Photosynthetic microorganisms are capable of adapting to a wide range of CO2 concentrations. When cyanobacterial cells are transferred from high to low concentrations of CO2, they undergo an adaptation process. This includes modulation of the expression of certain genes, some of which are involved in the operation of the inorganic carbon (Ci)-concentrating mechanism (CCM, see Miller et al. 1990; Kaplan et al. 1991; Raven 1991; Badger, Price 1992; Ogawa 1993 and Kaplan et al. 1994 for recent reviews and literature citations). The active accumulation of Ci to levels as high as 50-100 mM Ci, consequent on the activity of the CCM, enables the cells to perform efficient photosynthesis in spite of the relatively low affinity of their ribulose 1,5- bisphosphate carboxylase (rubisco) for CO2. Moreover, the elevated concentration of CO2 in close proximity to rubisco, within the carboxysomes, activates the enzyme, reduces competition by O2 and inhibits photorespiration (Schwarz et al. 1995)
Photosynthetic microorganisms are capable of adapting to a wide range of CO2 concentrations. When cyanobacterial cells are transferred from high to low concentrations of CO2, they undergo an adaptation process. This includes modulation of the expression of certain genes, some of which are involved in the operation of the inorganic carbon (Ci)-concentrating mechanism (CCM, see Miller et al. 1990; Kaplan et al. 1991; Raven 1991; Badger, Price 1992; Ogawa 1993 and Kaplan et al. 1994 for recent reviews and literature citations). The active accumulation of Ci to levels as high as 50-100 mM Ci, consequent on the activity of the CCM, enables the cells to perform efficient photosynthesis in spite of the relatively low affinity of their ribulose 1,5- bisphosphate carboxylase (rubisco) for CO2. Moreover, the elevated concentration of CO2 in close proximity to rubisco, within the carboxysomes, activates the enzyme, reduces competition by O2 and inhibits photorespiration (Schwarz et al. 1995)