Forget chip fat, sugar cane or rapeseed oil -- the latest source of biofuel could be watermelons. Scientists have discovered that the fruit is a great source of sugar that can be readily distilled   into alcohol to power cars and farm machinery. And sellers reject 360,000 tons of "substandard" fruit every year in America alone which could be used as an economical way to make fuel. The waste from US growers could produce nearly two million gallons (nine million litres) of biofuel per year. In the study, researchers at the United States Department of Agriculture set out to determine the biofuel potential of juice from rejected watermelons --those not sold due to imperfections, and currently ploughed back into the field. About a fifth of each yearly watermelon crop is left in the field because of surface blemishes   or because they are misshapen. Dr. Wayne Fish, who led the team, found that 50 percent of the fruit was fermentable   into alcohol which could provide valuable fuel. "We've shown that the juice of these watermelons is a source of readily fermentable sugars, representing an unexploited raw material for alcohol biofuel production," he said. The study, published in the journal Biotechnology for Biofuels, discovered that watermelons could produce around 20 gallons of fuel per acre from fruit that otherwise would go to waste. Production of biofuels has been targeted by Western governments as a way to support renewable energy targets. The European Union has a target for 2010 that 5.75 percent of transport fuels should come from biological sources, but the target is unlikely to be met. The British government's Renewable Transport Fuel Obligation requires five percent of the fuel sold at the pump by 2010 to be biofuel. The passage mainly tells us    _   .
watermelon juice will be the largest source of renewable energy the advantages of fuel made from watermelons Western countries aim at producing biofuels watermelons could be used to make fuel