Molar-scale formate production via enzymatic hydration of industrial off-gases
Jinhee Lee, Suk Min Kim, Byoung Wook Jeon, Ho Won Hwang, Eleni G. Poloniataki, Jingu Kang, Sanghyung Lee, Ho Won, Jonggeol Na, Jeong‐Geol Na, Jinwon Lee, Yong Hwan Kim
Abstract
Abstract Decarbonizing the steel industry, a major CO 2 emitter, is crucial for achieving carbon neutrality. Escaping the grip of CO combustion methods, a key contributor to CO 2 discharge, is a seemingly simple yet formidable challenge on the path to industry-wide net-zero carbon emissions. Here we suggest enzymatic CO hydration (enCOH) inspired by the biological Wood‒Ljungdahl pathway, enabling efficient CO 2 fixation. By employing the highly efficient, inhibitor-robust CO dehydrogenase ( Ch CODH2) and formate dehydrogenase ( Me FDH1), we achieved spontaneous enCOH to convert industrial off-gases into formate with 100% selectivity. This process operates seamlessly under mild conditions (room temperature, neutral pH), regardless of the CO/CO 2 ratio. Notably, the direct utilization of flue gas without pretreatment yielded various formate salts, including ammonium formate, at concentrations nearing two molar. Operating a 10-liter-scale immobilized enzyme reactor feeding live off-gas at a steel mill resulted in the production of high-purity formate powder after facile purification, thus demonstrating the potential for decarbonizing the steel industry.