Fig. 1

Engineered S. cerevisiae cell factory to produce the early Taxol® precursors (taxadiene(s) and oxygenated taxanes), represents the BN6 strain in this study. The overexpressed genes in the mevalonate pathway are highlighted in red and heterologous genes are in olive. In this study, the oxygenated taxanes production starts with galactose induction, following by cyclisation of geranylgeranyl diphosphate (GGPP) to taxadiene and other diterpenes by the diterpene synthase, taxadiene synthase (TASY). CYP725A4 and a cytochrome P450 reductase catalyse the first hydroxylation of the Taxol® pathway, where taxadiene and its isomers are converted to taxadiene-5α-ol (T5α-ol) and other oxygenated taxanes. The heterologous genes include Hydroxymethylglutaryl-CoA synthase (mvaS) and acetyl-CoA acetyltransferase/HMG-CoA reductase (mvaE) from Enterococcus faecalis, and geranylgeranyl diphosphate synthase (crtE) from Xanthophyllomyces dendrorhous. Three copies of TASY with fusion solubility tags are chromosomally integrated in the yeast strains of this study to increase the CYP725A4 substrates (taxadiene and iso-taxadiene) titres [12]. Mevalonate-PP: (R)-5-diphosphomevalonate; HMG-CoA: hydroxymethylglutaryl-CoA; IPP: isopentenyl pyrophosphate; DMAPP: dimethylallyl diphosphate; GPP: geranyl diphosphate; FPP: farnesyl diphosphate; GGPP: geranylgeranyl diphosphate; GGOH: geranylgeraniol. Figure was created with BioRender.com