ABSTRACT
Chitin, the (1-4)-j3-linked homopolymer of N-acetyl-D-glucosamine, is one of the most abundant polymers in the biosphere, and chitinolytic enzymes are found among all kingdoms, i.e., protista, bacteria, fungi, plants, invertebrates and vertebrates, including humans. Enzymatic degradation of chitin is involved in many biological processes, such as autolysis, morphogenesis and nutrition, and plays a role in relationships between organisms, including plant-fungus, insect-fungus and fungusfungus interactions. (Note that, throughout this chapter, "chitinolytic enzymes" refers to enzymes secreted extracellularly, unless otherwise indicated.)
Fungal strains assigned to the genera Trichoderma and Gliocladium are wellknown producers of chitinolytic enzymes and are used commercially as sources of these proteins. Additional interest in these enzymes is stimulated by the fact that chitinolytic strains of Trichoderma and Gliocladium are among the most effective agents for biological control of plant diseases and can be serious pathogens for mushroom farming (Chet, 1987; Harman, 1990; Harman et al., 1993a; Komatsu, 1976; Lo et al., 1996; Muthumeenakshi et al., 1994; Samuels, 1996; Speranzini et al., 1995; Tronsmo, 1991; this volume). Evidence is presented in this chapter that supports the correlation between extracellular production of chitinolytic enzymes and biocontrol or mycoparasitic ability of these fungi.
