By putting bacteria to work, a new bioreactor produces hydrogen hundreds of times as fast as previous prototypes.
In a microbial fuel cell, bacteria break down organic matter, releasing electrons and protons into a solution. The protons migrate through a membrane, while the electrons enter a cathode and pass through a circuit that delivers them to the protons on the other side. There, protons—ionized hydrogen—and electrons react with oxygen to produce water, at the same time generating a voltage that keeps the electrons flowing, so the device produces a small amount of electric power (SN: 2/4/06, p. 72).