Production, purification and characterization of chitosanase produced by Gongronella sp. JG

To optimize the production condition of chitosanases of Gongronella sp. JG and to characterize the major chitosanase.

In the optimized medium and culturing condition, strain JG produced 800 micromol min(-1) l(-1) chitosanase activity at 72 h. The major chitosanase - csn1 was purified through three chromatography steps: CM (carboxymethyl)-Sepharose fast flow (FF), Sephacryl S200, SP (sulfopropyl)-Sepharose FF. The molecular weight and the pI value of csn1 were about 90,000 Da and 5 x 8, respectively. Its specific activity was 82 micromol min(-1) mg(-1). The optimal reaction pH for csn1 was between 4 x 6 and 4 x 8. The optimal reaction temperature was 50 degrees C. The half-life of csn1 at 50 degrees C was estimated to be about 65 min. Mn(2+) was a strong stimulator of csn1 activity, both at 1 and 10 mmol l(-1). csn1 showed its highest activity with chitosan of 85% degree of deacetylation, but did not hydrolyse colloidal chitin and carboxylmethyl cellulose. In 20 mmol l(-1) sodium acetate buffer (pH 4 x 8) and at 50 degrees C, the K(m) of csn1 was calculated to be 4 x 5 mg ml(-1).

The production condition of chitosanases by Gongronella JG was optimized and the major chitosanase, csn1, was characterized.

The present work for the first time reported the production, purification and characterization of chitosanases produced by fungus of Gongronella sp. These results provided us more information on fungal chitosanases.