A Renewable Energy Source: Tiny Microbes (IMAGE) Arizona State University Caption Tiny photosynthetic bacteria, called cyanobacteria, less than the size of a pollen grain, can be optimized to produce a renewable source of biodiesel. Shown is an electron microscope (EM) image of cyanobacteria. That fast-growing microbes divide every 20-40 minutes under optimal conditions. Credit Arizona State University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.