Alcohol and hydrogen metabolism of hyperthermophilic microorganisms

该研究的长期目标是表征新型耐热酒精脱氢酶和加氢酶，并揭示它们作为生产乙醇和氢作为生物燃料的关键酶的作用和潜在应用。超嗜热菌具有在90℃及以上温度下生长的显著特性，它们能够代谢碳水化合物，包括各种生物聚合物和一些废物，产生乙醇和氢。然而，关于所有的酶和它们的代谢调节，以及涉及到酒精和氢的超嗜热生产的代谢途径的知识非常有限。这项研究的目的之一是研究从包括甘油在内的碳水化合物（生物柴油生产的副产品）生产酒精和氢的机制。将研究不同生长条件下乙醇和氢气的生产调控，并利用二维凝胶电泳和生化分析以及分子探针研究代谢途径中涉及的关键酶的鉴定。这些酶将被纯化，并利用酶分析和三维结构测定等技术对其催化和生物物理性质进行表征。利用可用于超嗜热菌的分子技术，优化酒精和氢气的生产。本研究中使用的微生物包括细菌（Thermotoga maritima, Tmax =90°C， T. petrophila, Tmax =88°C）和古细菌（Thermococcus guaymasensis, Tmax =90°C， T. kodakarensis KOD1, Tmax =100°C）的代表。这项研究的成功完成将提供关于超嗜热酒精和氢代谢的进一步信息，并阐明在接近100°C的温度下的代谢途径。此外，所获得的结果将为构建替代的和更有效的生产生物燃料乙醇和氢的系统提供关键信息，以及关于超嗜热酶和中温酶之间进化关系的新信息。

The long-term goal of the proposed research is to characterize novel thermostable alcohol dehydrogenases and hydrogenases, and to reveal their roles and potential applications as key enzymes for the production of alcohol and hydrogen as biofuels. Hyperthermophiles have a remarkable property of growing at temperatures of 90°C and above, and they are capable of metabolizing carbohydrates including various biopolymers and some waste materials to produce ethanol and hydrogen. However, there is very limited knowledge about all the enzymes and their metabolic regulation as well as metabolic pathways involved in the hyperthermophilic production of alcohol and hydrogen. One of the objectives of the research is to investigate the mechanisms of alcohol and hydrogen production from carbohydrates including glycerol, a by-product of biodiesel manufacture. The regulation of the production of ethanol and hydrogen will be studied under various growth conditions, and the identification of key enzymes involved in the metabolic pathways will be investigated using two-dimensional gel electrophoresis and biochemical analysis as well as molecular probes. The enzymes will be purified and characterized with respect to their catalytic and biophysical properties using techniques including enzymatic analyses and three-dimensional structural determination. The optimization of the production of alcohol and hydrogen will be achieved using molecular techniques available for hyperthermophiles. The microorganisms to be used in this study include representatives from the domains of Bacteria (Thermotoga maritima, Tmax =90°C, and T. petrophila, Tmax =88°C) and Archaea (Thermococcus guaymasensis, Tmax =90°C, and T. kodakarensis KOD1, Tmax =100°C). Successful completion of this research will provide further information about the hyperthermophilic alcohol and hydrogen metabolism, and elucidate the metabolic pathways at temperatures near 100°C. Furthermore, the results obtained will provide key information in the construction of alternative and more efficient systems for the production of biofuels alcohol and hydrogen, as well as new information on the evolutionary relationships between hyperthermophilic and mesophilic enzymes.