Fu Weiqi, Lin Jianping, Cen Peilin
Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China.
Bioresour Technol. 2008 Jul;99(11):4864-70. doi: 10.1016/j.biortech.2007.09.039. Epub 2007 Nov 13.
5-Aminolevulinate (ALA) production with recombinant Escherichia coli Rosetta (DE3)/pET28a(+)-hemA was studied. In batch fermentation, the addition of glucose and glycine was effective to improve ALA production. Then the fed-batch fermentation was conducted with continuous feeding of precursors. When the concentrations of succinic acid and glycine were 7.0 g/l and 4.0 g/l, respectively, in the feeding, the ALA yield reached 4.1g/l. But the molar yield (ALA/glycine) was decreased in the fed-batch fermentation compared to batch fermentation. And it was found that the pH control during fed-batch cultivation was very important for the cell growth and ALA production. A two-stage pH value controlling strategy was suggested, in which, the pH value in the first 6h was regulated at pH 5.9, after then at pH 6.2, and the ALA yield was as high as 6.6g/l via fed-batch fermentation.
研究了用重组大肠杆菌Rosetta (DE3)/pET28a(+)-hemA生产5-氨基乙酰丙酸（ALA）的情况。在分批发酵中，添加葡萄糖和甘氨酸可有效提高ALA产量。然后进行补料分批发酵，持续补加前体物质。当补料中琥珀酸和甘氨酸的浓度分别为7.0 g/l和4.0 g/l时，ALA产量达到4.1 g/l。但与分批发酵相比，补料分批发酵中（ALA/甘氨酸的）摩尔产量有所下降。并且发现补料分批培养过程中的pH控制对细胞生长和ALA生产非常重要。提出了一种两阶段pH值控制策略，即在最初6小时将pH值调节至5.9，之后调节至6.2，通过补料分批发酵，ALA产量高达6.6 g/l。
