Metabolic Engineering of Saccharomyces Cerevisiae to Produce Long Chain and Medium Chain Fatty Alcohols from Xylose
Jiayuan Sheng, Weihua Guo, Xueyang Feng*
Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
Fatty alcohols are important components of a variety of industries which have a 3 billion-dollar market globally1. Long chain fatty alcohols are mainly used in surfactants, lubricants, detergents, pharmaceuticals and cosmetics while medium chain fatty alcohols could be used as diesel-like biofuels1,2. We have previously engineered a Saccharomyces cerevisiae strain to produce over 1.1 g/L 1-hexadecanol from glucose by heterogeneously expressing a bird fatty acyl-CoA reductase (FAR) and optimizing the host metabolism3. In this study we introduced a fungal xylose utilization pathway, which is composed of xylose reductase (XR), xylitol dehydrogenase (XDH), and xylulose kinase (XKS), into our engineered S. cerevisiae to produce 1-hexadecanol from xylose, a non-food feedstock. Over 0.4 g/L 1-hexadecanol can be produced by using the native xylose utilization pathway. We further optimized the xylose utilization by combinational promoter engineering and evolutionary engineering, which improved 1-hexadecanol production titer by 200% (from 0.4 g/L to 1.2 g/L). We also successfully engineered S. cerevisiae to produce 1-decanol and 1-dodecanol by introducing the FAR enzyme into the peroxisome to hijack the medium chain fatty acyl-CoA generated from the beta-oxidation pathway. To our best knowledge, this is the first time that long chain and medium chain fatty alcohols were produced in yeast from xylose.
1 Steen, E. J. et al. Microbial production of fatty-acid-derived fuels and chemicals from plant biomass. Nature 463, 559-562, doi:10.1038/nature08721 (2010).
2 Youngquist, J. T. et al. Production of medium chain length fatty alcohols from glucose in Escherichia coli. Metabolic engineering 20, 177-186, doi:10.1016/j.ymben.2013.10.006 (2013).
3 Feng, X., Lian, J. & Zhao, H. Metabolic engineering of Saccharomyces cerevisiae to improve 1-hexadecanol production. Metabolic engineering 27C, 10-19, doi:10.1016/j.ymben.2014.10.001 (2014).