Ethanol is commonly referred to as bioethanol when it is manufactured from agricultural sources, for example, corn or wood. The production of bioethanol from biomass is a proven industrial process for producing fuel from a renewable source. It can be directly mixed with gasoline (petrol) and used in today's automotive vehicles, or used as a fuel for the generation of electricity. Currently, there are two types of blends of ethanol and gasoline on the market: E10, which is 10% ethanol and 90% gasoline, and E85, which is 85% ethanol and 15% gasoline (E85). In the United States, many states currently mandate E10. It is generally accepted that bioethanol gives a 70% carbon dioxide reduction (compared to unblended gasoline), which means 7% in an E10 blend or 50% in an E85 blend. Increased bioethanol usage could reduce U.S. greenhouse gas emissions to 1.7 billion tons/year (22% of the 2002 emissions). Recent investigations have established that polysaccharides in biomass can be hydrolyzed enzymatically into glucose sugar that can be fermented to bioethanol. Fungi, including yeast, are a key source for some of the industrially important enzymes used in this process.