Fuels and chemicals from biomass

Increasing energy consumption, coupled with decreased petroleum supplies, has made development of alternate energy sources a pressing national problem. One of the alternatives presently being examined is obtaining fuels from biomass. Biomass, which is a form of stored solar energy (sunlight having been converted by photosynthesis to cellulosic materials) is an abundant, renewable, domestically available energy resource. Although techniques of converting cellulosic materials in biomass to sugars and then to alcohol have been available for over one hundred years, it is only recently that the efficiency of this type of process has been improved to the point where the economics look potentially attractive. A major processing step responsible for this improvement is the conversion of cellulose to glucose in high yield. While the yield of sugars from cellulose was on the order of 50% previously, this has been improved to 90% or greater by a process in which cellulosic material is solvent-pretreated to make it readily accessible to hydrolysis to sugars by either acid or enzyme. This approach to hydrolysis, together with the fermentation of the resulting sugars to alcohol, is known as the Purdue Process. This process is discussed in the context of prior work done in this field.