Strain improvement and optimization of the media composition of chitosanase-producing fungus Aspergillus sp. CJ 22-326

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.