Washington, Aug 26 - Juice from rejected watermelons is a potential source of biofuel as it can be fermented into ethanol, says a new study.

Wayne Fish worked with researchers at the US Department of Agriculture (USDA) lab in Lane, Oklahoma, to evaluate the biofuel potential of juice from 'cull' watermelons -- those not sold due to cosmetic imperfections.

'About 20 percent of each annual watermelon crop is left in the field because of surface blemishes or because they are misshapen,' said Fish.

'We've shown that the juice of these melons is a source of readily fermentable sugars, representing a heretofore untapped feedstock for ethanol biofuel production,' said Fish.