Some current research efforts are investigating whether or not , a group of prokaryotes with the ability to produce oxygen as a by-product of photosynthesis, can be used as a source of renewable energy by converting sunlight into electricity.

Explanation:

Simple cyanobacteria (single-celled organisms that can produce oxygen through photosynthesis) played a key role in providing Earth’s atmosphere and oceans with oxygen

Cyanobacteria or the blue green algae are the only bacteria that contain chlorophyll A, a chemical required for oxygenic photosynthesis, the process which uses carbon dioxide, water and sunlight to produce oxygen and glucose (sugars) for energy

In this process chlorophyll A helps in capturing the energy from sunlight

In addition to chlorophyll A, blue-green algae also contain the pigments phycoerythrin and phycocyanin, which give the bacteria their bluish tint    

All the above characteristics of cyanobacteria can be used as a source of renewable energy by converting sunlight into electricity