Plurification and properties of chitosanase from chitinolytic β-Proteobacterium KNU3

초록

A bacterial strain concurrently producing extracellular chitosanase and chitinase was isolated from soil and identified as a member of the beta-subgroup of Proteobacteria through its 16S rRNA analysis and some biochemical analyses. The newly discovered strain, named as KNU3, had 99% homology of its 16S rRNA sequence with chitinolytic beta-Proteobacteriun? CTE108. Strain KNU3 produced 34 kDa of chitosanase in addition to two chitinases of 68 kDa and 30 kDa, respectively. The purified chitosanase protein (ChoK) showed activity toward soluble, colloidal, and glycol chitosan, but did not exhibit any activity toward colloidal chitin. The optimum pH and temperature of ChoK were 6.0 and 70degreesC, respectively. The chitosanase was stable in the pH 4.0 to 8.0 range at 70degreesC, while enzyme activity was relatively stable at below 45degreesC. MALDI-TOF MS and N-terminal amino acid sequence analyses indicated that ChoK protein is related to chitosanases from Matsuebacter sp. and Sphingobacterium multivorum. HPLC analysis of chitosan lysates revealed that glucosamine tetramers and hexamers were the major products of hydrolysis.

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