Figure 1.

Schematic of native PR and of five synthetic bypasses to this pathway. Native PR is shown by black arrows, where brown arrows highlight especially wasteful reactions. The glycerate pathway (chloroplastic version shown in purple and peroxisomal version in pink) and the glycolate complete oxidation pathways (green arrows) have already been tested in plants, but all result in the release of CO₂. The arabinose 5-phospate pathway (blue arrows) is a carbon-conserving route, assimilating glycolate to the CBC without the loss of CO₂. Red arrows show a potential pathway that harnesses the low reduction potential in the chloroplast to reduce CO₂ to formate, which is then assimilated into the photorespiratory pathway, transforming it into a carbon-fixing route.