S86: Microbial Synthesis of Hydrocarbons: Towards Utilization of Lignocellulosic Biomass

Recent advances in metabolic engineering, synthetic and systems biology have led to successful engineering of microbes to produce hydrocarbon-based biofuels that can be used as “drop-in” fuels for the existing transportation infrastructure. Using tractable heterologous hosts, production of a number of hydrocarbon-based fuel substitutes or precursors has been demonstrated. These accomplishments have significantly increased our understanding of challenges encountered in producing advanced biofuels. Engineering microorganisms to produce hydrocarbon-based biofuels in suitable yields, titers, and rates at commercial scale requires significant effort in metabolic engineering. It also requires enabling and/or enhancing the microorganisms’ capability for direct utilization of the lignocellulose. One of the critical barriers for utilizing lignocellulosic biomass is the cost of hydrolytic enzymes needed to produce fermentable sugars. Many engineered microorganisms producing biofuels are either incapable of degrading cellulosic materials or degrading cellulose inefficiently, and thus the process requires addition of cellulases to generate soluble sugars.  Our approach is to develop microorganisms producing hydrocarbons and/or their precursors directly from pretreated cellulosic biomass. We are using industrially relevant strains that posses either attractive cellulolytic capabilities and/or have high capacity to synthesize hydrocarbon-rich compounds. Examples of successful synthesis of hydrocarbons using engineered alternative microorganisms capable of degrading cellulosic materials as well as heterologous expression of cellulolytic enzymes in oleaginous yeast will be presented.