Biofuels Pathways Discovery Group
The Biofuels Pathways Group is focusing on the discovery of naturally occurring enzymes that, when integrated with metabolic pathways for biofuel precursors (such as fatty acids), will enable the biosynthesis of advanced biofuels in engineered host microbes.
For some advanced biofuels, such as n-butanol, the biosynthesis pathways are well established and optimization of production, rather than enzyme discovery, is required. However, for some important biofuels, discovery is needed. Our initial targets were aliphatic hydrocarbons, which are desirable biofuel targets, as they are predominant components of petroleum-based gasoline and diesel fuels and thus would be compatible with existing engines and fuel distribution systems.
At the time JBEI was founded, there were no gene sequences available for biosynthesis of non-isoprenoid aliphatic hydrocarbons (> C2). Very recently, work by several research groups, including our own, has elucidated enzymes involved in alkene biosynthesis from fatty acids (or their derivatives); we contributed the first publication in this area (Beller, Goh, and Keasling, 2010; see Figure 1 below). We are currently pursuing synthesis of other hydrocarbons and related compounds (such as diesel-range methyl ketones) by alternative pathways.
Overall, we have taken a genome-enabled approach and have studied both pure bacterial cultures and natural microbial communities known to produce the biofuels of interest. In part, gene discovery has been based on analysis of (meta)genomic, transcriptomic, or (meta)proteomic data, in silico metabolic reconstruction, and mass spectrometric assays of the activity of candidate gene products in vivo (by heterologous expression in engineered microbes) and in vitro.
