Actual Microbial Electrolysis Cell (IMAGE) U.S. National Science Foundation Caption A microbial electrolysis cell (MEC) shown with the power source used to augment the voltage produced by the bacteria. Bacteria grow in the anode chamber, forming a biofilm on graphite granules, while hydrogen gas is released at the cathode and bubbles up and into the tube on top of the reactor. Credit Photograph by Shaoan Cheng, Penn 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.