Zaixiang Xu,Fengcang Zhou,Hanchi Chen,Jianguo Wang
The regeneration of NAD(P)H and its analogues is crucial for biocatalytic processes. However, despite the efficiency of enzymatic catalysis in regenerating NAD(P)H, the sustainability of enzymes is often compromised, particularly under extreme catalytic conditions. Moreover, artificial cofactors may present advantages in certain reactions due to their stability and versatility, yet the substrate specificity of enzymes poses significant challenges to their regeneration through the enzymatic method. Therefore, it is imperative to develop a highly stable regeneration method that can be adapted to both natural and artificial cofactors. In this work, employing potassium-ion-doped carbon nitride (ionCN-0.2) as a catalyst not only achieves high-efficiency photocatalytic regeneration of NAD(P)H, comparable to that of glucose dehydrogenase (GDH), but also a remarkable ability to regenerate nicotinamide analogues. This enhanced performance stems from the tunable negative ζ-potential, which effectively adsorbs the positively charged [Cp*Rh(bpy)H2O]2+ mediator, resulting in enhanced regeneration kinetics of the nicotinamide moiety. The catalyst demonstrates superior performance compared to the reported systems; the optimal regeneration rate reaches 0.55 mmol L–1 gcat–1 min–1 and approaches enzymatic regeneration efficiency. Expanding the reaction conditions to a wider temperature and pH range also confirms the effectiveness and sufficient stability of this photocatalytic system, offering a promising strategy for stable cofactor regeneration in biocatalytic processes.
An organometallic complex-catalyzed artificial coenzyme regeneration system has attracted widespread attention. However, the combined use of organometallic complex catalysts and natural enzymes easily results in mutual inactivation. Herein, we establish a rhodium-based metal–organic framework (MOF)-on-MOF difunctional core–shell nanoreactor as an artificial enzymatic NAD(P)H regeneration system. UiO67 as the core is used to capture rhodium molecules for catalyzing NAD(P)H regeneration. UiO66 as the shell is used to specifically immobilize His-tagged lactate dehydrogenase (LDH) and serve as a protection shield for LDH and [Cp*Rh(bpy)Cl]+ to prevent mutual inactivation. A variety of results indicate that UiO67@Rh@UiO66 has good activity in realizing NAD(P)H regeneration. Noteworthily, UiO67@Rh@UiO66@LDH maintains a high activity level even after 10 cycles. This work reports a novel NAD(P)H regeneration platform to open up a new avenue for constructing chemoenzyme coupling systems.
Controllable and mild photoenzymatic production of chiral alcohols was realized by coupling a versatile photochemical NAD(P)H regeneration system with (R)- or (S)-selective ketoreductases. The efficiency of NAD(P)H regeneration was improved using a Rhodium functionalized metal organic framework, namely Rh-UiO-67, to adjust and control electron transport and electron utilization. Furthermore, six different ketoreductases could be successfully immobilized on Rh-UiO-67 and combined with the light-driven NAD(P)H regeneration system to produce chiral aryl alcohols. Various chiral alcohols with complementary (R)- and (S)-conformations can be constructed by this method with high yields (97%) and excellent stereoselectivity (>99% ee).