SBIR Phase I: Identification of a suitable butyraldehyde/butanol dehydrogenase for a heterologously expressed butanol pathway

这个小型企业创新研究第一阶段项目将测试提议的无副产物丁醇生产主机的可行性，该主机使用分子手段来设计对醇的二次加工很重要的特定酶。生物燃料不仅有可能减少美国对对国土安全至关重要的外国石油进口的依赖，而且还可能大幅减少与全球变暖有关的温室气体排放。生物燃料，如乙醇，可以从碳基原料的转化中获得。虽然乙醇越来越多地被用作标准汽油的含氧添加剂，但丁醇在燃料方面比乙醇有几个优点。丁醇可以由与乙醇相同的原料制成，但与乙醇不同的是，丁醇有可能以与汽油相同的方式储存、运输和使用。丁醇可以使用自然产生丁醇的梭状芽孢杆菌菌株生产，但这一过程相对效率较低，并产生大量副产物。该项目将有助于开发能够将生物质转化为丁醇的微生物，其效率高于梭状芽孢杆菌，而且没有副产品。第一阶段将评估提议的无副产物丁醇生产主机的可行性。具体来说，在葡萄糖到丁醇代谢途径中催化关键步骤之一的酶将在异源宿主中表达，以确定功能最好的酶。第二阶段将在合适的生产宿主内优化代谢途径，以提高时空产量。该项目开发的技术的更广泛效益将是提供第二代可再生运输燃料的潜力，减少对进口石油的依赖，降低温室气体排放，并扩大全球农产品市场。

This Small Business Innovation Research Phase I project will test the feasibility of a proposed byproduct-free butanol-production host developed using molecular means to engineer specific enzymes important to secondary processing of the alcohols. Biofuels have the potential to not only reduce the United States' dependency on foreign oil imports vital to homeland security but to also dramatically decrease greenhouse gas emissions associated with global warming. Biofuels, such as ethanol, can be obtained from the conversion of carbon based feedstock. While ethanol is increasingly being used as an oxygenate additive for standard gasoline, butanol has several advantages over ethanol for fuel. It can be made from the same feedstocks as ethanol but, unlike ethanol, butanol has the potential of being stored, transported and used in the same manner as gasoline. Butanol can be produced using Clostridium strains that naturally produce butanol but this process is relatively inefficient and produces large amounts of byproducts. This project will aid in developing microorganisms capable of converting biomass to butanol with greater efficiency than Clostridium and without byproducts. Phase I will evaluate the feasibility of the proposed byproduct-free butanol-production host. Specifically, enzymes that catalyze one of the key steps within the glucose-to-butanol metabolic pathway will be expressed in a heterologous host to identify the one the functions best. Phase II will optimize the metabolic pathway within a suitable production host for increased space-time-yields. The broader benefits of the technology developed by this project will be the potential of providing a second generation renewable transportation fuel, reducing dependence on imported oil, lowering greenhouse gas emissions, and expanding markets for agricultural products worldwide.