Spectral expansion and antenna reduction can enhance photosynthesis for energy production

• Efficiency of natural photosynthesis is reviewed.
• Effects of expansion of the solar spectrum into the near infrared are discussed.
• Penetration of sunlight light through the water column is discussed.
• Effects of reduction of antenna size on light response curves are discussed.

We consider two approaches for improving the efficiency of photosynthesis: the expansion of the solar spectrum that drives oxygenic photosynthesis and the reduction of antenna systems that couple to the photochemical reaction center. The first approach can possibly result in an increase of 19% in the number of photons available per unit area if the photosynthetically active radiation spectrum is expanded to 750 nm. The second approach can in principle shift the photosynthesis light response curve to significantly higher intensities, thereby reducing the amount of excess light, which is absorbed photons in excess of the number that can be utilized. The implementation of these approaches may lead to apparent improvement in photosynthetic efficiency in many but not all the cases.