Biofuel cells provide long-lasting power, potential military uses
by Brian R. Hook

Biofuel cells, using enzymes to trigger chemical reactions to produce electricity for long periods, might soon power remote sensors for the United States military.

Akermin Inc., a biocatalyst technologies company, has developed a biofuel cell in the lab that has generated power continuously for more than three years. This new technology lasts two to four times longer than high-performance lithium batteries.

The biofuel cell technology, first invented at Saint Louis University, uses enzymes that replace the metal catalyst in conventional cathodes to create electricity.

“We employ naturally occurring enzymes that we immobilize in our proprietary polymer that stabilizes them for the reaction condition of the fuel cell,” says Nick Akers, founder and director of business development of the Creve Coeur, Missouri-based firm.

“Other biofuel cell work has demonstrated enzyme operating times of days to weeks, whereas our unique immobilization technology has demonstrated over three years, and counting, enzyme stability for the reaction to generate electricity from alcohol.”

Enzymes, which have been used as catalysts for years in a variety of industrial processes, react with the fuel at the electrode’s surface to generate electricity. However, enzymes usually exhibit a short life span when exposed to harsh chemical environments and high temperatures. Akermin’s stabilization technology solves this problem.

Akermin developed an enzyme stabilization technology using a protective polymer structure to extend the operating life of the biofuel cell. The technology immobilizes the enzyme so it can be attached to a support structure that does not inhibit enzyme contact with the substrate, yet protects the enzyme from harsh elements.

“The key barrier to commercial viability has been the instability of enzymes in a fuel cell,” says Akers, co-inventor of the stabilized enzyme biocatalyst system.

By immobilizing the enzyme at an electrode surface with Akermin’s polymer, the enzyme activity has been retained to continuously oxidize the fuel for over three years. Without the stabilizing technology the enzyme remained active for only hours to days.

Biofuel cells differ from traditional fuel cells. With biofuel cells, the catalyst uses enzymes to directly react with the fuel, rather than using precious metals. The enzymes are naturally occurring and are renewable. Enzymes are also less expensive than metals.

Akermin is targeting the wireless sensor market for both industrial and military uses, where customers seek a low-wattage, long-lasting energy source for unattended devices. Examples include sensor devices for perimeter and border security. Akermin also hopes to enhance the value of food, pharmaceutical and chemical production.

The company is in the process of sampling an advanced prototype with qualified customers. Akermin also received an $860,000 contract in June from the U.S. Army’s Communications-Electronics Research Development and Engineering Center in Aberdeen Proving Ground, Maryland. The award is for the development of a stabilized enzyme biofuel cell for use in unattended ground sensor applications for the military.

“Biofuel cell technology has several advantages for unattended ground sensor applications,” says Elizabeth Ferry, fuel cell team leader at CERDEC. In addition to the long run-time and using enzyme catalysts rather than precious metals, the technology is non-toxic, which allows the sensor to be disposable and left in place without recovery.

“The use of unattended sensor technologies for remote battlefield applications has greatly increased,” Ferry says. “Unattended ground sensors provide valuable information to the soldier and an increased level of situational awareness on the battlefield.”

The unattended sensors can exist in various sizes and forms, contain several sensor technologies and can report information on or about different types of targets, Ferry says. Plus, the longer these devices can be powered without the need to return to change the battery or power source, the lower the risk is to military personnel.

Akermin is hoping for further military contracts to produce more stabilized enzyme biofuel cells. CERDEC will consider more contracts once the first 12-month process is completed. “If Akermin is successful, we hope to complete a significant amount of government testing and identify a suitable path forward,” Ferry says.

Akermin has raised almost $9 million since its start in 2004. Barry Blackwell, one of the first investors in the firm as part of the St. Louis Arch Angels Network, has been on the firm’s board since inception. Members of the Arch Angels provide financing for early-stage companies based in the St. Louis region with high growth potential.

Blackwell, who is now Akermin’s president and chief executive officer, says further financing is needed to commercialize the company’s technology. He hopes to have commercial products available for the sensor market by late next year.

“We are able to differentiate ourselves for the product runtime versus alternative power sources, whether it is incumbent batteries or other fuel cells,” Blackwell says. “We continue to expand our development opportunities with our mobilization technology.“

Blackwell says that Akermin plans to build upon its mobilization technology, expanding beyond biofuel cells in the future. He says he hopes to make more announcements about further opportunities in the fourth quarter of this year.

Chrysalix Energy Venture Capital, a venture capital firm in Vancouver that focuses on clean-energy technology, invested in Akermin in 2005. “We felt Akermin had a very interesting platform technology,” says Mike Walkinshaw, managing director.

“Our experience in clean energy technologies indicated that the enzyme encapsulation technology will dramatically improve the performance of enzymes in a variety of functions. Lifetime of the enzyme in the application is the key variable and it is where Akermin has shown a significant advantage over comparable technologies.”