Enzymes for CO2 fixation: Discovery, engineering, and applications.

Carbon dioxide (CO2) is the primary contributor to greenhouse gas emissions and a key driver of climate change. Over the past few decades, CO2 utilization has increasingly attracted interest, presenting a critical pathway toward a sustainable, carbon-neutral bioeconomy. Enzymatic CO2 fixation elucidates and modulates CO2 sequestration efficiency by analyzing biochemical reaction pathways, laying a foundation for the design of integrated, high-performance sequestration systems. This review summarizes naturally occurring CO2-fixation enzymes and their catalytic mechanisms, as well as the design and construction strategies for artificial CO2-fixation pathways. We further explored the biocatalytic utility of carboxylases and decarboxylases in the biosynthesis of high-value compounds, while summarizing methodologies to enhance the efficiency of these processes. Significantly, this review bridges fundamental mechanistic insights with scalable biocatalytic applications, highlighting CO2 treatment as a valuable resource rather than a risk. In future research, powerful and efficient multi enzyme cascade systems and bioreactor designs should be developed to economically convert carbon dioxide into valuable products.