(582ce) Determination of the Metabolic Pathways for Linear Hydrocarbon Biosynthesis in the Green Algae Botryococcus Braunii Strain UTEX572

The green algae Botryococcus braunii has drawn considerable interest as a potential source of drop-in biofuels due to its unique ability to accumulate high levels of hydrocarbons. Several biochemical mechanisms have been proposed for non-isoprenoid hydrocarbon biosynthesis in this and a number of other organisms, most notably the head-to-head condensation and elongation-decarboxylation pathways from fatty acid precursors, but definitive characterization of these and other possible mechanisms have largely remained elusive. In this study, structural characterization of the monoene, diene, and triene hydrocarbon classes and their fatty acid precursors in the UTEX 572 strain of B. braunii, as well as NMR and GC-MS analyses of stable isotope fed cultures, point to a likely elongation-decarboxylation biosynthetic pathway that is responsible for hydrocarbon biosynthesis. Additionally, a comparative transcriptomic analysis of hyper and hypo-hydrocarbon accumulating conditions in B. braunii has provided a potential genetic basis for the synthesis of hydrocarbons from fatty acids in this algae.