Purification and characterization of an antifungal chitinase from Bacillus sp. SL-13

Bacillus sp.SL-13 produced antifungal proteins.The growth of the plant-pathogenic fungi Rhizoctonia solani was considerably inhibited by the presence of the SL-13 culture supernatant.The proteins were purified by DEAE-Sepharose fast flow ion exchange column chromatography and Sephadex G-75 gel filtration,and the main antifungal protein was purified to be chitinase.The molecular weight of chitinase was estimated to be 36 kD by 12%SDS PAGE.The optimal pH and temperature for the chitinase was 7.0 and 50℃.It demonstrated that the enzyme was stable from pH 5 to 9 and form 40?C to 60℃.The enzyme still kept 70%activity when incubated at 121℃,0.11MPa up to 20 minutes and the enzyme is also not lost the activity when treated with protease K and ultraviolet radiation for 1.5hours.It is very suitable for the use in a relatively unstable environment,exhibiting effective biological control.