Darpa's Adventures in Trash

Take plastic wrap. Add tap water. Get fuel.

That's the idea behind Darpa-funded research, to turn what would have been waste into diesel that can be used to run Humvees, tanks, and Bradleys. And if it works out as planned, the plastic conversion could solve two of the armed force's most vexing logistical problems.

You see, military bases today produce an enormous amount of trash -- more than 7 pounds per day, per soldier. A big stinkin' pile of "personnel, fuel, and critical transport equipment are needed to support the removal and disposal" of that waste, Darpa notes. What's more, making those transportation runs is ridiculously expensive; the Office of Naval Research figures fuel on the battlefield costs up to $400 per gallon.

So Darpa has given Dr. Richard Gross, a professor of chemistry at Brooklyn's Polytechnic University, more than $2 million to morph "plant oils, of the kind already used to make biodiesel, into 'bioplastic.' The plastics can be films or rigid, as are commonly found in food packaging. Then he uses a naturally occurring enzyme to break down the plastic into fuel," the *Times *reports.

*“It works in very mild conditions, lukewarm tap water,” he said. The enzyme, cutinase, is present in nature, made by parasites to eat through the shiny surfaces of tree leaves, so the parasite can suck nutrients out of the inner parts. *

A gene-splicing company, DNA
2.0, has taken some of the DNA from that parasite and spliced it into an e. coli bacterium, to mass produce the enzyme. The e. coli was chosen because it reproduces more readily than the original parasite.

Conversion begins with shredding the plastic. An office paper shredder will do,
Dr. Gross said. Then the shreds are immersed in water with a small amount of the enzyme. In three days to five days, the process is complete, and the biodiesel floats to the top.

__ UPDATE__: Here's a good, if slightly old, rundown of the military's eco-friendly efforts.

(High five: Nicholas Weaver)