Unique New Species of Light-Harvesting Bacteria

In the bubbling muck of Yellowstone National Park, scientists have discovered a new species of bacteria that uses light for energy. Known as Candidatus Chloracidobacterium thermophilium, the new species is different than other types of photosynthetic bacteria, such as cyanobacteria (also called blue-green algae): it carries an antenna loaded with the light-harvesting molecule chlorophyll, which allows it to compete with other species living in the hot springs’ brightly colored microbial mats. The findings are published today in the journal Science.

Scientists discovered the bacterium using metagenomics, a variation on genomics that entails sequencing the genomes of entire microbial communities in order to identify new species. Metagenomics provides microbiologists with a new way to identify novel bacterial species, the vast majority of which can’t be grown in the lab. (See “Our Microbial Menagerie” and “Why Termite Guts Could Bring Better Biofuels.”)

The steaming pools of Yellowstone, which can reach higher than 150 ºF, were also the site of one of the most important microbial discoveries of molecular biology: Thermus aquaticus, a heat-loving bacterium that gave scientists an enzyme crucial for efficiently replicating DNA. Researchers hope that the recent discovery will shed light on how bacteria efficiently harvest light, perhaps inspiring new ways to make energy.