Abstract

A mutant Aspergillus sp. CJ 22-326-14 with higher production of chitosanase was selected by serial mutation procedure, and the optimization of medium components was performed using one-factor-at-a-time combined with orthogonal array design method. The results showed that chitosan, wheat bran and (NH₄)₂SO₄ were the most important components by one-factor-at-a-time experiments. And the optimal concentrations were obtained by orthogonal array design method as (g/L): chitosan 20, wheat bran 10, (NH₄) ₂SO₄ 2, KH₂PO₄  2 and MgSO₄·7H₂O  0.5. After the strain improvement and optimization of the media, the chitosanase activity from Aspergillus sp. CJ 22-326-14 reached to 3.92 U/mL in 250 mL flasks, which was nearly 4-fold increase of chitosanase production at the parent lowest level.

Key words: Aspergillus sp., chitosanase, mutant, fermentation, optimization, orthogonal array design method.