C3 carbon fixation

C3 plants cannot grow in very hot areas at today's atmospheric CO2 level (significantly depleted during hundreds of millions of years from above 5000 ppm) because RuBisCO incorporates more oxygen into RuBP as temperatures increase.

This improvement might be due to its ability to recapture CO2 produced during photorespiration, a behavior termed "carbon refixation".

[6] C3 carbon fixation is prone to photorespiration (PR) during dehydration, accumulating toxic glycolate products.

In the 2000s scientists used computer simulation combined with an optimization algorithm to figure out what parts of the metabolic pathway may be tuned to improve photosynthesis.

In 2019, they transferred Chlamydomonas reinhardtii glycolate dehydrogenase and Cucurbita maxima malate synthase into the chloroplast of tobacco (a C3 model organism).

By forgoing all transport among organelles, all the CO2 released will go into increasing the CO2 concentration in the chloroplast, helping with refixation.