One of the essential elements in the economical and efficient production of cellulosic biofuels is the development of biorefineries. Similar in concept to traditional petroleum refineries, biorefineries convert various types of biomass feedstock into marketable chemicals, fuels, and products. By taking advantage of the differences in biomass components and intermediates, biorefineries maximize the value derived from the feedstock by producing high-value, low-volume products, enhancing profitability; and low-value, high-volume fuels to meet the nation's energy needs. Biochemical processing produces such co-products as succinic and acetic acids (among the ingredients for biobased polymers) and other materials. Products produced from the biorefineries can be used by the transportation, energy, chemical, and power industries.