利用溶氧作为控制信号补料分批培养生产PHA的研究

利用已构建的工程菌Escherchia coli XL1-Blue(pKSABC),在20L自动发酵罐里进行补料分批培养。研究表明,底物浓度、温度、pH、DO等参数是影响菌体生长和PHA积累的重要因素;通过补料分批培养可以提高PHA的积累量。通过对DO在发酵过程中的变化规律的分析,确定DO作为补料时间的在线控制信号。补料的原则是,使发酵前期菌体大量生长,发酵后期PHA大量积累。在优化条件下,对工程菌Escherchia coliXL1-Blue(pKSABC)进行了60 h的补料分批培养,菌体浓度、PHA浓度和PHA占细胞干重的百分比分别为179g/L,132g/L,73.7%。

Studies on the production of PHA by fed-batch culture with DO-control method employing Escherchia coli XL1-Blue(pKSABC)

By using the 20L reactor ,during the process of fet-batch cuiture of Escherchia coli XL1-Blue(pKSABC),it was found that the level of dissolved oxygen (DO),the concentration ratio (C/N) and the range of carbon and nitrogen source were all important parameters affecting cell growth and PHA accumulation. DO and pH could be used to decide the time for the nutrition feeding. Finally, the optimal feeding strategy, by which the cell growth was emphasized in early process and the PHA accumulation was promoted in late process,was carried out. After 60 h fed-batch culture under the optimal conditions,cell concentration, PHA concentration and PHA content were reached up to 179g/ L,132g/ L and 73.7% respectively.