11月15日，据《每日邮报》网站报道题：大多数糖变为生物柴油？肠胃中的大肠杆菌可能会在将植物变为无限的生物燃料方面发挥关键作用。
生物柴油常被誉为可能减轻我们依赖矿物燃料的解决之道。
用植物或用过的烹调油制成的生物柴油较为浓稠，化学性质与我们目前使用的矿物燃料相似，因此，易于在大型引擎中使用。
火车、汽车甚至飞机已经在使用这种燃料。
但是，大多数使用生物柴油的交通工具用的是经过再加工的烹调油———这种油过于昂贵和稀少，无法大规模商用。
为了让生物柴油真正产生影响力，必须使之直接来自植物。
如今，美国斯坦福大学的研究人员说，产生廉价而且基于植物的生物柴油的化学过程可能即将被发现。
最近用大肠杆菌进行的实验表明，这种细菌可能是关键所在。大肠杆菌在哺乳动物的肠道内很常见，有些菌株会引起食物中毒。
用植物生产生物柴油是一个复杂的过程，迄今为止，尚未有用植物油大规模生产这种柴油的可行方法。
大肠杆菌能将植物中的糖转化为脂肪酸衍生物———一种与肥皂类似的化学物，也是具有生产一种可加工燃料的前身。
但科学家们此前不确定这种细菌是否有足够的化学“能量”来实现商业生产。
斯坦福大学教授柴坦·科斯拉对将糖转化为脂肪酸衍生物的大肠杆菌的数量在理论上是否有“限制”进行了研究。也就是说，这种细菌是否真的具有用普通植物生产燃料的能力。
《国家科学院院刊》（PNAS）月刊上刊登的一篇研究报告称，答案似乎是肯定的。
科斯拉说：“好消息是，在大肠杆菌中产生脂肪酸的‘引擎’强大得令人难以置信。它能以一种非凡的速度将糖转化为燃料。”（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.
