Big Energy From a Small Source
Scientists at the University of California, Berkeley, and the University of Pennsylvania think that such methods of creating hydrogen could become practical within 10 years. They also see potential in the fact that some microbes generate minute amounts of electricity as they break down organic matter, leading to the possibility of "microbial fuel cells" that run on virtually any biodegradable material.
The present challenge appears to be getting enough yield out of the microbes. Researchers are experimenting with ways to make bacteria more efficient at generating energy, and to optimize the conditions for these bacteria.