Breeding of high dye-decolorization strain by UV mutagenesis

Penicillium citrimim was mutagenized by UV-irradiation and a high dye-decolorization mutant Z3 was obtained. Its optimal growth conditions and dye decolorizing ability were studied. According to the orthogonal experiments, carbon source was the key to the growth of the strain Z3, with temperature, nitrogen source, pH value having much less effect than carbon source and had the similar effect. The best growth condition of strain Z3 was that temperature was 30°C, pH was 7, carbon source was sucrose, and nitrogen source was sodium nitrate. The malachite green decolorization rate of strain Z3 is higher than that of strain Z0, increased by 18% in comparison with Z0. Stain Z3 keeps stable after 8 generations of reproduction, which displays perfect genetic stability.