| 초록 |
Microbial fermentation of 5-aminolevulinic acid (ALA) has received much attention because of its potential in clinical applications. Overexpression of the related enzymes and an analogue transporter yielded remarkable achievements in ALA production, accompanying with deciphering its regulation. In spite of this, there is still significant room for carbon flux optimization to improve ALA production. This study aimed for precise carbon flux optimization for high ALA production in Escherichia coli expressing the ALA biosynthetic pathway. Initially. genes hemA and hemL were overexpressed with strong promoters and synthetic 5'-untranslated regions (5'-UTR). Then, the tricarboxylic acid (TCA) cycle was knocked-out for re-distribution of carbon flux toward the ALA production, additional precise tuning of carbon flux to the glyoxylate shunt by varying the transcriptional strength of aceA led to substantially improved cell growth and ALA production. Thus, this precise tuning of the glyoxylate cycle in a quantitative manner should also enable efficient production of other valuable products derived from the TCA cycle. |
