The concept of converting cellulose from biomass into an end product of alcohol fuel is relatively simple. Using cellulase enzymes, cellulose, the major substance in plant fiber, can be converted into glucose. This glucose is then fermented by yeast or other microorganisms into alcohol. The fermentation process is similar to that used in fermenting beer and wine. The resultant product, depending on the organisms employed, is one of several types of alcohol fuels. In other countries where gasoline prices are higher, ethanol from biomass already appears to be an attractive alternative.