Researchers from Exeter University, UK has developed a genetically modified strain of E. coli bacteria which can convert sugar into oil that is almost identical to conventional diesel. The engineered E. coli used genetic code from the insect pathogen Photorhabdus luminescens and from the cyanobacterium Nostoc punctiforme as well as soil microbe Bacillus subtilis to make the fuel molecules from fatty acids, along with a gene from the camphor tree—Cinamomum camphora—to cut the resulting hydrocarbon to the right length.
Professor John Love, a synthetic biologist from the University of Exeter, said: "Rather than making a replacement fuel like some bio-fuels we have made a substitute fossil fuel.
This research work is published in Applied Biological Sciences, PNAS (http://www.pnas.org/content/110/19/7636.full.pdf+html)
Synthesis of customized petroleum-replica fuel molecules by targeted modification of free fatty acid pools in Escherichia coli
"Biofuels are the most immediate, practical solution for mitigating dependence on fossil hydrocarbons, but current biofuels (alcohols and biodiesels) require significant downstream processing and are not fully compatible with modern, mass-market internal combustion engines. Rather, the ideal biofuels are structurally and chemically identical to the fossil fuels they seek to replace (i.e., aliphatic n- and iso-alkanes and -alkenes of various chain lengths). Here we report on production of such petroleum-replica hydrocarbons in Escherichia coli. The activity of the fatty acid (FA) reductase complex from Photorhabdus luminescens was coupled with aldehyde decarbonylase from Nostoc punctiforme to use free FAs as substrates for alkane biosynthesis. This combination of genes enabled rational alterations to hydrocarbon chain length (Cn) and the production of branched alkanes through upstream genetic and exogenous manipulations of the FA pool. Genetic components for targeted manipulation of the FA pool included expression of a thioesterase from Cinnamomum camphora (camphor) to alter alkane Cn and expression of the branched-chain α-keto acid dehydrogenase complex and β-keto acyl-acyl carrier protein synthase III from Bacillus subtilis to synthesize branched (iso-) alkanes. Rather than simply reconstituting existing metabolic routes to alkane production found in nature, these results demonstrate the ability to design and implement artificial molecular pathways for the production of renewable, industrially relevant fuel molecules"
