Fischer Curt R, Klein-Marcuschamer Daniel, Stephanopoulos Gregory
Department of Chemical Engineering, Massachusetts Institute of Technology, Room 56-469, Cambridge, MA 02139, USA.
Metab Eng. 2008 Nov;10(6):295-304. doi: 10.1016/j.ymben.2008.06.009. Epub 2008 Jul 3.
Currently, the predominant microbially produced biofuel is starch- or sugar-derived ethanol. However, ethanol is not an ideal fuel molecule, and lignocellulosic feedstocks are considerably more abundant than both starch and sugar. Thus, many improvements in both the feedstock and the fuel have been proposed. In this paper, we examine the prospects for bioproduction of four second-generation biofuels (n-butanol, 2-butanol, terpenoids, or higher lipids) from four feedstocks (sugars and starches, lignocellulosics, syngas, and atmospheric carbon dioxide). The principal obstacle to commercial production of these fuels is that microbial catalysts of robust yields, productivities, and titers have yet to be developed. Suitable microbial hosts for biofuel production must tolerate process stresses such as end-product toxicity and tolerance to fermentation inhibitors in order to achieve high yields and titers. We tested seven fast-growing host organisms for tolerance to production stresses, and discuss several metabolic engineering strategies for the improvement of biofuels production.
目前，微生物产生的主要生物燃料是淀粉或糖衍生的乙醇。然而，乙醇并非理想的燃料分子，且木质纤维素原料比淀粉和糖丰富得多。因此，人们提出了许多在原料和燃料方面的改进措施。在本文中，我们研究了利用四种原料（糖和淀粉、木质纤维素、合成气以及大气中的二氧化碳）生物生产四种第二代生物燃料（正丁醇、2-丁醇、萜类化合物或高级脂质）的前景。这些燃料商业化生产的主要障碍在于，尚未开发出具有高产率、高生产力和高滴度的微生物催化剂。用于生物燃料生产的合适微生物宿主必须耐受诸如终产物毒性和对发酵抑制剂的耐受性等工艺压力，以便实现高产率和高滴度。我们测试了七种快速生长的宿主生物体对生产压力的耐受性，并讨论了几种用于提高生物燃料产量的代谢工程策略。
