Wheeldon Ian, Christopher Phillip, Blanch Harvey
Chemical and Environmental Engineering, University of California Riverside, Riverside, CA 92521, United States.
Chemical and Environmental Engineering, University of California Riverside, Riverside, CA 92521, United States.
Curr Opin Biotechnol. 2017 Jun;45:127-135. doi: 10.1016/j.copbio.2017.02.019. Epub 2017 Mar 30.
The past decade has seen significant government and private investment in fundamental research and process development for the production of biofuels and chemicals from lignocellulosic biomass-derived sugars. This investment has helped create new metabolic engineering and synthetic biology approaches, novel homogeneous and heterogeneous catalysts, and chemical and biological routes that convert sugars, lignin, and waste products such as glycerol into hydrocarbon fuels and valuable chemicals. With the exception of ethanol, economical biofuels processes have yet to be realized. A potentially viable way forward is the integration of biological and chemical catalysis into processes that exploit the inherent advantages of each technology while circumventing their disadvantages. Microbial fermentation excels at converting sugars from low-cost raw materials streams into simple alcohols, acids, and other reactive intermediates that can be condensed into highly reduced, long and branched chain hydrocarbons and other industrially useful compounds. Chemical catalysis most often requires clean feed streams to avoid catalyst deactivation, but the chemical and petroleum industries have developed large scale processes for C-C coupling, hydrogenation, and deoxygenation that are driven by low grade heat and low-cost feeds such as hydrogen derived from natural gas. In this context, we suggest that there is a reasonably clear route to the high yield synthesis of biofuels from biomass- or otherwise derived-fermentable sugars: the microbial production of reactive intermediates that can be extracted or separated into clean feed stream for upgrading by chemical catalysis. When coupled with new metabolic engineering strategies that maximize carbon and energy yields during fermentation, biomass-to-fuels processes may yet be realized.
在过去十年中，政府和私人对从木质纤维素生物质衍生的糖生产生物燃料和化学品的基础研究和工艺开发进行了大量投资。这笔投资有助于创造新的代谢工程和合成生物学方法、新型均相和多相催化剂，以及将糖、木质素和甘油等废物转化为烃类燃料和有价值化学品的化学和生物途径。除了乙醇之外，经济可行的生物燃料工艺尚未实现。一个潜在可行的前进方向是将生物催化和化学催化整合到利用每种技术固有优势同时规避其劣势的工艺中。微生物发酵擅长将低成本原料流中的糖转化为简单的醇、酸和其他反应性中间体，这些中间体可以缩合为高度还原的、长链和支链烃以及其他工业上有用的化合物。化学催化通常需要纯净的进料流以避免催化剂失活，但化学工业和石油工业已经开发出由低品位热量和低成本进料（如来自天然气的氢气）驱动的大规模碳 - 碳偶联、氢化和脱氧工艺。在这种背景下，我们认为从生物质或其他来源的可发酵糖高产合成生物燃料有一条相当清晰的途径：微生物生产可提取或分离成纯净进料流以通过化学催化进行升级的反应性中间体。当与在发酵过程中最大化碳和能量产率的新代谢工程策略相结合时，生物质到燃料的工艺可能仍可实现。
