Researchers have discovered a biological switch in blue-green algae that reacts to light, thereby altering the movement of electrons inside the cell. The new findings could help optimize biofuel production by algae.
Algae are prime targets for biofuel production. They are non-feedstock and will not compete with arable land for their growth and production. They have an explosive growth rate at optimum conditions, and they can use wastewater as a source of nutrients.
However, lack of light necessary for photosynthesis is a major constraint in algae biofuel production systems. Bioreactors usually employ energy-demanding mixing systems to provide adequate light to algae, or smaller and more expensive growth chambers.
Finding a way to optimize the growth of algae at low light conditions would be extremely beneficial. In order to do this, scientists need to fully understand how the biological molecules within algae cells respond to light.
Researchers examined the cyanobacteria species Synechococcus elogatus for this purpose. They attached green fluorescent protein tags to two key respiratory complexes in the species. Then the cyanobacteria cells were exposed to low and medium light conditions. Changes in the cells due to the light exposures were carefully studied using a microscope.
It was discovered that the brighter light caused reshuffling of the respiratory complexes from discrete patches into a uniform distribution throughout the cell. This redistribution appeared to be triggered by changes in the electrochemical charge of an electron carrier close to plastiquinone. The result was a greater probability that electrons would be transported to photosystem I, an integral component of the photosynthetic complex in the algae cell.
Conrad Mullineaux, microbiology professor at Queen Mary, University of London and co-author of the paper, comments that photosynthesis depends on tiny electrical circuits operating within biological membranes. Their research group is trying to determine what controls these circuits, what makes electrons take a specific route, and what switches are available to send electrons to other destinations. He adds that findings from the study could be exploited in engineering algae for improved biofuel production.
The research was a collaboration of scientists from Queen Mary, University of London, the Imperial College London and the University College London. The results of the research were published in the Proceedings of the National Academy of Sciences.