Pickering-Droplet-Derived MOF Microreactors for Continuous-Flow Biocatalysis with Size Selectivity

Abstract

Enzymatic microarchitectures with spatially controlled reactivity, engineered molecular sieving ability, favorable interior environment, and industrial productivity show great potential in synthetic protocellular systems and practical biotechnology, but their construction remains a significant challenge. Here, we proposed a Pickering emulsion interface-directed synthesis method to fabricate such a microreactor, in which a robust and defect-free MOF layer was grown around silica emulsifier stabilized droplet surfaces. The compartmentalized interior droplets can provide a biomimetic microenvironment to host free enzymes, while the outer MOF layer secludes active species from the surroundings and endows the microreactor with size-selective permeability. Impressively, the thus-designed enzymatic microreactor exhibited excellent size selectivity and long-term stability, as demonstrated by a 1000 h continuous-flow reaction, while affording completely equal enantioselectivities to the free enzyme counterpart. Moreover, the catalytic efficiency of such enzymatic microreactors was conveniently regulated through engineering of the type or thickness of the outer MOF layer or interior environments for the enzymes, highlighting their superior customized specialties. This study provides new opportunities in designing MOF-based artificial cellular microreactors for practical applications.

MOF‐Hosted Enzymes for Continuous Flow Catalysis in Aqueous and Organic Solvents

“…Tian et al. reported a continuous flow reactor filled with MOF coated micelles containing the enzyme CALB [25] …”

“…Tian et al reported a continuous flow reactor filled with MOF coated micelles containing the enzyme CALB. [25] In other catalytic applications of MOFs, [26,27] continuousflow, packed-bed reactors [28,29] showed substantial differences to batch experiments. Therefore, investigating Enzyme@MOF systems in a flow reactor is a crucial next step towards real world applications.…”

In MOF eingebettete Enzyme für die kontinuierliche Durchflusskatalyse in wässrigen und organischen Lösungsmitteln

“…Tian et al. berichteten über einen Durchflussreaktor, gefüllt mit MOF‐beschichteten Mizellen, die das Enzym CALB enthielten [25] …”

Selective catalysis in a cellular microenvironment—a living cell catalytic system with intracellular nanopalladium for olefin hydrogenation

“…1,2 Many efforts have been devoted to improving the catalytic selectivity of metal nanocatalysts. For example, nanopalladium is loaded into the pores of MOFs, [3][4][5][6][7][8][9][10][11][12] or into the channels of molecular sieves, [13][14][15] or into the apo-ferritin cage, 16 so as to form a selective catalytic system with the action of a carrier. [17][18][19] Although the selectivity of these catalytic systems did improve significantly, they struggle to compete with self-reproducible, green synthetic and recyclable biocatalysts.…”

“…Therefore, it is of great interest for us to couple the high catalytic selectivity of living cells with the high activity of nano-metal catalysts, exploring the selectivity of the living cell catalytic systems, including the intracellular enzyme-like metal nanocatalysts with high activity, 23,24 and the cell membrane with high selectivity. 10,25 The LCCSs not only have high selectivity, self-replication and recyclability but also have high activity and stability due to the dispersing and stabilizing effects of intracellular proteins, 26 which might open unforeseen opportunities to achieve the multitudinous special catalytic processes that do not occur in natural catalytic systems for desirable chemical applications.…”