For many, the hope for biomass to fuel our cars and planes lies in genetically engineered super plants. But such plants, let alone the infrastructure to process them, are well on the horizon. For now, all eyes are on nature's miracles—and everyone is buzzing about a plant called jatropha.

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Jatropha is a Central American weed that grows in warm climates such as Africa and India. Farmers in Africa have primarily used it as a natural fence, planting it around food crops, because animals don't like the smell, but it also prevents soil erosion, and requires little in the way of water and fertilizer.

The main reason for the increased attention it is drawing is that compared to other fuel plants like switch grass and algae, jatropha contains more oil. One acre can produce about 200 gal of biodiesel per year, compared to around 90 gal for canola oil and 55 gal for soy, says Ihab Farag, professor of chemical engineering at the University of New Hampshire, who researches jatropha. Also, jatropha is not a food crop; so planting it for fuel will not spark food shortages or drive up food prices. And jatropha can be grown on arid land where food cannot grow.

Jatropha could help increase incomes of farmers, who could sell the seeds, advocates of the plant say. Since the weed also improves soil and acts as a natural fence when interspersed with food crops, it increases crop yield by as much as 20 percent over four to five years, says Hugo Verkuijl, CEO of Dutch company Mali Biocarburant. Verkuijl is working with the Malian government and farmers to cultivate jatropha plants, and this fall, the company will begin producing 600,000 liters (about 156,000 gal) of biodiesel per year, he says.

These farmers sell the jatropha seeds to the company for biodiesel production, and they also hold shares in the company. In order to facilitate the process of shucking the seeds, the farmers use a tool developed by Popular Mechanics Breakthrough Award winner Jock Brandis to remove the jatropha seeds from their shells. The universal nut sheller can husk around 150 kilograms (about 331 pounds) of jatropha an hour, saving farmers the time-consuming task of hand-shelling the seeds, one by one. So far, fuel made from jatropha has been used to run trains in India and was even in the tank of a Boeing 737-800 flying for Continental airlines.

Despite its potential, there are still problems that will have to be worked out before jatropha is a viable biofuel. One is that jatropha contains the toxin phorbol ester, and if its seeds are eaten, they can cause vomiting and even death. Jonathan Gressel, professor of plant sciences at the Weizmann Institute of Science in Israel, says that because of the phorbol esters, there should be more research on the health effects of handling jatropha oil.

Jatropha also needs to be cultivated. Since it is a wild plant, its seeds do not ripen at the same time, so a field of jatropha cannot all be harvested at once. University of California–Davis agronomist Sham Goyal says they are trying to solve that problem through breeding and genetic modification. Once jatropha is cultivated, technology will need to be developed to mechanically harvest it. But, Goyal says, this is still years away. "It's biology," he says. "It takes its own time." —Monica Heger