Systems biology of the butanol-producing Clostridium acetobutylicum: new source of biofuel and chemicals/COSMIC2

到2030年，全球能源消费预计将增长57%。化石燃料无法满足这一需求，因为它们的持续使用正在导致全球变暖，而且无论如何，它们都是有限的储备，将在本世纪末之前耗尽。从天然植物材料(生物燃料)中提取的液体燃料是交通运输部门最有前途的替代能源。在这方面，一种名为丁醇的酒精目前正受到相当大的兴趣，因为它比乙醇和生物柴油具有更好的性能。丁醇具有比乙醇更高的能量含量，可以利用现有的汽油供应和分销渠道，可以与汽油以更高的浓度混合，而无需修改发动机，提供更好的燃油经济性，并与乙醇不同，具有作为航空燃料的潜力。传统上，丁醇是由一种名为乙酰丁酸梭菌的细菌在含有糖的生长介质上生长时产生的。发酵过程被称为丙酮-丁醇-乙醇(ABE)过程。在上个世纪上半叶，ABE工艺的重要性/规模仅次于从酵母中生产乙醇。然而，随着石化工业的出现，这一过程变得不经济，从20世纪60年代起在西方世界被抛弃。这一流程最近在中国和巴西重新建立起来，在那里，较低的运营成本使基于20世纪低效技术的流程变得经济。要在西方世界采用，需要一个更有效的过程。它的派生将依赖于对所用细菌菌株的改进。然而，这些菌株的合理产生将需要更详细地了解细胞内催化和控制发酵产物形成的复杂过程。更好地了解这一进程是本提案的总体目标。为此，将使用一种名为系统生物学的新的整体方法，它包括数学建模和实验测试的迭代周期。这是由于在前一轮筹资中取得的进展，在该轮筹资中开发了关键的基因工具和方法，使其能够对选定的基因进行精确的改变并评估后果。

By 2030, worldwide energy consumption is projected to grow by 57%. Fossil fuels cannot meet this demand, as their continued use is causing global warming and they are in any case a finite reserve that will be exhausted before the end of this century. Liquid fuels derived from natural plant material (biofuels), are the most promising alternative energy source for use in the transportation sector. In this regard, an alcohol called butanol is currently receiving considerable interest due to its superior properties compared to ethanol and biodiesel. Butanol has a higher energy content than ethanol, can make use of existing petrol supply and distribution channels, can be blended with petrol at higher concentrations without engine modification, offers better fuel economy and has, unlike ethanol, potential as aviation fuel. Traditionally, butanol is produced by a bacterium called Clostridium acetobutylicum when growing on growth media containing sugars. The fermentation process is known as the Acetone-Butanol-Ethanol (ABE) process. In the first half of the last century, the ABE process was second in importance/scale only to ethanol production from yeast. However, with the advent of the petrochemical industry, the process became uneconomic and was abandoned in the western world from the 1960s onwards. The process has recently been re-established in China and Brazil, where lower operating costs make a process based on inefficient 20th century technology economic. For adoption in the western world, a more efficient process is required. Its derivation will be reliant on improvements to the bacterial strains employed. However, the rational creation of such strains will require a more detailed understanding of the complex processes within the cell that catalyse and control the formation of fermentation products. Deriving a better understanding of the process is the overall objective of this proposal. For this, a new holistic approach termed systems biology will be used, which involves iterative cycles of mathematical modelling and experimental testing. It is made possible by developments made in an earlier funding round in which crucial gene tools and methodologies were developed that will allow precise changes to be made to selected genes and the consequences assessed.