Mutation-Screening in Xylanase-Producing Strains by Ion Implantation

摘要

With ion implantation (N~+, energy 10 keV and dosage 1.56 x 10~(15)N~+ cm~(-2)), a high xylanase-producing strain Aspergillus nlger N212 was selected. Based on an orthogonal experiment, an optimal fermentation condition was designed for this high-yield strain. The suitable medium was composed of 8% corncob; 1.0% wheat bran; 0.1% TWEEN20; 0.5% (NH_4)_2SO_4; 0.5%NaNO_3; 0.5%FeSO_4, 7.5 x 10~(-4); MnSO_4·H_2O, 2.5 x 10~(-4); ZnSO_4, 2.0 X 10~(-4); CoCl_2, 3.0 x 10~(-4) . At present, under our experiment condition, xylanase activity of Aspergillus niger N212 reached a level of 600 IU/ml, almost increased by 100% in xylanase production and the time of yielding xylanase was largely reduced to 12 h at 28℃.