11月15日,，據(jù)《每日郵報》網(wǎng)站報道題：大多數(shù)糖變?yōu)樯锊裼?？腸胃中的大腸桿菌可能會在將植物變?yōu)闊o限的生物燃料方面發(fā)揮關(guān)鍵作用。
生物柴油常被譽為可能減輕我們依賴礦物燃料的解決之道,。
用植物或用過的烹調(diào)油制成的生物柴油較為濃稠,，化學性質(zhì)與我們目前使用的礦物燃料相似，因此,，易于在大型引擎中使用,。
火車、汽車甚至飛機已經(jīng)在使用這種燃料,。
但是,，大多數(shù)使用生物柴油的交通工具用的是經(jīng)過再加工的烹調(diào)油———這種油過于昂貴和稀少，無法大規(guī)模商用,。
為了讓生物柴油真正產(chǎn)生影響力,，必須使之直接來自植物。
如今,，美國斯坦福大學的研究人員說,，產(chǎn)生廉價而且基于植物的生物柴油的化學過程可能即將被發(fā)現(xiàn)。
最近用大腸桿菌進行的實驗表明,，這種細菌可能是關(guān)鍵所在,。大腸桿菌在哺乳動物的腸道內(nèi)很常見，有些菌株會引起食物中毒,。
用植物生產(chǎn)生物柴油是一個復雜的過程,，迄今為止，尚未有用植物油大規(guī)模生產(chǎn)這種柴油的可行方法,。
大腸桿菌能將植物中的糖轉(zhuǎn)化為脂肪酸衍生物———一種與肥皂類似的化學物,，也是具有生產(chǎn)一種可加工燃料的前身。
但科學家們此前不確定這種細菌是否有足夠的化學“能量”來實現(xiàn)商業(yè)生產(chǎn),。
斯坦福大學教授柴坦·科斯拉對將糖轉(zhuǎn)化為脂肪酸衍生物的大腸桿菌的數(shù)量在理論上是否有“限制”進行了研究,。也就是說，這種細菌是否真的具有用普通植物生產(chǎn)燃料的能力。
《國家科學院院刊》（PNAS）月刊上刊登的一篇研究報告稱,，答案似乎是肯定的,。
科斯拉說：“好消息是，在大腸桿菌中產(chǎn)生脂肪酸的‘引擎’強大得令人難以置信,。它能以一種非凡的速度將糖轉(zhuǎn)化為燃料,。”（生物谷 Bioon.com）
doi:10.1073/pnas.1110852108
PMC:
PMID:
In vitro reconstitution and steady-state analysis of the fatty acid synthase from Escherichia coli
作者：Hiroyasu Yamamoto, Evan G. Williams, Laurent Mouchiroud, Carles Cantó, Weiwei Fan, Michael Downes, Christophe Héligon, Grant D. Barish, Béatrice Desvergne, Ronald M. Evans et al.
Microbial fatty acid derivatives are emerging as promising alternatives to fossil fuel derived transportation fuels. Among bacterial fatty acid synthases (FAS), the Escherichia coli FAS is perhaps the most well studied, but little is known about its steady-state kinetic behavior. Here we describe the reconstitution of E. coli FAS using purified protein components and report detailed kinetic analysis of this reconstituted system. When all ketosynthases are present at 1 μM, the maximum rate of free fatty acid synthesis of the FAS exceeded 100 μM/ min. The steady-state turnover frequency was not significantly inhibited at high concentrations of any substrate or cofactor. FAS activity was saturated with respect to most individual protein components when their concentrations exceeded 1 μM. The exceptions were FabI and FabZ, which increased FAS activity up to concentrations of 10 μM; FabH and FabF, which decreased FAS activity at concentrations higher than 1 μM; and holo-ACP and TesA, which gave maximum FAS activity at 30 μM concentrations. Analysis of the S36T mutant of the ACP revealed that the unusual dependence of FAS activity on holo-ACP concentration was due, at least in part, to the acyl-phosphopantetheine moiety. MALDI-TOF mass spectrometry analysis of the reaction mixture further revealed medium and long chain fatty acyl-ACP intermediates as predominant ACP species. We speculate that one or more of such intermediates are key allosteric regulators of FAS turnover. Our findings provide a new basis for assessing the scope and limitations of using E. coli as a biocatalyst for the production of diesel-like fuels.
