Stable and Efficient Biosynthesis of 5-Aminolevulinic Acid Using Plasmid-Free Escherichia coli
Stable and Efficient Biosynthesis of 5-Aminolevulinic Acid Using Plasmid-Free Escherichia coli
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使用无质粒大肠杆菌稳定高效地生物合成 5-氨基乙酰丙酸
DOI：
10.1021/acs.jafc.8b06496
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发表时间：
2019-02-06
影响因子：
6.1
通讯作者：
Qi, Qingsheng
中科院分区：
文献类型：
--
作者：
Cui, Zhiyong;Jiang, Zhennan;Qi, Qingsheng
5-氨基乙酰丙酸（5-ALA）是血红素生物合成途径的关键代谢中间体，在农业和医药领域具有广阔的应用前景。然而，基于质粒的表达系统的分离不稳定性和低产量阻碍了5-ALA的大规模生产。在本研究中，5-ALA CS生物合成途径的两个重要基因hemA和hemL被整合到大肠杆菌MG1655中，用于化学诱导染色体进化（CIChE）。 CIChE 菌株 MG136 中获得了最高的 hemA 和 hemL 拷贝数，每个基因组 98 个。该菌株在优化条件下5-ALA滴度达到2724mg/L。然后，经过适应性进化和recA的删除，菌株MG136a Delta recA::FRT可以稳定地从葡萄糖中产生4550 mg/L 5-ALA，是hemA-hemL单拷贝菌株MG1655-hemAL产生量的450倍。本研究构建了用于5-ALA生产的无质粒大肠杆菌菌株，为进一步调控代谢调控和优化发酵提供基础。
5-Aminolevulinic acid (5-ALA) is a key metabolic intermediate of the heme biosynthesis pathway, which has broad application prospects in agriculture and medicine. However, segregational instability of plasmid-based expression systems and low yield have hampered large-scale manufacture of 5-ALA. In this study, two important genes of the 5-ALA CS biosynthesis pathway, hemA and hemL, were integrated into Escherichia coli MG1655 for chemically induced chromosomal evolution (CIChE). The highest hemA and hemL copy-number, 98 per genome, was obtained in CIChE strain MG136. The 5-ALA titer of this strain reached 2724 mg/L in optimized condition. Then, after undergoing adaptative evolution and the deletion of recA, strain MG136a Delta recA::FRT could stably produce 4550 mg/L 5-ALA from glucose, 450 times the amount produced by hemA-hemL single copy strain MG1655-hemAL. This study constructed a plasmid-free E. coli strain for 5-ALA production, which will provide the basis for further manipulation of metabolic regulation and optimization of fermentation.