Japanese team cracks into biofuel with crab shells
TAKURO KUSASHIO, Nikkei staff writer
OSAKA -- Researchers at Kobe University say they have found a possible way to turn bits of crustaceans and insects into ethanol for about the same cost as producing the fuel from corn.
Chitin, the stuff that gives the exoskeletons of such creatures as crabs and beetles their toughness, consists of chains of sugar and nitrogen molecules. Also common in the cell walls of fungi and bacteria, it can be chemically broken down into a variety of sugars. Chitin is regarded as the second-most-abundant natural polymer on Earth, after the plant fiber cellulose.
Kentaro Inokuma and his research associates discovered among the yeasts that break down xylose, a kind of sugar, one that proved effective at fermenting the chitin-derived sugars to produce ethanol. It works so well that it exceeds the theoretical 70% limit on conversion efficiency, according to the team.
The group reckons that the yeast can be genetically modified to achieve 90% efficiency. At that rate, ethanol would cost 50 yen (44 cents) per liter or less to produce by this method -- about the same as with corn, sugar cane or other more commonly used biomass.
Inokuma's team continues working to improve on its idea, using raw materials from seafood-processing plants and other sources. Given enough chitin, producing ethanol in this way can be commercially competitive even amid the current low crude oil prices, the scientists believe.
Making biofuel from corn or sugar cane can drive up food prices, so researchers have been experimenting with inedible feedstocks, such as waste wood, grass and algae. Chitin-containing biomass could provide another abundant alternative.