响应面法优化根霉菌产麦角固醇的液体发酵工艺

以米根霉(Rhizopus oryzae ZW017)发酵产麦角固醇的产量为响应值,对其液体发酵工艺进行优化。采用HPLC法检测菌株产麦角固醇含量,在单因素筛选试验基础上,以PDB液体发酵培养为基础条件,应用响应面分析法(RSM)对碳源、氮源及发酵时间进行优化。结果表明:以葡萄糖、酵母膏分别为最佳碳、氮源;最佳工艺条件为:PDB基础培养基中添加葡萄糖3g/L、酵母膏5g/L、发酵培养9.64d,麦角固醇平均产量达5761.83μg/100mL,较优化前提高了247.86%,与构建模型理论预测值(5818.39μg/100mL)相吻合,且100mL液体培养基中麦角固醇产量占菌体细胞干质量(0.36g)的1.60%。

Application of Response Surface Methodology for Optimization of Liquid-State Fermentation Process for Ergosterol Production by Rhizopus oryzae

In order to maximize intracellular ergosterol production in Rhizopus oryzae in liquid-state fermentation,nitrogen and carbon sources and fermentation time were optimized using response surface methodology.Ergosterol was determined by HPLC and the fermentation medium used was based on PDB liquid medium.The effects of carbon and nitrogen source types on ergosterol production were examined.One-factor-at-a-time experiments were conducted to analyze the effects of yeast extract,glucose and fermentation on ergosterol production.The optimum carbon and nitrogen sources were found to be glucose and yeast extract,respectively.The optimum fermentation process was achieved after 9.64 d of culture in a modified PDB liquid medium containing 3 g/L glucose and 5 g/L yeast extract.Under these conditions,the average ergosterol production was 5761.83μg /100 mL of fermentation broth,which was in agreement with the predicted value(5.818.39μg /100 mL of fermentation broth) from the model established and 247.86% higher than before the optimization.Moreover,the ratio of ergosterol to dry cell was 1.60%(100 mL liquid culture medium).