Efficient Production of Pseudoionone with Multi-pathway Engineering in Escherichia coli.

Aims: This study aimed to achieve efficient production of pseudoionone in Escherichia coli. Methods and Results: Firstly, a stable lycopene-producing strain was constructed by integrating lycopene biosynthetic pathway into the chromosome. Further introduction of the Cucumis melo carotenoid cleavage dioxygenase 1 (cmCCD1) gene resulted in the production of pseudoionone. Then, the tricarboxylic acid cycle (i.e. sdhABCD and sucAB), pentose phosphate pathway (i.e. talB), and methylerythritol 4-phosphate pathway (i.e. idi and dxs) genes were modulated to improve the production of lycopene and accordingly pseudoionone. Regulation of the expression of talB and sdhABCD for improving NADPH supplies led to a 2.81-fold increase of pseudoionone production. Further engineering of dxs and idi increased the production of pseudoionone by 8.34-fold. Followed by bioprocess optimization, 24 mg l(-1) pseudoionone with a specific production of 8.55 mg g(-1) in shake flask was achieved. Conclusions: The combination of metabolic engineering and bioprocess engineering increased the production of pseudoionone by more than 185-fold. Significance and Impact of the Study: The present study promises a green and sustainable route for pseudoionone production using a microbial cell factory.