H2O2 as a byproduct, which is subsequently used as an oxidant by the horseradish peroxidase mediator system (PMS) to oxidize NAD(P)H. The photobiocatalytic system shows a turnover frequency of 8800 min−1 in the oxidation of NAD(P)H. Photobiocatalytic NAD(P)H oxidation proceeds smoothly at pH 6–9. In addition to natural NAD(P)H, synthetic biomimetics are also good substrates for this regeneration system. Total turnover numbers of up to 180000 are obtained for the cofactor when the photobiocatalytic regeneration system is coupled with dehydrogenase‐catalyzed oxidations. It may be a promising protocol to recycle the oxidized cofactors for catalytic oxidations.

NAD(P)+ regeneration is of great importance for dehydrogenase (DH)‐catalyzed oxidations. In this work, we report horseradish peroxidase (HRP)‐catalyzed aerobic oxidation of the reduced nicotinamide cofactors, including natural and non‐natural ones, into the oxidized form at neutral and alkaline pH enabled by external amino acids (AAs). HRP showed promiscuous yet extremely low oxidase activity toward NADH at pH 7 in the absence of both AAs and mediators, as evidenced by the observation of compound III. The mechanistic study revealed that AAs as decoy molecules (likely act as acid‐base catalysts) and mediators significantly promoted the formation of compound III as well as its decay back to the ground state. The applicability of the aerobic cofactor regeneration method was demonstrated by the HRP total turnover number up to 88 000 as well as high yields (91–99 %) in bi‐enzymatic synthesis of carboxylic acids. The present work offers an alternative method to recycle NAD(P)+. Also, it may open up possibilities for HRP‐catalyzed aerobic oxidations.

Invited for this month′s cover is the group of Ning Li at South China University of Technology. The image shows an efficient photobiocatalytic system to regenerate oxidized nicotinamide cofactors for dehydrogenase‐mediated oxidations. The Communication itself is available at 10.1002/cssc.202100184.

The Front Cover shows an efficient photobiocatalytic system comprising photocatalyst and horseradish peroxidase to regenerate oxidized nicotinamide cofactors for dehydrogenase‐mediated oxidations. The combined advantages of high‐molecular‐weight biocatalyst (high efficiency) and low‐molecular‐weight chemical catalyst (broad pH and substrate tolerance) are demonstrated. A turnover frequency of up to 8800 min−1 is obtained. Besides, photobiocatalytic oxidation of NAD(P)H and inexpensive synthetic biomimetics proceeds smoothly at pH 6–9. Total turnover numbers of up to 180000 are obtained for the cofactor when the photobiocatalytic regeneration system is coupled with dehydrogenase‐catalyzed oxidations. More information can be found in the Communication by H.‐X. Liao et al.