CHARACTERISTICS OF FUNGAL CELLULASES

Fungi colonize diverse ecologic niches, yet their cellulases are based on a central theme - exo- and endo-splitting glucanases acting co-operatively and in some instances, synergistically. The characterization of cellulases has proved to be complex. This is due in part to the ill-defined nature of the natural substrates, plus the multiple nature of cellulase components. The rationales for this multiplicity continues to be explored. Cloning studies have shown far less diversity at the genomic level. Additionally, the endo- and exo-splitting glucanases have been shown to be comprised of a tripartite structure with both enzyme forms containing a cellulose binding site, hinge region and catalytic domain. Oxidative enzymes (cellobios quinone oxido-reductase, cellobiose oxidase and lactonase) though minor in quantitative terms, may have important roles in the regulation/initiation of cellulase synthesis per se.