June 4, 2009

Watermelons can be tapped for ethanol, studies show

LANE, Okla.—Watermelons are a favorite summertime treat, especially at picnics and Fourth of July festivities. But this Independence Day favorite could become even more of a patriotic commodity.

Studies by the U.S. Department of Agriculture’s Agricultural Research Service show that simple sugars in watermelon juice can be made into ethanol. In 2007, U.S. growers harvested 4 billion pounds of watermelon for fresh and cut-fruit markets. According to ARS, around 800 million pounds, about 20 percent of the total crop, were left in the fields because of external blemishes or deformities.

Such melons could be used for ethanol, which already is produced by using cane crops like corn and sugarcane. The watermelon study reflects ARS efforts to diversify America’s array of biofuel crops that can diminish the reliance on petroleum, especially from foreign sources.

On average, a 20-pound watermelon will yield about 1.4 pounds of sugar from the flesh and rind, from which about seven-tenths of a pound of ethanol can be derived.

Scientists also are examining annual ryegrass, sorghum and other crops that could be rotated with watermelons to furnish ethanol processing plants with a year-round supply.

Contact Jan Suszkiw, ARS branch public affairs specialist, at 301-504-1630.