Light regulated overproduction of farnesyl pyrophosphate (FPP) in Saccharomyces cerevisiae
Farnesyl pyrophosphate (FPP) is an important metabolic intermediate that is required in the production of numerous industrially relevant compounds, such as the plant hormone Gibberellic acid. We seek to optimize FPP production levels in S. cerevisiae by overexpressing selected enzymes and regulators in the endogenous mevalonate biosynthesis pathway. To balance expression levels of the mevalonate genes, we created a library of transcription units to drive their expression. The transcription units are composed of an artificial transcription factor (aTF) expression cassette and a promoter with different multiples of the aTF binding site. This library of transcription units will be genetically fused with each mevalonate gene and then integrated in parallel into multiple loci in the yeast genome. We will identify variants with improved FPP production by co-expressing the β-carotene biosynthesis enzymes, phytoene synthase and phytoene desaturase. Increased FPP will enable improved β-carotene biosynthesis, which can be detected via fluorescence. To achieve light-regulated production of FPP, we are developing a transcription factor based on the photoreceptor photoactive yellow protein (PYP), which will be used to drive expression of the aTF units in response to blue light irradiation.