APPLICATIONS OF TECHNOLOGY:
- Industrial lubricants and surfactants
- Personal care products
- Biofuel production
- Sustainable sourcing for fatty alcohols
- Highest titers and yields for fatty alcohols produced from cerevisiae yeast to date
- Allows for specific chemical modifications of fatty alcohols
Joint BioEnergy Institute (JBEI) researchers led by Jay Keasling have invented a technology to produce fatty alcohols from engineered yeast cells. By genetically modifying the yeast cells, researchers were able to produce high levels of long-chain alcohols in the 12-18 carbon range containing terminal alcohol groups. This approach is the first report of a bioproduct generated by yeast from feedstocks generated entirely from biomass, and represents the highest titers and yields reported to date in S. cerevisiae.
Fatty alcohols in the C12-C18 range are used in personal care products, lubricants, and potentially biofuels. These compounds can be produced from the fatty acid pathway by a fatty acid reductase (FAR), yet yields from the preferred industrial host Saccharomyces cerevisiae remain under 2% of the theoretical maximum from glucose. Dr. Keasling’s group improved titer and yield of fatty alcohols using an approach involving quantitative analysis of protein levels and metabolic flux, engineering enzyme level and localization, pull-push-block engineering of carbon flux, and cofactor balancing.
Four heterologous FARs were compared to find the highest activity and endoplasmic reticulum localization from a Mus musculus FAR. An additional twenty-one single-gene edits were screened to identify increased FAR expression; competing reactions encoded by DGA1, HFD1, and ADH6 were deleted; a mutant acetyl-CoA carboxylase was overexpressed; NADPH and carbon usage by the glutamate dehydrogenase encoded by GDH1 was limited; and the Δ9-desaturase encoded by OLE1 was overexpressed in successful strategies to improve titer. The final strain produced 1.2 g/L fatty alcohols in shake flasks, and 6.0 g/L in fed-batch fermentation, corresponding to ~ 20% of the maximum theoretical yield from glucose, the highest titers and yields reported to date in S. cerevisiae. High-level production from lignocellulosic feedstocks derived from ionic-liquid treated switchgrass and sorghum was demonstrated, reaching 0.7 g/L in shake flasks. Altogether, this work represents progress towards efficient and renewable microbial production of fatty acid-derived products.
Low yields from microbial fatty alcohol production have traditionally prevented widespread adoption, but the Berkeley Lab approach provides a more viable and sustainable source for high yield fatty alcohol production, and can allow for highly specific chemical modifications that are difficult to achieve through traditional thermochemical means. In addition, the use of lignocellulosic feedstocks derived from agricultural waste or energy crops lowers cost and provides maximal CO2 emission benefits.
DEVELOPMENT STAGE: Bench-scale testing.
STATUS: Patent pending. Available for licensing or collaborative research.
d’Espaux, L., Ghosh, A., Runguphan, W., Wehrs, M., Xu, F., Konzock, O., … Keasling, J. D. (2017). Engineering high-level production of fatty alcohols by Saccharomyces cerevisiae from lignocellulosic feedstocks. Metab Eng, 42, 115–125. https://doi.org/10.1016/j.ymben.2017.06.004
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