Sunday, July 24, 2011
Grand Ballroom, 5th fl (Sheraton New Orleans)
Biological hydrocarbons are a promising alternative to petroleum-based liquid transportation fuels as they would be compatible with current engines and distribution systems, yet be sourced from renewable substrates. Cyanobacteria have received significant attention because the direct conversion of sunlight and carbon dioxide to lipids will by-pass recalcitrant intermediates found in terrestrial biomass. Although it has been known for decades that some species of cyanobacteria, including Synechococcus sp. PCC7002, can synthesize hydrocarbons of different lengths, very little is known about their biosynthesis. In this study, we analyzed the hydrocarbon profile of Synechococcus sp. PCC7002 and demonstrate the involvement of a gene in the biosynthesis of two C19 α-olefins. The gene encodes a large multi-domain protein with homology to Type I polyketide synthases, suggesting a new route for hydrocarbon biosynthesis from fatty acids via an elongation-decarboxylation mechanism. The combinatorial nature of polyketide synthesis raises the possibility of using this type of genes to produce a wide range of industrially relevant α-olefins and high value chemical building blocks.