Turning Watermelon Into Energy

Watermelons as fuel give you some food for thought. (Photo: Mike Mozart [CC BY 2.0]/Flickr)

Watermelon farmers have to resign themselves to leaving 20-40 percent of their crop in the fields to rot every year because of superficial flaws -- misshapen fruit, peck marks, or any other imperfection that would turn off your average American grocery store shopper. That's a lot of wasted fruit, estimated at 360,000 tons (that's 720 million pounds!) every year. Watermelons take a lot of water to grow -- losing 20-40 percent of every crop is an expensive exercise in waste for both farmers and water tables.

A new study in the journal Biotechnology for Biofuels has found that those wasted watermelons could be turned into up to 2.5 million gallons of ethanol. It turns out that watermelon juice is a great base to make ethanol from -- it's full of sugar and yeast-friendly amino acids.

It's also a great fuelstock because it is food that's not being diverted from the food stream. When a farmer grows an acre of corn and chooses to sell it to an ethanol plant, that's food being taken off our tables and out of our mouths. Using wasted watermelon nicely sidesteps that problem because if the fruit wasn't used for ethanol, it'd just end up rotting on the vine. 2.5 million gallons isn't a huge amount in the scheme of things (we use 390 millions of gas per day), but it's a good piece of low-hanging fruit and could help provide a business and technological model for other kinds of agricultural waste.

Source: [Michael Reilly, Discovery News]