Dynamic control of ERG20 expression combined with minimized endogenous downstream metabolism contributes to the improvement of geraniol production in Saccharomyces cerevisiae

Scientific Achievement

In this study, we further improved the geraniol production through reducing the endogenous metabolism of geraniol and controlling the precursor geranyl diphosphate flux distribution. The deletion of OYE2(encoding an NADPH oxidoreductase) or ATF1(encoding an alcohol acetyltransferase) both involving endogenous conversion of geraniol to other terpenoids, improved geraniol production by 1.7-fold or 1.6-fold in batch fermentation, respectively. In addition, we found that direct down-regulation of ERG20expression, the branch point regulating geranyl diphosphate flux, does not improve geraniol production. Therefore, we explored dynamic control of ERG20expression to redistribute the precursor geranyl diphosphate flux and achieved a 3.4-fold increase in geraniol production after optimizing carbon source feeding. Furthermore, the combination of dynamic control of ERG20 expression and OYE2deletion in LEU2prototrophic strain increased geraniol production up to 1.69 g/L with pure ethanol feeding in fedbatch fermentation, which is the highest reported production in engineered yeast.

Significant and Impact

An efficient geraniol production platform was established by reducing the endogenous metabolism of geraniol and by controlling the flux distribution of the precursor geranyl diphosphate. The present work also provides a production basis to synthesis geraniol-derived chemicals, such as monoterpene indole alkaloids.

Research Details

·Previously, we achieved a significant increase in geraniol production through expressing geraniol synthase from Valeriana officinalisand regulating GPP synthesis.

·We further engineered strains through dynamic control of ERG20to fine-tune the GPP flux combined with minimized geraniol endogenous conversion.

·Combining these strategies together with LEU2 auxotrophic complementation, the final geraniol production reached 1.69 g/L in fed-batch fermentation.