Photosynthesis is a process by which biological entities utilize sunlight and CO2 to produce sugars for energy. Photosynthesis, as naturally evolved, is an extremely complex system with numerous and poorly understood feedback loops, control mechanisms, and process inefficiencies. This complicated system presents likely insurmountable obstacles to either one-factor-at-a-time or global optimization approaches [Nedbal et al., Photosynth Res., 93(1-3):223-34 (2007); Salvucci et al., Physiol Plant., 120(2):179-186 (2004); Greene et al., Biochem J., 404(3):517-24 (2007)].
Existing photoautotrophic organisms (i.e., plants, algae, and photosynthetic bacteria) are poorly suited for industrial bioprocessing and have therefore not demonstrated commercial viability for this purpose. Such organisms have slow doubling time (3-72 hrs) compared to industrialized heterotrophic organisms such as Escherichia coli (20 minutes), reflective of low total productivities. In addition, techniques for genetic manipulation (knockout, over-expression of transgenes via integration or episomic plasmid propagation) are inefficient, time-consuming, laborious, or non-existent.