Getting the green light

An international team of scientists has determined the structure of the chlorophyll molecules in green bacteria that are responsible for harvesting light energy.

The team’s results could one day be used to build artificial photosynthetic systems such as those that convert solar energy to electrical energy.

The scientists found that the chlorophylls are highly efficient at harvesting light energy.

‘We found that the orientation of the chlorophyll molecules make green bacteria extremely efficient at harvesting light,’ said Donald Bryant, professor of biotechnology at Penn State University in the US and one of the team leaders.

According to Bryant, green bacteria are a group of organisms that generally live in extremely low-light environments, such as in light-deprived regions of hot springs and at depths of 100m in the Black Sea. The bacteria contain structures called chlorosomes, which contain up to 250,000 chlorophylls.

‘The ability to capture light energy and rapidly deliver it to where it needs to go is essential to these bacteria, some of which see only a few photons of light per chlorophyll per day,’ he said.