Study On The Hydrolysis Of Chitosan By E7 Strain

About 30 chitosan-degrading fungus were isolated from soil. These micro-organism was used for producing chitosanase in a minimal medium containing chitosan as the sole carbon source.E7 strain which produce higher chitosanase activity was isolated from these micro-organism.The optimal conditions for E7 strain producing chitosanase were 250r/min, 28 癈 incubating temperature, medium pH 5. 0, 1% chitosan, tryptone as nitrogen sources. Metal ions like Mn2+ can induce producing chitosanase strongly, but Ca2+ inhibite the reactions.An extracellular chitosanase from the culture supernatant of E7 was purified to an apparent homogeneity by SDS-PAGE through centrifugation dialyzed concentrated by vacuum-equipped rotaevaporator and PAGE. The chitosanase had a molecular mass of 31KD. Through the analytical method of chitosan oligosaccharides by paper chromatograpHy found that by endo-splitting activity,the chitosanase hydrolysed chitosan to form chitosan oligomers .The ITS rRNA region of E7 were amplified ,cloned and sequenced.The sequence was compared with ITS rRNA region of other fungus registered in GenBank. The results showed that the ITS of E7 was homologic with penicillium. Then E7 was identified as penicillium sp according with the morpHological characteristics of E7 cells and clones.The N-terminal amino acid sequence of the enzyme was determined as APYQTRILET, which provides useful information for further gene cloning of this enzyme.