Global warming is a hot environmental issue. How do we reduce our use of fossil fuels, which add to the greenhouse effect? One alternative to the petrol used in motor vehicles is fuel ethanol. To produce ethanol from grains such as corn (maize), wheat, barley, rye or sorghum, an enzymatic treatment is required. Enzymes break down the starch into fermentable sugars. This is where Novozymes comes in. Novozymes has become a major supplier of enzymes to fuel ethanol manufacturers around the world and has developed special enzymes for this purpose.
The vast majority of ethanol is currently used as an oxygenate or octane booster in blends of around 10% with petrol. In the USA, where the production of fuel ethanol is booming, more than 1% of the total fuel used annually in vehicles consists of ethanol. There are reports of about eight to ten new fuel ethanol plants being opened every year, primarily in the Midwest.
When ethanol burns, it simply produces water and carbon dioxide. Supporters of ethanol point to the lower emissions of the greenhouse gas carbon dioxide compared to petrol. A blend of petrol and 10% ethanol emits 5% less carbon dioxide than ordinary petrol. Furthermore, the crops used to make ethanol absorb as much carbon dioxide from the atmosphere as is released when the ethanol is combusted. Ethanol also offers a chance to phase out the petrol additive methyl tert-butyl ether (MTBE), a harmful chemical.
In the USA, fuel ethanol is currently made from corn, and 7% of US corn production is used in its manufacture. For liquefaction, Novozymes' Liquozyme® SC is the market leader. The other main enzyme used in the USA is the glucoamylase Spirizyme® Fuel. Wheat and barley are being converted into fuel with these and additional viscosity-reducing enzymes in Europe and Australia, while China is using mostly corn in brand new fuel ethanol plants.
Today, grains rich in starch are being converted into fuel ethanol, but in future cellulose will also be used. Cellulose is the most abundant organic material on Earth, and biomass such as agricultural residues could become an unlimited source of energy. One of the technical barriers is how to convert cellulose into glucose, but Novozymes has already come a long way in developing cellulases that can do this economically. If the technology becomes commercial, it could spawn a whole new industry for converting biomass into fuel ethanol and other valuable products. Local mills would need to be built near the sources of biomass. These are exciting possibilities in a world suffering from global warming and a dependence on finite supplies of oil for its fuel needs.