Scientists have used E. coli to break down switchgrass before, but this is the first time that researchers have been able to use a specific strain to break down switchgrass into usable molecules of the three most-popular fuels in the world. Once the broken down sugers are extracted, they can be turned into usable, renewable fuels.
I wish I understood this stuff in a way that I could break it up into easier-to-digest tidbits. What I can say is that the researchers were able to create Bioethanol, butonal, and pinene (a pre-cursor to jet fuel) using E. coli and pre-treatment of switchgrass with ionic liquids. I’ve posted the “official” explanation below from one of the researchers, Gregory Bokinsk, for those of you with more brain power than I to decipher. Either way though, I think it is a very cool development.
One approach to reducing the costs of advanced biofuel production from cellulosic biomass is to engineer a single microorganism to both digest plant biomass and produce hydrocarbons that have the properties of petrochemical fuels. Such an organism would require pathways for hydrocarbon production and the capacity to secrete sufficient enzymes to efficiently hydrolyze cellulose and hemicellulose. To demonstrate how one might engineer and coordinate all of the necessary components for a biomass-degrading, hydrocarbon-producing microorganism, we engineered a microorganism naïve to both processes, Escherichia coli, to grow using both the cellulose and hemicellulose fractions of several types of plant biomass pretreated with ionic liquids. Our engineered strains express cellulase, xylanase, beta-glucosidase, and xylobiosidase enzymes under control of native E. coli promoters selected to optimize growth on model cellulosic and hemicellulosic substrates.
Furthermore, our strains grow using either the cellulose or hemicellulose components of ionic liquid-pretreated biomass or on both components when combined as a co-culture. Both cellulolytic and hemicellulolytic strains were further engineered with three biofuel synthesis pathways to demonstrate the production of fuel substitutes or precursors suitable for gasoline, diesel, and jet engines directly from ionic liquid-treated switchgrass without externally supplied hydrolase enzymes.
This demonstration represents a major advance toward realizing a consolidated bioprocess. With improvements in both biofuel synthesis pathways and biomass digestion capabilities, our approach could provide an economical route to production of advanced biofuels.