耐辐射短梗霉黑色素的发酵条件优化及稳定性研究

Study on the Optimization of Fermentation Conditions and Stability of Melanin from a Radiation-resistant Aureobasidium pullulans

【目的】利用响应面法对出芽短梗霉菌株MF1发酵水溶性黑色素工艺条件进行优化,开展稳定性研究。【方法】利用Design-expert 7.5设计软件,以黑色素产量为指标,采用Plackett-Burman法筛选出三个重要因素,使用Box-Benhnken中心组合设计并进行条件优化。【结果】响应面优化及各因素交互作用分析确定最佳发酵条件为:装添量为100 m L,葡萄糖为10.3 g/L,酵母浸粉为2.02 g/L时,黑色素最高产量达到0.53g/L。所得黑色素具有良好的水溶性,较高的酸碱、热稳定性,不易被氧化还原,金属离子对色素稳定性影响不显著。【结论】葡萄糖、酵母浸粉和装填量为影响黑色素产量的三个主要因素,为天然水溶性黑色素的中试放大、大规模生产及应用奠定了基础。

[ Objective] Response surface analysis was applied in current study to optimize the fermentation process of water - soluble melanin produced by Aureobasidium pulluans strain MF1, and to assess the stability of the melanin. [ Method ] Three factors were determined to be most influential factors on melanin yield among all tested factors via Plackett -Burman design. Box- Behnken design was subsequentially applied to adjust the parameters during the fermentation. All analysis was processed in Design - expert 7.5 software. [ Result]The fermentation achieved the highest melanin yield of 0.53 g/L in raw broth with 100 mL broth in 500 mL flask, of which the glucose concentration was 10.3 g/L, and yeast extract was 2.02 g/L. The mela- nin yielded from our process was fair in water solubility, and was of high stability in heat, acid, alkaline, oxi- dation or reduction circumstance. Metal ions showed insignificant effect on pigment stability. [ Conclusion ] The results showed that the glucose, yeast extract and the filling amount were fundamental factors influencing the melanin fermentation produced with A. puUuans strain MF1. Our study laid foundation for the pilot scale, large- scale production of water- soluble natural melanin in the future.