Amplification of FPP Synthase
Isoprenoid Accumulation During Fed Batch Fermentation
Over-expression of GGPP synthase in erg9 mutant strains was accomplished with the native yeast enzyme (coded by the BTS1 gene), a bacterial enzyme (coded by the crtE gene from Erwinia uredovora), and two filamentous fungal enzymes (coded by the al-3 gene from Neurospora crassa and the ggs gene from Gibberella fujikuroi). The genes were inserted into a high copy-number plasmid, and expressed in yeast using strong yeast promoters obtained from the PGK or ADH1 genes. Over-expression of the GGPP synthases led to higher accumulations of GGOH. The highest levels of GGOH were obtained with over-expression of the crtE gene.
Over-expression of the native FPP synthase (coded by the ERG20 gene) was accomplished by inserting the gene into a high-copy-number plasmid, and expressed using the strong yeast promoter obtained from the GPD (also known as GAPDH or TDH3) gene. Elevated levels of FPP synthase led to increased accumulation of GGOH, but no increase in farnesol accumulation.