Engineering Yarrowia lipolytica as a platform for synthesis of drop-in transportation fuels and oleochemicals

Significance

Cost-efficient production of fuels and oleochemicals requires the host strain to be highly lipogenic and suitable for large-scale production. We demonstrate that Yarrowia lipolytica represents a promising biorefinery platform for sustainable production of drop-in transportation fuels and oleochemicals. Understanding the mechanistic details of the lipogenic phenotype, particularly the cellular compartmentalization of distinct metabolic pathways, fatty acid synthase structure, activating free fatty acids to acyl-CoAs, and decoupling nitrogen starvation from lipogenesis, allowed us to efficiently produce fatty acid ethyl esters, fatty alkanes, medium chain-length fatty acids, fatty alcohols, and triacylglycerides (TAGs). We envision that this report constitutes foundational work in developing an oleaginous yeast platform to upgrade low-value carbons to high-value fuels and oleochemicals in the foreseeable future.

Abstract

Harnessing lipogenic pathways and rewiring acyl-CoA and acyl-ACP (acyl carrier protein) metabolism in Yarrowia lipolytica hold great potential for cost-efficient production of diesel, gasoline-like fuels, and oleochemicals. Here we assessed various pathway engineering strategies in Y. lipolytica toward developing a yeast biorefinery platform for sustainable production of fuel-like molecules and oleochemicals. Specifically, acyl-CoA/acyl-ACP processing enzymes were targeted to the cytoplasm, peroxisome, or endoplasmic reticulum to generate fatty acid ethyl esters and fatty alkanes with tailored chain length. Activation of endogenous free fatty acids and the subsequent reduction of fatty acyl-CoAs enabled the efficient synthesis of fatty alcohols. Engineering a hybrid fatty acid synthase shifted the free fatty acids to a medium chain-length scale. Manipulation of alternative cytosolic acetyl-CoA pathways partially decoupled lipogenesis from nitrogen starvation and unleashed the lipogenic potential of Y. lipolytica. Taken together, the strategies reported here represent promising steps to develop a yeast biorefinery platform that potentially upgrades low-value carbons to high-value fuels and oleochemicals in a sustainable and environmentally friendly manner.