Purification and characterization of an extracellular chitinase from the antifungal biocontrol agent Streptomyces halstedii.

An extracellular chitinase from Streptomyces halstedii AJ-7, a broad spectrum antifungal biocontrol agent, was characterized and purified. The apparent molecular weight of the purified protein was 55 kDa, Km value and Vmax of the protein for colloidal chitin were 3.2 mg ml(-1) and 118 micromol h(-1), respectively. The growth and chitinase activity of S. halstedii AJ-7 were enhanced by adding of 0.1% killed mycelium of Fusarium oxysporium in a medium containing 0.2% colloidal chitin.