Outlook for developing a direct microbial conversion platform for hydrocarbon fuel production from lignocellulosic biomass using Yarrowia lipolytica

Oleaginous yeasts are promising organisms for producing hydrocarbon fuel precursors from biomass sugars.  We investigated the potential of a direct microbial conversion (DMC) platform for producing hydrocarbon fuels from lignocellulosic biomass by expressing heterologous cellulase and xylanase genes in Yarrowia lipolytica.  Y. lipolytica is known as an oleaginous microorganism that accumulates lipids intracellularlly and is capable of metabolizing glucose and xylose to produce lipids.  However, it lacks biomass degrading enzymes and consequently cannot directly utilize lignocellulosic substrates as a carbon source. To reduce costly purchase or separate production of the cell wall degrading enzymes required to produce fermentable sugars, we expressed several key glycoside hydrolases, including cellobiohydrolase I (CBH I), endoglucanase II (EGII), and an exoxylanase in Y. lipolytica and showed that these enzymes were fully active.  In this presentation, we will outline the key findings for recombinant Y. lipolytica which support its use for direct microbial production of hydrocarbon fuels.