A three-in-one heterogeneous catalyst (UPO@dTiO2-CD) was fabricated by grafting cyclodextrins (CDs) on the dehiscent TiO2 (dTiO2) surface and subsequently immobilizing unspecific peroxygenase (rAaeUPO), which exhibited double enhanced electron/mass transfer in photo-enzymatic enantioselective hydroxylation of the C–H bond. The tunable anatase/rutile phase ratio and dehiscent mesoporous architectures of dTiO2 and the electron donor feature and hydrophobic inner cavity of the CDs are independently responsible for accelerating both electron and mass transfer. The coordination of the photocatalytic and enzymatic steps was achieved by structural and compositional regulation. The optimized UPO@dTiO2-CD not only displayed high catalytic efficiency (turnover number and turnover frequency of rAaeUPO up to >65,000 and 91 min–1, respectively) but also exhibited high stability and reusability.
Chengxiang Feng,Jiacong Wu,Xinnan Ma,Juan Han,Lei Wang,Yun Wang
A novel photo-enzyme composite catalyst based on modified carbon nitride was constructed and applied in the removal of antibiotics and phenolic pollutants in water. This composite catalyst (Cyt c/C/CN) has high catalytic activity and stability under acidic or alkaline conditions, which broadens the application range of cytochrome c (Cyt c). In addition, it has A high degradation rate and mineralized rate for sulfadiazine (SDZ) and bisphenol A (BPA). Among them, the degradation and total organic carbon (TOC) removal rate of SDZ were 65.53% and 40.44% respectively, which were much higher than that of pure CN (50.83% and 9.76%). Moreover, the degradation and TOC removal rate of BPA were 72.53% and 44.66%, which were 1.3 times and 2.5 times that of pure CN, respectively. The findings provide insights for designing photo-enzyme coupling systems to efficiently and at a high level remove sulfonamides antibiotics and phenolic agricultural organic pollutants in a simple step.
By analogy to mono-nuclear metalloenzymes , single-atom dispersed catalysts (SACs) demonstrate very promising performance for many conventional heterogeneous and homogeneous reactions. However, the prospect of integrating SACs with enzymatic catalysis is still unexplored. Herein, atomically dispersed Co sites on ultrathin two-dimensional (2D) carbon nitride nanosheets (Co 1 /C 3 N 4 ) were constructed and applied for efficiently photochemical cofactor (NADH) regeneration. The NADH regeneration yield reached as high as 99%. Subsequently, the in-situ regenerated-NADH triggered alcohol dehydrogenase for enzymatic reduction of aldehyde where 100% alcohol yield was achieved. Using atomic spectroscopy characterization and theoretical calculation, the genuine active sites of Co 1 /C 3 N 4 catalyst in reaction system were revealed in the form of CoN 3 - Cp* moieties ( Cp* , 1,2,3,4,5-pentamethylcyclopentadiene). Such a well-defined atomic catalyst opens a new avenue for the organic transformation application of single-atom catalysts in enzyme catalysis.
An enzyme–photocatalyst hybrid system has been developed for aldehyde-based indole C-3 acylation. The concept of this process is to form a C–N bond through the three-component Mannich reaction of aldehydes, amines, and indoles, thereby introducing an aminomethyl group on the indole ring. Next, this system catalyzed the formation of the corresponding imide ion from the Mannich product, followed by rapid hydrolysis to give the final C-3 carbonyl indole product. More than 30 indole C-3 acylated products (up to 93% yield) were successfully synthesized under mild conditions, and indole derivatization of two bioactive substances (probenecid and cholesterol) was realized. The mechanistic study provides theoretical support for the construction of photoenzyme catalytic systems. This is an example of enzyme–light-activated C-3 acylation of indoles under very mild reaction conditions, without the use of transition metal catalysts, metal salts, and additional oxidants. This efficient enzyme–photocatalyst hybrid system provides a strategy for the development of photoenzyme catalysis fields.
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