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• 生物工程 •    下一篇

布拉酵母增殖培养基及高密度培养工艺优化

刘开放,席志文,黄林娜,惠丰立   

  1. 南阳师范学院
  • 收稿日期:2018-04-25 修回日期:2019-03-12 出版日期:2019-04-25 发布日期:2019-05-05
  • 通讯作者: 惠丰立 E-mail:huifl@126.com
  • 基金资助:
    云南西双版纳热带雨林腐木中木糖发酵酵母菌

Optimization of Enrichment Eermentation Medium and High Cell Density Fermentation for Saccharomyces boulardii

Kai-Fang LIUZhi-wen XI2,Lin-na HUANG2,   

  • Received:2018-04-25 Revised:2019-03-12 Online:2019-04-25 Published:2019-05-05

摘要: 为实现布拉酵母高密度培养,对其高密度发酵培养基和发酵工艺进行优化。采用 Plackett-Burman(P-B)实验筛选培养基中的显著因素,并进行中心组合实验(central composite design,CCD)。通过人工神经网络(artificial neural network,ANN)和响应面(response surface methodology,RSM)建立菌体干重与培养基之间的关系模型,利用遗传算法(genetic algorithm,GA)进行全局寻优。结果表明,ANN模型有着较好的数据拟合能力和预测能力,更适合处理复杂的非线性问题。GA优化获得最佳培养基:葡萄糖 40.52 g/L、蛋白胨36.8g/L、玉米浆17.32g/L、硝酸钾14 g/L、酵母营养盐1.5 g/L、磷酸二氢钾0.6 g/L、硫酸镁0.8 g/L。利用该培养基进行摇瓶培养,菌体干重可达到8.21g/L,比优化前提高了1.39倍。在此基础上利用1L发酵罐培养确定最佳发酵工艺:温度30℃、接种量10%、pH5.0、溶氧40%。利用50L发酵罐进行扩大培养,流加葡萄糖和蛋白胨控制发酵液中葡萄糖3g/L、氨氮0.06g/L,菌体干重达到51.21g/L。

关键词: 布拉酵母, 神经网络, 遗传算法, 增殖培养基, 高密度培养

Abstract: To achieve high cell density, we attempted to optimize the high-cell-density fermentation medium and the fermentation process of S. boulardii. Plackett-Burman design and central composite design (CCD) were applied to screen for the significant influencing components in fermentation medium. Response surface methodology (RSM) and artificial neural network (ANN) were then employed to model the relationship between the dry S. boulardii yield and the composition of the medium, which enables the subsequent global optimization of medium composition using genetic algorithm. The results showed that the ANN model, which is more suitable for complex and nonlinear modeling task, achieved higher fitting ability and prediction accuracy when compared to those of the RSM model. With genetic algorithm, the optimal composition of our medium was obtained as follows: glucose 40.52 g/L, peptone 36.8 g/L, corn steep liquor 17.32 g/L, KNO3 14 g/L, yeast nutrients 1.5 g/L, KH2PO4 0.6 g/L and MgSO4 0.8 g/L. Under the optimal condition, we showed that the dry cell mass of S. boulardii could reach 8.21 g/L by shake-flask fermentation, which was 1.39 folds higher than that achieved by the original condition. Based on these results, we determined the optimal high-cell-density culture condition of S. boulardii, i.e., temperature 30℃, 10% inoculum, pH 5.0 and 40% DO in a one-liter fermentation tank. Furthermore, we expanded the culture in a 50-liter fermentation tank. Glucose and peptone were added to maintain the glucose concentration at 3 g/L and the ammonia nitrogen concentration at 0.06 g/L. The dry cell mass of S. boulardii reached 51.21 g/L in the large scale experiment.

Key words: Saccharomyces boulardii, neural network, genetic algorithm, enrichment medium, high cell density fermentation

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