A Florida start-up formed in 2006 plans to commercialize technology developed by the US Department of Agriculture in the 1990s to produce ethanol from citrus waste. (Earlier post.) Citrus waste is rich in pectin, cellulose and hemicellusic polysaccharides, which can be hydrolyzed into sugars and fermented into ethanol.
Citrus Energy is seeking to raise $10 million to build an initial 4 million gallon per year ethanol plant. USDA researchers have estimated that the state has sufficient citrus waste to produce 80 million gallons of ethanol per year.
In addition to ethanol, the process produces limonene and cattle feed. Efficient fermentation requires the reduction of limonene—a terpene-based solvent which is the fruit’s natural defense against bacteria, viruses, and molds—by approximately 90%, according to the company.
For cattle feed, the solids (equivalent to wet distillers’ grains from corn) recovered from the distillation system after ethanol stripping will be delivered to the existing feedmill for drying.
Citrus Energy notes that the 5 million tons of citrus waste produced annually from Florida’s 100 million citrus trees is available on a continuous basis for 8 months a year with no transportation costs to ethanol plants co-located with citrus producers. Existing road and rail transportation systems servicing the citrus plant would take the ethanol to market.
(A hat-tip to The Fueling Station!)