ABSTRACT
This chapter examines the general nature of plant hemicellulose and introduces the types, activities, and uses of hemicellulases in biomass conversion technologies. The complex structure of hemicelluloses has dictated an accordingly diverse array of hemicellulases. Generally, each structural feature in hemicellulose has an associated enzyme that can hydrolyze or somehow chemically modify this feature. Hemicelluloses are complex, branched carbohydrate polymers that are formed from different monomeric sugars attached through different linkages. The very complex structure of hemicellulases would require a very large number of enzymes for complete degradation. Nearly every linkage has a specific enzyme responsible for its degradation, and the enzymes generally do not attack linkages other than those for which they are designed. Hemicellulolytic enzyme production is thought to be induced by the presence of low levels of certain oligosaccharides made from enzymes that are produced constitutively and continuously secreted into the environment.
