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Biofuel Cells May Turn Cockroaches into Cyborgs

The sugars in a cockroach's belly have been harnessed by a fuel cell and converted into electricity, a big step toward turning insects into cyborgs, scientists are reporting.

Once miniaturized to the point that the fuel cells are non-invasive to the cockroaches, they can be implanted to power sensors or recording devices, for example.

A rechargeable battery inserted along with the so-called biofuel cell would store the trickle of energy it generates, explained Daniel Scherson, a chemist at Case Western Reserve University in Cleveland.

"If you want to be futuristic, one may use the energy stored to try to control the neurological system of the cockroach and then you might be able to (control) the cockroach (with) a joystick," he told me.

Yes, in the future, that nasty cockroach scurrying across the kitchen floor might actually be a spy set loose by a nosy neighbor, or the CIA.

Sugar Fuel

The power supply for this fuel cell is food the cockroaches eat, avoiding the need for devices that harness electricity from movement, such as shoes that turn mechanical energy into electricity.

The fuel cell devised by Scherson's team uses a cascade of reactions by enzymes to convert energy stored as sugars into electricity.

The first enzyme breaks down the sugar trehalose, which cockroaches constantly produce from their food, into two simpler sugars.

A second enzyme oxidizes the simple sugars, releasing electrons that "can then be funneled together to electrodes where they are captured and delivered to oxygen," Scherson explained.

The team first tested the system on trehalose solutions, then inserted prototype electrodes into the belly of a female cockroach. It worked.

The biofuel cell produced a trickle of electricity — 0.2 volts. Full details on the system are published online in the Journal of the American Chemical Society.

Intermittent Tasks

Since the researchers don't want to load down a bug with a heavy fuel cell and impair its ability to move, they envision storing the energy up in a battery, then using that energy to perform tasks such as power sensors.

One potential application is to equip social insects such as bees or ants with sensors tuned to detect a dangerous chemical and send them out to the environment.

Periodically, the sensor would turn on and broadcast its finding, shutting down between broadcasts to allow the battery time to recharge.

Operating at 0.2 volts is enough power to send a message a few inches, according to Scherson, far enough that a message could be sent down a line of ants spying on a top-secret meeting in a park.

To get there, the researchers need to shrink their fuel cells so they can be fully implanted, find long-lasting materials to make them with so they don't breakdown inside the bugs' bodies, and build the signal transmitters.

All of this is in the realm of possibility, noted Scherson.

"People do wonderful things with circuitry."

George Williams,
General Manager - Staff Entomologist

Pest Control, RI, Pest Control, MA 

Termites May Help Solve Fuel Crisis

One of the peskiest household pests, while disastrous to homes, could prove to be a boon for cars, according to a Purdue University study.

Mike Scharf, the Chair in Molecular Physiology and Urban Entomology, said his laboratory has discovered a cocktail of enzymes from the guts of termites that may be better at getting around the barriers that inhibit fuel production from woody biomass. The Scharf Laboratory found that enzymes in termite guts are instrumental in the insects' ability to break down the wood they eat.

The findings, published in the early online version of the journal PLoS One, are the first to measure the sugar output from enzymes created by the termites themselves and the output from symbionts, small protozoa that live in termite guts and aid in digestion of woody material.

"For the most part, people have overlooked the host termite as a source of enzymes that could be used in the production of biofuels. For a long time it was thought that the symbionts were solely responsible for digestion," Scharf said. "Certainly the symbionts do a lot, but what we've shown is that the host produces enzymes that work in synergy with the enzymes produced by those symbionts. When you combine the functions of the host enzymes with the symbionts, it's like one plus one equals four."

Scharf and his research partners separated the termite guts, testing portions that did and did not contain symbionts on sawdust to measure the sugars created.

Once the enzymes were identified, Scharf and his team worked with Chesapeake Perl, a protein production company in Maryland, to create synthetic versions. The genes responsible for creating the enzymes were inserted into a virus and fed to caterpillars, which then produce large amounts of the enzymes. Tests showed that the synthetic versions of the host termite enzymes also were very effective at releasing sugar from the biomass.

They found that the three synthetic enzymes function on different parts of the biomass.

Two enzymes are responsible for the release of glucose and pentose, two different sugars. The other enzyme breaks down lignin, the rigid compound that makes up plant cell walls.

Lignin is one of the most significant barriers that blocks the access to sugars contained in biomass. Scharf said it's possible that the enzymes derived from termites and their symbionts, as well as synthetic versions, could be more effective at removing that lignin barrier.

Sugars from plant material are essential to creating biofuels. Those sugars are fermented to make products such as ethanol.

"We've found a cocktail of enzymes that create sugars from wood," Scharf said. "We were also able to see for the first time that the host and the symbionts can synergistically produce these sugars."

Next, Scharf said his laboratory and collaborators would work on identifying the symbiont enzymes that could be combined with termite enzymes to release the greatest amount of sugars from woody material. Combining those enzymes would increase the amount of biofuel that should be available from biomass.

The U.S. Department of Energy and Chesapeake Perl funded the research.

George Williams,
General Manager - Staff Entomologist

Pest Control, RI, Pest Control, MA