Purification and characterization of the chitosanase from <i>Aeromonas sp.</i> HG08

Abstract

In this work, the characterization of a chitosanase-producing bacterium isolated from soil was reported and this strain was grouped under the genus Aeromonas by virtue of its morphological, physiological properties and 16S rDNA gene sequences. It is the first report that the genus Aeromonas could produce chitosanase. Aeromonas sp. HG08 could secrete the chitosanase (named AsChi) with molecular weight of 70 kDa. The optimum pH and temperature of AsChi was 6.0 and 55°C, respectively. The activity of AsChi was markedly enhanced by Mn2+ and inhibited by Fe3+, Cu2+, Ag+ and Hg2+; additionally, the activity of AsChi was increased with the degree of deacetylation (DDA) of chitosan. Through viscosimetric assay,
AsChi probably hydrolyzed chitosan in an endo-type fashion.