Thermophilic Systems for Production of Ethanol and Other Neutral Products from Lignocellulose

这项研究的目的是利用嗜热菌， 将木质纤维素材料转化为乙醇和其他中性 产品. 考虑了两个任务，每个任务都基于原始分析 和/或概念。 这些任务涉及限制 高温溶剂生产的应用，并预计 促进对几个主题的基本理解 在生物化学工程和应用微生物学和生物化学。 第一个任务使用连续纯培养来研究 产品操作对终产物代谢顺序影响 评估这种方法的应用潜力， 代谢调节的理论模型。 第二个任务是扩展 产品操作的实验和理论研究， 未定义的混合文化。 木质纤维素生物转化为乙醇和其它溶剂 是一种通用的工艺，可用于各种应用， 取代石油。 美国可获得的木质纤维素的量。 远远超过玉米和其他农作物的产量， 并且足够大，运输燃料需求可以 从这个资源中得到满足。 嗜热菌对 因为它们可以发酵所有的碳水化合物 生物质的成分。 这一特点对 过程经济学，并区分嗜热菌与其他 已被考虑用于溶剂生产的生物制剂。 这项研究解决了嗜热菌的一个主要局限性， 用于溶剂生产：有机酸的生产。 生化 考虑建议修改发酵罐环境， 有利于溶剂生产和生物反应器设计，以实现这些 修改. 研究环境影响的实验 溶剂生产的因素将进行纯和 未定义的混合文化。 溶剂生产的研究 未定义的混合文化可能会导致一个新的进程， 厌氧消化的优点，但生产溶剂代替 价值较低的甲烷。 稀酸预处理硬木和木糖 将是研究的主要底物。

This research is directed toward using thermophilic bacteria to convert lignocellulosic materials into ethanol and other neutral products. Two tasks are considered, each based on original analyses and/or concepts. These tasks address critical factors which limit the application of thermophilic solvent production, and are also expected to contribute to fundamental understanding relevant to several topics in biochemical engineering and applied microbiology and biochemistry. The first task uses continuous pure cultures to investigate the influence of product manipulation on end product metabolism in order to evaluate both the applied potential of this approach and also theoretical models for metabolic regulation. The second task extends experimental and theoretical investigation of product manipulation to undefined mixed cultures. Biological conversion of lignocellulose to ethanol and other solvents is a versatile process which could be used in various applications to replace petroleum. The amount of lignocellulose available in the U.S. is much greater than the amounts of corn and other agricultural crops, and is sufficiently large that transportation fuel requirements could be met from this resource. Thermophilic bacteria are attractive for solvent production because they can ferment all of the carbohydrate components in biomass. This feature has a very favorable impact on process economics, and distinguishes thermophiles from other biological agents which have been considered for solvent production. This research addresses one of the main limitations of thermophiles for solvent production: The production of organic acids. Biochemical considerations suggest modifications of the fermentor environment to favor solvent production, and bioreactor designs to achieve these modifications. Experiments to investigate effects of environmental factors on solvent production will be carried out with both pure and undefined mixed cultures. The study of solvent production by undefined mixed cultures could result in a new process having many of the advantages of anaerobic digestion but producing solvents in lieu of less valuable methane. Dilute-acid pretreated hardwood and xylose will be the major substrates studied.