In C3-type plants, Rubisco catalyzes the capture of carbon from CO2 during photosynthesis. Because Rubisco cannot distinguish between CO2 and oxygen molecules, around 35% of the time it binds with oxygen instead of carbon dioxide and produces a carbon molecule called glycolate instead. This product cannot be used in photosynthesis. The carbon however is salvaged by conversion via a complex network of enzyme reactions in multiple organelles into 3-phosphoglycerate (PGA), which can be used in photosynthesis. This process, called photorespiration, recovers 75% of the carbon lost by the oxygenation reaction but wastes energy that could otherwise be used in during photosynthesis.
Some bacteria have simpler pathways for converting glycolate to PGA that require less energy. RIPE is replacing the native pathway with these more efficient bacterial pathways to make photosynthesis more efficient.
Obstacles to implementation: This has already been successful in the model plant Arabidopsis, but not in food crops. Therefore, altering the pathway is a medium risk approach.