Membrane Engineering for Carotenoid Production in <i>Escherichia coli</i>

Abstract

Carotenoids are a class of highly hydrophobic compounds synthesized by plants in limited quantities. This study explores the potential for increasing the production yield of lycopene, a typical carotenoid compound, through engineered Escherichia coli. Given that lycopene biosynthesis occurs within microbial hosts and it is subsequently stored within lipid membranes, this study focuses on the impact of inducing membrane vesicles on lycopene yield by expressing monoglycosyldiacylglycerol synthase (MGS) or diglucosyldiacylglycerol synthase (DGS) from Acholeplasma laidlawii and inserting the upstream isopentenol utilization pathway (IUP) into the chromosome. The effect of MGS and DGS on lipid production in the cell was quantified. The results show that inserting the IUP into the chromosome increased the specific lycopene yield by 2.1-fold compared to the plasmid-based system when using a PproD constitutive promoter and by 2.0-fold when using the inducible Ptrc promoter. The expression of MGS and DGS resulted in a small increase of 31% and 33% (w/w) lipid content, respectively. When expressed in lycopene producing strains, the lycopene content decreased in the IUP strains but increased in the negative control strain expressing only the native MEP pathway from undetectable levels to 0.34 ± 0.08 mg/g.

Keywords

• isoprenoids
• hydrophobic products
• lycopene
• β-carotene
• isopentenol utilization pathway (IUP)