Lytic enzyme complex of an antagonistic Bacillus sp. X-b: isolation and purification of components.

Bacillus sp. X-b, a biocontrol agent against certain plant pathogenic fungi, secretes a complex of hydrolytic enzymes, composed of chitinase, chitosanase, laminarinase, lipase and protease. Homogenized mycelium of basidiomycete Macrolepiota procera induced activities of these enzymes more effectively than colloidal chitin or partially purified cell walls of another basidiomycete Polyporus squamosus. Subjected to a multi-step purification, the specific activity of chitinase increased 36-fold, chitosanase 69-fold, lipase 44-fold and laminarinase 15-fold. Partially purified chitinase showed two major bands with molecular masses of 46,000 and 35,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis while chitosanase and lipase appeared as single bands with molecular masses of 27,000 and 62,000, respectively.