A microbial fuel cell, about the size of a teacup, uses bacteria to turn corn stover into electricity. Click photo for larger image.

When it comes to the corn plant, Penn State University has proven there's as much pop in the plant as there is in the corn.

A Penn State scientist has developed technology that uses corn stover -- cornstalks, leaves and other leftovers after the corn is picked -- to produce electricity.

All it requires is engineering expertise and some hungry bacteria.

Dr. Bruce E. Logan, professor of environmental engineering and director of the Penn State Hydrogen Energy Center & Engineering Environmental Institute, announced development of the teacup-size fuel cell in the July 19 edition of Energy & Fuels, an American Chemical Society journal.

He, Yi Zuo and Pin-Ching Maness in Penn State's Department of Civil and Environmental Engineering, completed the research and produced the study under grants from the National Science Foundation and the U.S. Department of Agriculture.

The fuel cell uses a common bacteria to turn corn stover, under pressure, immediately into an electrical current. The bacteria digests plant sugars, producing protons and electrons, the latter of which are captured and turned into an electrical current.

"We are breaking up sugar molecules and making electricity," Dr. Logan said.

To date, the research team has created a fuel cell that produces enough watts of electricity to run a small fan. The hope is to scale up the technology to produce large energy supplies at an affordable price, he said.

Microbial fuel cells have been the subject of research and speculation for decades because they produce electricity without any auxiliary power source and can be used in remote locations, even on the ocean floor.

"All you need is a cup of microbes. Give them food and let it go," Dr. Logan said. "And it's all running at room temperature."

Dr. Derek Lovley, a distinguished professor in the Department of Microbiology at University of Massachusetts in Amherst, is focusing his research on how bacteria produce electrons.

"Fuel cells have what we call the 'Eveready Bunny effect,' " he said. "It just keeps going as long as there is fuel available to be converted into electricity."

Fuels include corn stover, sewage or ocean sediment.

To date, fuel cells fueled by sediment on the ocean floor are being used to power monitors, Dr. Lovley said.

Dr. Logan's team, he said, is focusing on the engineering side of fuel cells, while he's focusing on microbial research.

"I think their main contribution has been in changing design parameters to improve the power output -- how can it be built to increase power?" he said of Dr. Logan's research.

There's even hope someday that a fuel cell can be developed to use blood sugar to power pacemakers or other in-body health devices.

Dr. Logan said his team focused on corn stover because so much is produced in agriculture. Penn State's research proves that corn stover is efficient in producing electricity.

"The potential volume of corn stover is enormous," he said. "We're not just talking about a little bit of waste, but a kind of material that people could be using in transportation."

But reaching that level will take a few more breakthroughs.

"This is right out of the lab, but we know we can do it," Dr. Logan said. "We're refining the fuel cell. Work is continuing to increase the efficiencies of the electrical system and making it affordable."

In 2004, Dr. Logan's team announced the first fuel cell that used bacteria to turn sewage into electricity. The bacteria was the type already available in sewage.

The technology transforms 78 percent of sewage flowing into a treatment plant into electricity, he said.

At the time, he expressed optimism the technology could help reduce the $25 billion annual cost of wastewater treatment in the United States and provide sanitation technology that can be used worldwide.

He said a demonstration project using a refrigerator-size fuel cell will be installed in a sewage treatment plant within two years to show the potential of using sewage to produce electricity. In time, he said, fuel-cell technology could produce enough electricity to power the entire treatment plant and create surplus energy.

That could lead to reductions in the nation's use of oil and fossil fuels, he said.

Five percent of electricity in the United States already is used to treat, pump and process water and sewage, he said.

Although the technology is in its infancy, Dr. Lovley said another breakthrough or two will make the technology feasible for various applications.

"It's a fun time to be working on something like this," he said. "With oil prices rising, it will get more interest."

Dr. Bruce Logan, here at the lab on Penn State's main campus, said he aims to install a demonstration project in a sewage treatment plant using a refrigerator-size fuel cell within two years to show the potential of using sewage to produce electricity.