Discovery and Characterization of a Novel Chitosanase from Paenibacillus dendritiformis by Phylogeny-Based Enzymatic Product Specificity Prediction

In the process of genome mining for novel chitosanases by phylogeny-based enzymatic product specificity prediction, a gene named Csn-PD from Paenibacillus dendritiformis was discovered. The enzyme was classified as a member of the GH46 family of glycoside hydrolase based on sequence alignment, and it was functionally expressed in Escherichia coli BL21 (DE3). The recombinant chitosanase was purified, and its molecular weight was estimated to be 31 kDa by SDS-PAGE. Csn-PD displayed maximal activity toward colloidal chitosan at pH 7.0 and 45 degrees C, respectively. A combination of thin-layer chromatography and electrospray ionization-mass spectrometry results showed that Csn-PD exhibited an endotype cleavage pattern and hydrolyzed chitosan to yield (GlcN)(2) as the major product. The unique enzymatic properties of this chitosanase may make it a good candidate for (GlcN)(2) production.