Watermelons: The Newest Renewable Energy Source

This has nothing to do with space or astronomy, but is perhaps one of the juiciest pieces of new I have ever read. Could we one day be driving cars fueled by watermelons? Researchers say that watermelon juice can be a valuable source of biofuel, as it can be efficiently fermented into ethanol. But have no fear, using watermelons for biofuel wouldn’t cut into the amount of watermelons available for the public to eat. This research evaluated the biofuel potential of juice from ‘cull’ watermelons – those not sold due to cosmetic imperfections, and currently ploughed back into the field. Wayne Fish from the US Department of Agriculture said, “About 20% of each annual watermelon crop is left in the field because of surface blemishes or because they are misshapen. 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.”

The researchers conclude that at a “production ratio of ~0.4 g ethanol/g sugar, as measured in this study, approximately 220 L/ha of ethanol would be produced from cull watermelons.”

As well as using the juice for ethanol production, either directly or as a diluent for other biofuel crops, Fish suggests that it can be a source of lycopene and L-citrulline, two ‘nutraeuticals’ for which enough demand currently exists to make extraction economically worthwhile. After these compounds have been removed from the ‘cull’ juice, it can still be fermented into ethanol.

Read the “juicy” paper here.