上海士锋生物利用大肠杆菌生产石油替代物新突破

生物能源是减轻碳氢化合物燃料依赖性的zui直接zui有效的方式，但是目前的生物能源（酒精和生物柴油）需要特殊的下游工艺过程，并不能*与现代的，大众市场的内燃机相容。人们渴望找到的理想的生物能源在结构和化学性质上与化石燃料相同（如不同链长的脂肪族正或异烷烃）。

本研究报道了利用大肠杆菌生产石油替代品碳氢化合物的方法。研究人员将发光杆菌（Photorhabdus luminescens）中的脂肪酸还原酶复合物与念球藻（Nostoc punctiforme）中的醛基脱羧酶偶联，可以利用游离的脂肪酸作为烷烃合成的底物，发现这种基因组合可以使得碳氢链长（Cn）和支链烷烃通过上游的脂肪酸池的基因和外源性增殖来发生合理的改变。

当在含有多种脂肪酸的组合的培养基中生长的时候，或者当修改这种大肠杆菌从而表达额外基因的时候，这种经过改造的大肠杆菌产生了在结构和化学性质上与10种零售柴油燃料的碳氢化合物分子相同的分子，而这10种零售柴油燃料通常在温带的气候条件下被使用。这些发现表明通过人工分子路径来生产可再生的工业燃料成分的方法。

Synthesis of customized petroleum-replica fuel molecules by targeted modification of free fatty acid pools in Escherichia coli

Thomas P. Howard, Sabine Middelhaufe, Karen Moore, Christoph Edner, Dagmara M. Kolak, George N. Taylor, David A. Parker, Rob Lee, Nicholas Smirnoff, Stephen J. Aves, and John Love

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.