Fixing carbon, unnaturally
A synthetic enzymatic pathway is more energy efficient than natural aerobic carbon fixation pathways Rising atmospheric carbon dioxide (CO2) concentration as a result of extensive use of fossil fuel resources is one of the main causes of global warming. Natural photosynthesis converts 100 billion tons of CO2 into biomass annually (1) Although natural photosynthesis plays a vital role in absorbing CO2 emitted from fossil fuel use, it cannot prevent the net increase of atmospheric CO2 concentration since the Industrial Revolution. Natural CO2 fixation is mainly achieved by a CO2 fixation pathway called the Calvin cycle, in which ribulose 1,5 bisphosphate carboxylase/oxygenase (RuBisCO) is the key enzyme. To date, six CO2 fixation pathways, including the Calvin cycle, have been discovered (2) On page 900 of this issue, Schwander et al. (3) report a synthetic CO2 fixation pathway that is more energy efficient than the Calvin cycle, expanding the capabilities for recapturing atmospheric CO2 for use as a carbon feedstock.
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