Watermelon Waste Proposed for Biofuel Production
photo: Keith McDuffee via flickr
You've probably seen all sorts of things proposed as good feedstocks for biofuel, but watermelons? That's what researchers writing in the journal Biotechnology for Biofuels are saying (hat tip to Mongabay). They probably wouldn't work, without effort, as the sole feedstock, but could be used with other feedstocks:The idea isn't to use watermelons growing specifically for biofuels, but rather the wasted watermelons -- specifically the estimated 20% of the annual watermelon crop which isn't suitable for sale because of blemishes or unusual shapes. (Whether those watermelons really couldn't be put to better use, in some nutritional sense, wasn't discussed...)
Here's the other reason why watermelons should be considered:
the neutraceutical value of lycopene and L-citrulline obtained from watermelon is at a threshold whereby watermelon could serve as starting material to extract and manufacture these products. Processing of watermelons to produce lycopene and L-citrulline, yields a waste stream of watermelon juice at the rate of over 500 L/t of watermelons. Since watermelon juice contains 7 to 10% (w/v) directly fermentable sugars and 15 to 35 umol/ml of free amino acids, its potential as feedstock, diluent, and nitrogen supplement was investigated in fermentations to produce bioethanol.
After tests, the researchers concluded that watermelon juice would have to be concentrated 2.5-3 times if it was to be used as the sole biofuel feedstock, but watermelon juice could easily be integrated with other feedstocks "as diluent, supplemental feedstock, and nitrogen supplement."
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