Fruit could make 'powerful fuel'
Written on 3:41 PM by Unknown
Scientitsts in the United States say they have broken new ground in biofuels, transforming plant sugar into a liquid fuel that packs 40% more energy than ethanol and appears to have fewer of its drawbacks. The sugar found in fruit such as apples and oranges can be converted into a new type of low carbon fuel for cars.
Fructose — the sugar found in fruit such as apples and oranges can be converted into a new type of low carbon fuel for cars. Ethanol (ethyl alcohol) is currently the only car fuel made in large quantities from biomass, under fast-expanding initiatives to wean industrialized economies from dirty, costly oil.
Biomass sources such as corn, sugarcane and other plants are rich in potential energy, in the form of large chains of carbohydrates. In their plant form, these long sugary molecules comprise six carbon atoms and six oxygen atoms.
But car engines like a leaner form of carbohydrate molecule — one with between five and 15 carbon atoms and with very little oxygen.
Most ethanol facilities harness biology, using enzymes to break down starch and cellulose to glucose, which is then fermented by a common yeast, Saccharomyces cerevisiae, to produce ethanol and carbon dioxide.
But the process takes days and the fuel still has relatively high levels of oxygen, which reduces its energy density, makes it evaporate readily and leaves it liable to water contamination by absorbing atmospheric humidity.
The process is renewable and environmentally-friendlier than fossils but not completely clean. Energy has to be used to harvest and process the biomass, and this makes biofuels carbon-positive, not carbon-neutral.
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