Marques Caterina G C, Andrade Leandro H, Toma Henrique E
Metalloenzymes and Mimetics Laboratory, Departamento de Química, Universidade Federal de São Carlos, Rodovia Washington Luis, s/n, Km 235, 13565-905 São Carlos, SP, Brazil.
Fine Chemistry and Biocatalysis Lab, Instituto de Quimica, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748, 05508-000 São Paulo, SP, Brazil.
An Acad Bras Cienc. 2017 Oct 16;90(1 Suppl 1):593-606. doi: 10.1590/0001-3765201720170330. Print 2018.
The conversion of carbon dioxide into important industrial feedstock is a subject of growing interest in modern society. A possible way to achieve this goal is by carrying out the CO2/methanol cascade reaction, allowing the recycle of CO2 using either chemical catalysts or enzymes. Efficient and selective reactions can be performed by enzymes; however, due to their low stability, immobilization protocols are required to improve their performance. The cascade reaction to reduce carbon dioxide into methanol has been explored by the authors, using, sequentially, alcohol dehydrogenase (ADH), formaldehyde dehydrogenase (FalDH), and formate dehydrogenase (FDH), powered by NAD+/NADH and glutamate dehydrogenase (GDH) as the co-enzyme regenerating system. All the enzymes have been immobilized on functionalized magnetite nanoparticles, and their reactions investigated separately in order to establish the best performance conditions. Although the stepwise scheme led to only 2.3% yield of methanol per NADH; in a batch system under CO2 pressure, the combination of the four immobilized enzymes increased the methanol yield by 64 fold. The studies indicated a successful regeneration of NADH in situ, envisaging a real possibility of using immobilized enzymes to perform the cascade CO2-methanol reaction.
将二氧化碳转化为重要的工业原料是现代社会中一个日益受到关注的课题。实现这一目标的一种可能方法是进行二氧化碳/甲醇级联反应，利用化学催化剂或酶实现二氧化碳的循环利用。酶可以进行高效且选择性的反应；然而，由于其稳定性较低，需要固定化方案来提高其性能。作者探索了将二氧化碳还原为甲醇的级联反应，依次使用乙醇脱氢酶（ADH）、甲醛脱氢酶（FalDH）和甲酸脱氢酶（FDH），由NAD⁺/NADH提供动力，并以谷氨酸脱氢酶（GDH）作为辅酶再生系统。所有酶都已固定在功能化的磁铁矿纳米颗粒上，并分别对其反应进行研究，以确定最佳性能条件。尽管分步方案每NADH仅产生2.3%的甲醇产率；但在二氧化碳压力下的间歇系统中，四种固定化酶的组合使甲醇产率提高了64倍。这些研究表明NADH在原位成功再生，设想了使用固定化酶进行二氧化碳 - 甲醇级联反应的实际可能性。
