Enhancing photosynthetic CO2 fixation by assembling metal-organic frameworks on Chlorella pyrenoidosa

The CO₂ concentration at ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is crucial to improve photosynthetic efficiency for biomass yield. However, how to concentrate and transport atmospheric CO₂ towards the Rubisco carboxylation is a big challenge. Herein, we report the self-assembly of metal-organic frameworks (MOFs) on the surface of the green alga Chlorella pyrenoidosa that can greatly enhance the photosynthetic carbon fixation. The chemical CO₂ concentrating approach improves the apparent photo conversion efficiency to about 1.9 folds, which is up to 9.8% in ambient air from an intrinsic 5.1%. We find that the efficient carbon fixation lies in the conversion of the captured CO₂ to the transportable HCO₃^- species at bio-organic interface. This work demonstrates a chemical approach of concentrating atmospheric CO₂ for enhancing biomass yield of photosynthesis.