Ordered Coimmobilization of a Multienzyme Cascade System with a Metal Organic Framework in a Membrane: Reduction of CO₂ to Methanol

Abstract

Enzymatic reduction of CO2 is of great significant, which involves an efficient multienzyme cascade system (MECS). In this work, formate dehydrogenase (FDH), glutamate dehydrogenase (GDH), and reduced pyridine nucleotide (NADH) (FDH&GDH&NADH), formaldehyde dehydrogenase (FalDH), GDH, and NADH (FalDH&GDH&NADH), and alcohol dehydrogenase (ADH), GDH, and NADH (ADH&GDH&NADH) were embedded in ZIF-8 (one kind of metal organic framework) to prepare three kinds of enzymes and coenzymes/ZIF-8 nanocomposites. Then by dead-end filtration these nanocomposites were sequentially located in a microporous membrane, which was combined with a pervaporation membrane to timely achieve the separation of product methanol. Incorporation of the pervaporation membrane was helpful to control reaction direction, and the methanol amount increased from 5.8 ± 0.5 to 6.7 ± 0.8 μmol. The reaction efficiency of an immobilized enzymes-ordered distribution in a membrane was higher than that disordered distribution in the membrane, and the methanol amount increased from 6.7 ± 0.8 to 12.6 ± 0.6 μmol. Moreover, it appeared that introduction of NADH into ZIF-8 enhanced the transformation of CO2 to methanol from 12.6 ± 0.6 to 13.4 ± 0.9 μmol. Over 50% of their original productivity was retained after 12 h of use. This method has wide applicability and can be used in other kinds of multienzyme systems.

Multi‐enzyme Cascade Reactions in Metal‐organic Frameworks

“…Reprinted with permission. [50] Copyright 2019, American Chemical Society. Recently, Ni and co-workers also developed a strategy to sequentially co-immobilize multi-enzyme within MOF on membranes.…”

“…Recently, Ni and co-workers also developed a strategy to sequentially co-immobilize multi-enzyme within MOF on membranes. [50] ADH/GDH/NADH, FDH/GDH/NADH, and FalDH/GDH/NADH were co-encapsulated in ZIF-8, respectively, to fabricate multi-enzyme@ZIF-8 nanocomposites. These biocatalytic MOFs were orderly positioned on a porous membrane via dead-end filtration strategy, then integrated with a pervaporation membrane to rapidly isolate the generated methanol from the alcohol/water mixture (Figure 3d).…”

“…After 12 h of utilization, more than 50 % of initial activity was remained. [50] Overall, the multi-enzyme could be positional co-immobilized within MOFs by specific cross-linking with each other via complementary conjugation, or positional co-immobilized in the interior or exterior of MOFs according to the sequence of multi-enzyme cascade reactions. Usually the enzymes involved in the first biocascade step are positioned on the exterior of MOF.…”

“…[34,35,48] Moreover, by selecting the appropriate MOF materials for immobilization, multi-enzyme cascade reactions can be accurately controlled by the spatially positioned and orientated enzymes in nanoscale-precision. [39,49,50] In addition, to endow multi-enzyme catalysis with the smart and stimuli-responsive property, compartmentalization of enzymes sometimes is required to provide a separated space for different enzymes, which is helpful to regulate enzymes and enhance their whole catalytic performance. [41,55,56] More excitingly, with the merits of compartmentalization strategy and communication capability of MOFs, some chemically incompatible enzymes (e. g. protease and glucose oxidase) can be coupled together to function cooperatively for chemical synthesis.…”

CO<sub>2</sub> chemical engineering: CO<sub>2</sub> green conversion enhanced by ionic liquid microhabitat

“…Chen等 [95] 将酶促反应与辅助因子的电 化学再生相结合, 通过共沉积FDH, 用Cp*Rh修饰的含 氟 的 氧 化 锡 玻 璃 电 极 形 成 了 介 孔 金 属 -有 机 骨 架 (MOF) (NU-1006), 建立了非生物电催化体系, 使甲酸 产量达到79 mM h −1 . Zhu等 [96] [92] (网络版彩图)…”