Photorespiration and carbon concentrating mechanisms: two adaptations to high O2, low CO2 conditions

This review presents an overview of the two ways that cyanobacteria, algae, and plants have adapted to high O₂ and low CO₂ concentrations in the environment. First, the process of photorespiration enables photosynthetic organisms to recycle phosphoglycolate formed by the oxygenase reaction catalyzed by ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Second, there are a number of carbon concentrating mechanisms that increase the CO₂ concentration around Rubisco which increases the carboxylase reaction enhancing CO₂ fixation. This review also presents possibilities for the beneficial modification of these processes with the goal of improving future crop yields.