The present work investigated the inorganic carbon (C-i) uptake, fluorescence quenching and photo-inhibition of the edible cyanobacterium Ge-Xian-Mi (Nostoc) to obtain an insight into the role of CO2 concentrating mechanism (CCM) operation in alleviating photo-inhibition. Ge-Xian-Mi used HCO3- in addition to CO2 for its photosynthesis and oxygen evolution was greater than the theoretical rates of CO2 production derived from uncatalysed dehydration of HCO3-. Multiple transporters for CO2 and HCO3- operated in air-grown Ge-Xian-Mi. Na+-dependent HCO3- transport was the primary mode of active C-i...
