Oleaginous yeasts as novel production platforms for acetyl-CoA derived chemicals

Several societally important chemicals that can be produced by microbes are formed via the central cellular metabolite acetyl-CoA (ACoA).

Development of platform strains with high levels of available ACoA is thus highly desired in order to improve process efficiency and economy.

Successful attempts at increasing the ACoA pool have been made in model organisms, but achieving large increases are challenging due to the tightly regulated metabolism surrounding this molecule.

This project will take a different approach by utilizing non-model microbes that naturally form high ACoA levels during specific cultivation conditions: the oleaginous yeasts.

These yeasts accumulate high amounts of lipids from ACoA during nitrogen starvation and have high potential to become useful platform strains for ACoA products if only the lipid formation trait could be blocked or removed.

Therefore, an inducible system for gene expression attenuation will be constructed that will allow for downregulation of the fatty acid (FA) biosynthesis pathway during nitrogen starvation.

The inducible nature of the system will allow the pathway to be expressed during the growth phase where FA formation is essential for cell viability and shut off during the lipid accumulation phase.

To evaluate the strains with the highest reduction in FA and lipid formation for their use as ACoA cell factories, heterologous expression of the pathway for formation of the bioplastics precursor polyhydroxybuturate (PHB) will be used.