Work

O2-tolerant CO dehydrogenase via tunnel redesign for the removal of CO from industrial flue gas

Year: 2022

Type: article

Abstract: Carbon monoxide dehydrogenase (CODH)-catalyzed oxidation of CO to CO2 provides a promising means of removal of toxic and waste CO from industrial flue gas despite of the lack of active and stable enzymes in the atmosphere. Herein we present rationally and selectively redesigned ChCODH-II (Carboxydothermus hydrogenoformans) variants by engineering gas tunnels in order for O2-tolerant CODHs to catalyze efficient CO oxidation under oxygen (O2). Using the redesigned ChCODH-II A559W and A559H variants showing 42- and 128-fold elevation of O2 tolerance, respectively, complete CO removal was achieved under a near-atmospheric condition. Moreover, these variants efficiently removed CO from industrial flue gas (Linz–Donawiz converter Gas: LDG) discharged from a steel mill despite the high O2 level (13.4%) during successful and repeated reuse after immobilized on Ni-NTA agarose beads. Our study will provide insights into redesigning the transformation of O2-sensitive CODHs into tolerant enzymes for use as workhorses for conversion of toxic or waste gases into safe or value-added chemicals.

Source: Nature Catalysis

DOI: 10.1038/s41929-022-00834-y