Abstract:

The massive combustion of fossil fuels increases the emission of the greenhouse gas CO₂, which has a bad impact on the environment. The capture and conversion of CO₂ into high value-added chemicals is a win-win strategy to achieve energy conservation and emission reduction and turn waste into treasure. Enzyme-catalyzed CO₂ capture and conversion has such advantages as high efficiency, high selectivity, mild reaction conditions, and environmental friendliness. Carbonic anhydrase (CA) can greatly accelerate CO₂ hydration reaction, while formate dehydrogenase (FDH) can catalyze the reduction of CO₂ to formate, and the synergy of CA and FDH can enhance CO₂ reduction kinetics. However, in the industrial application of enzymatic reactions, factors such as temperature, pH, and the type and concentration of other ions may lead to the inactivation of the enzyme. Therefore, the study on the enzyme stability is vital. In this review, the research progress of the stability of CA and FDH and the effect of immobilization on the stability of enzymes are reviewed from the perspectives of thermal stability, acid-base stability and ionic stability. Strategies for improving the enzyme stability include the use of extremophiles, the rational design and modification of enzyme molecules, in which the effect of the immobilization method on the stability of enzyme is elaborated, providing reference for future industrial applications.

Key words: carbonic anhydrase, formate dehydrogenase, biocatalysis, stability, immobilization, CO₂ capture and conversion

摘要：

化石燃料的大量燃烧使温室气体CO₂的排放量不断增加，对环境造成恶劣影响，将CO₂捕集并转化为高附加值化学品是实现节能减排和变废为宝的一种双赢策略。酶催化CO₂捕集和转化具有高效、高选择性、反应条件温和、环境友好等优点。碳酸酐酶（CA）可大大加速CO₂水合反应，而甲酸脱氢酶（FDH）可催化CO₂还原为甲酸，二者协同可增强CO₂还原动力学。但酶促反应的工业化应用过程中，酶所处环境的温度、酸碱度以及其他离子的种类和浓度等因素均可能导致酶失活，因此，酶的稳定性研究至关重要。本文从热稳定性、酸碱稳定性和离子稳定性的角度，综述了CA和FDH的稳定性研究进展。改善酶稳定性的手段包括使用极端微生物、酶分子设计与改造、固定化等，重点讨论了固定化对酶稳定性的提升效果，为未来的工业化应用提供参考。

关键词: 碳酸酐酶, 甲酸脱氢酶, 生物催化, 稳定性, 固定化, CO₂捕集和转化