Chlorogloeopsis fritschii – an alga that thrives in low levels of light. Courtesy A. K. Mitra et D. C. Pandey, Culture Collection of Autotrophic Organisms

Chlorogloeopsis fritschii – an alga that thrives in low levels of light. Courtesy A. K. Mitra et D. C. Pandey, Culture Collection of Autotrophic Organisms

Researchers working on the EnAlgae project at Plymouth Marine Laboratory have made a discovery that some algae strains are better able to make use of the low levels of light found when the algae are cultured on a large scale. Dr. Ruth Airs and co-workers, working with Dr. Carole Llewellyn, discovered that the cyanobacterium Chlorogloeopsis fritschii produces unusual chlorophylls that absorb long wavelength light (>700 nm) when grown under near infrared, or when grown to high culture density in a photobioreactor (PBR) under natural light.

The maximum photon flux of sunlight is at 700 nm, and the ability to use light in the region 700-750 nm increases the number of available photons by 19%. Although the longest wavelength photon that can drive oxygenic photosynthesis is currently unclear, this represents a substantial potential increase in efficiency. Some cyanobacteria are naturally capable of doing this and show extensive transcriptional changes when grown under far-red light, and that this far red light photo acclimation improves red-light photosynthetic performance.

“This is an interesting discovery,” said Dr Llewellyn. “We have shown that Chlorogloeopsis uses this far-red light machinery under high biomass PBR conditions in sunlight, which may help to explain the ability of this organism to grow to high cell densities in a PBR.”

“The potential benefits from applying additional red light, and whether the benefits can be transferred to algae and higher plants have yet to be explored. And this may be a field of work to be undertaken in the future.”

The paper “Chlorophyll f and chlorophyll d are produced in the cyanobacterium Chlorogloeopsis fritschii when cultured under natural light and near-infrared radiation” is published in FEBS Letters.

The EnAlgae project is led by Swansea University and funded by the European Union under the INTERREG IVB North West Europe programme. EnAlgae unites experts and observers from 7 EU member states to determine the potential benefits of algae as a future sustainable energy source.