Until recently, Jatropha Curcas, a tall bush with highly toxic fruit and bark, was mainly used as a hedge plant to keep livestock away from crops.
But amid soaring prices for traditional biofuel feedstock, including palm oil, the nuts from the perennial bush are now being eyed as a possible sustainable alternative.
There is no technical challenge in processing jatropha into biodiesel, said Graham Prince, a spokesman for D1 Oils, a British biodiesel producer. The real commercial challenge is to raise the yield.
Oil palm can yield as much as five metric tons of oil per hectare while, under the best conditions, uncultivated jatropha will yield on average only 1.7 tons, Prince said. On the other hand, he said, "It's still better than rapeseed yields in Europe, at 1.5 tons per hectare and soy, which only yields 0.5 tons."
D1 says that it has identified a variety of the bush from West Africa that, under cultivated conditions, could yield up to 2.7 tons per hectare. "We are at the early stage of commercial development," Prince said. "The first mass multiplication of the seedlings of that higher-yielding variety is being developed now. They will be planted between now and end-2008 on about 50,000 hectares, mainly in northeast India."
The plants mature and start to fruit about two years after planting. D1 plans to harvest and crush the seeds locally and transport the oil abroad.
One of the big advantages of jatropha is that it grows in semi-arid conditions and can be planted on otherwise unproductive land.
For all the buzz around the seeds, Prince warns that governments need to proceed cautiously. "You've got to make sure you're planting this in the right area," he said. "There is no point of having a jatropha bonanza if people start chopping down rainforest to plant, or farmers plant it in areas that are too dry."
The bush needs between 600 milliliters, or 37 cubic inches, and 1,500 milliliters a year of rainfall - ideally 1,000 milliliters, he said. "If it's planted in areas that are too wet or too dry, they might not get any yield at all."
Another problem is that, like coffee, wild jatropha produces fruit and flowers simultaneously. Harvesting therefore needs to be done by hand, but large-scale plantations will ultimately require mechanization.
"We won't be able to develop mechanization until we've done sufficient breeding on jatropha to remove its characteristic of fruiting and flowering at the same time," Prince said.
