A method of producing flavonoids through fermentation has significant commercial value in the pharmaceutical industry where it can be used to produce therapeutic agents with antiviral, antibacterial, anticancer, and other properties.
Existing methods of producing flavonoids through fermentation require supplementation of the culture media with phenylpropanoic precursors -- expensive compounds that add significantly to production cost. Additionally, these methods also require two different culture media formulations to support protein expression and flavonoid production respectively. This two-stage culture introduces process complexity that complicates efforts to scale up flavonoid production. This invention addresses this problem with novel strains of microbes that enable flavonoid production in a single medium formulation without precursor supplementation.
This invention describes a set of Escherichia coli strains capable of producing naringenin -- an important flavonoid precursor -- using glucose as a source of nutrition. These E. coli cells were modified to express four yeast- and plant-derived genes to produce the enzymes making up the naringenin synthesis pathway. The genetic construct containing these genes was designed with a combination of inducible and constitutive promoters to balance their respective expression levels and maximize naringenin yield. Using these E. coli strains, the inventors have successfully achieved a final naringenin titer of 29 mg/L directly from glucose with no precursor supplementation.
Single minimal media formulation used throughout fermentation process
- Eliminates need for precursor supplementation, thereby reducing substrate-related costs by several hundred fold