1. Enhancement of l-phenylalanine production in Escherichia coli by heterologous expression of Vitreoscilla hemoglobin
- Author
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Weibin Wu, Qing-Gen Huang, Guo Xiaolei, Feng Qi, Zhang Mingliang, and Jianzhong Huang
- Subjects
0106 biological sciences ,0301 basic medicine ,Phenylalanine ,Biomedical Engineering ,Bioengineering ,Prephenate dehydratase ,Biology ,medicine.disease_cause ,01 natural sciences ,Applied Microbiology and Biotechnology ,03 medical and health sciences ,Bacterial Proteins ,010608 biotechnology ,Drug Discovery ,medicine ,Escherichia coli ,Promoter Regions, Genetic ,chemistry.chemical_classification ,Strain (chemistry) ,Process Chemistry and Technology ,Truncated Hemoglobins ,General Medicine ,Amino acid ,030104 developmental biology ,Biochemistry ,chemistry ,Fermentation ,Chorismate mutase ,Molecular Medicine ,Heterologous expression ,Biotechnology - Abstract
l-Phenylalanine is an important amino acid that is widely used in the production of food flavors and pharmaceuticals. Generally, l-phenylalanine production by engineered Escherichia coli requires a high rate of oxygen supply. However, the coexpression of Vitreoscilla hemoglobin gene (vgb), driven bya tac promoter, with the genes encoding 3-deoxy-d-arabinoheptulosonate-7-phosphate synthetase (aroF) and feedback-resistant chorismate mutase/prephenate dehydratase (pheAfbr ), led to increased productivity and decreased demand for aeration by E. coli CICC10245. Shake-flask studies showed that vgb-expressing strains displayed higher rates of oxygen uptake, and l-phenylalanine production under standard aeration conditions was increased. In the aerobic fermentation process, cell growth, l-phenylalanine production, and glucose consumption by the recombinant E. coli strain PAPV, which harbored aroF, pheAfbr , and tac-vgb genes, were increased compared to that in the strain harboring only aroF and pheAfbr (E. coli strain PAP), especially under oxygen-limited conditions. The vgb-expressing strain PAPV produced 21.9% more biomass and 16.6% more l-phenylalanine, while consuming only approximately 5% more glucose after 48 H of fermentation. This study demonstrates a method to enhance the l-phenylalanine production by E. coli using less intensive and thus more economical aeration conditions.
- Published
- 2017