Watermelons-Juicy and Apparently Good for Biofuels

A USDA lab claims watermelon juice may be a hot source of future fuel

Watermelons may be the perfect food for a lazy summer afternoon, but do they also hold what your engine needs to get it running? The USDA's South Central Agricultural Research Lab believes so. The research lab just wrapped up a new study, published in the journal Biotechnology for Biofuels, which examined the viability of watermelon as a biofuel feedstock.

According to the researchers, watermelons are a near perfect biofuel crop for temperate climates. At the bottom of the USDA researchers' plan is harvesting waste melons. According to the research, "About 20% of each annual watermelon crop is left in the field because of surface blemishes or because they are misshapen; currently these are lost to growers as a source of revenue."

The USDA instead proposes to harvest these malformed melons and put them to good use as a biofuel feedstock. The USDA researchers believe a waste stream of 500 L/t (liters per ton) could be feasible in the near future. With typical yields at about 20,000 to 40,000 pounds per acre on successful farms, this equates to roughly 10 to 20 liters per acre. With 57,186 hectares devoted to watermelon growing in 2004, this equates to roughly 1.4-2.8 million liters annually.

The USDA researchers believe that growing production of the fruit will lead to increasing yields of waste melons. Packed with so-called "neutraceuticals" (healthful compounds from natural sources) -- lycopene (also found in tomatoes) and L-citrulline -- demand for the melons is growing. The USDA believes that the combination of extracting financially valuable nutrients from the melons, selling them for food, and using the leftovers for fuel feedstock, will both help farmers and the biofuel industry.

The melons themselves have approximately 7-10 percent directly fermentable sugars by weight/volume. They also have 15 to 35 umol/ml of free amino acids, which could also be used to produce biofuels. By using yeast and controlling the pH, researchers were able to raise the fermentation rates to 35 percent of the w/v. Returning to our original estimates of the liters per year, give the USDA's statements, this would make for approximately 500,000 to 1 million liters of ethanol per year.

The study looked at producing ethanol from the melons. In the U.S. most ethanol is produced from corn grown specifically for that purpose (not waste). The melon juice could also prove an ample feedstock for other types of biofuels, such as biodiesel, or biogasoline.


Source:dailytech