INDUCTION AND PURIFICATION OF BEAUVERIA-BASSIANA CHITINOLYTIC ENZYMES

Chitinolytic enzyme production and induction in an entomopathogenic fungus Beauveria bassiana (an isolate from a praying mantis) was investigated in liquid culture medium. Extracellular chitinolytic proteins could be induced in ca. 20 hr after washed mycelia were transferred to a medium containing colloidal chitin as a sole carbon and nitrogen source. Chitinolytic enzymes were partially purified by ammonium sulfate precipitation followed by gel filtration with a Cellulofine GCL 2000-sf column. Two main degradation activity peaks toward glycolchitin were eluted out. Peak 1 degraded glycolchitin and p-nitrophenyl-β-D-N-acetylglucosaminide (pNP-NAG1), indicating mixed activities of endo- and exochitinase. Peak 2 degraded glycolchitin but not pNP-NAG1, suggesting endochitinase activity. Peak 2 was further purified to homogeneity by ion-exchange chromatography on a Mono Q column and gel filtration through a joint-column of TSKgel G3000SW and G2000SW. The molecular weight of the endochitinase thus purified was estimated to be 45 kDa by SDS-polyacrylamide gel electrophoresis. Copyright © 1993 Academic Press. All rights reserved.