Increasing lipid yield in Yarrowia lipolytica through phosphoketolase and phosphotransacetylase expression in a phosphofructokinase deletion strain.

Background: Lipids are important precursors in the biofuel and oleochemical industries. Yarrowia lipolytica is among the most extensively studied oleaginous microorganisms and has been a focus of metabolic engineering to improve lipid production. Yield improvement, through rewiring of the central carbon metabolism of Y.

Production of 10-methyl branched fatty acids in yeast.

Background: Despite the environmental value of biobased lubricants, they account for less than 2% of global lubricant use due to poor thermo-oxidative stability arising from the presence of unsaturated double bonds. Methyl branched fatty acids (BFAs), particularly those with branching near the acyl-chain mid-point, are a high-performance alternative to existing vegetable oils because of their low melting temperature and full saturation.

Results: We cloned and characterized two pathways to produce 10-methyl BFAs isolated from actinomycetes and γ-proteobacteria.

Promoters for lipogenesis-specific downregulation in Yarrowia lipolytica.

Yarrowia lipolytica is a non-conventional yeast with potential applications in the biofuel and biochemical industries. It is an oleaginous yeast that accumulates lipids when it encounters nutrient limitation in the presence of excess carbon. Its molecular toolbox includes promoters for robust constitutive expression, regulated expression through the addition of media components and inducible expression during lipid accumulation.

Engineering triacylglycerol production from sugars in oleaginous yeasts.

Oleaginous yeasts natively produce surplus triacylglycerol lipid and can be engineered for higher yield and productivity. Most enzymatic steps of triacylglycerol production are characterized, but key parts of the pathway remain unknown. This introduces uncertainty to metabolic engineering strategy and the upper limit of achievable lipid yield.

High-oleate yeast oil without polyunsaturated fatty acids.

Background: Oleate-enriched triacylglycerides are well-suited for lubricant applications that require high oxidative stability. Fatty acid carbon chain length and degree of desaturation are key determinants of triacylglyceride properties and the ability to manipulate fatty acid composition in living organisms is critical to developing a source of bio-based oil tailored to meet specific application requirements.

Results: We sought to engineer the oleaginous yeast for production of high-oleate triacylglyceride oil.

Engineering of a high lipid producing Yarrowia lipolytica strain.

Background: Microbial lipids are produced by many oleaginous organisms including the well-characterized yeast Yarrowia lipolytica, which can be engineered for increased lipid yield by up-regulation of the lipid biosynthetic pathway and down-regulation or deletion of competing pathways.

Results: We describe a strain engineering strategy centered on diacylglycerol acyltransferase (DGA) gene overexpression that applied combinatorial screening of overexpression and deletion genetic targets to construct a high lipid producing yeast biocatalyst. The resulting strain, NS432, combines overexpression of a heterologous DGA1 enzyme from Rhodosporidium toruloides, a heterlogous DGA2 enzyme from Claviceps purpurea, and deletion of the native TGL3 lipase regulator.