The fuel ethanol industry has made tremendous progress in the last decades. Ethanol can be obtained by fermentation using a variety of biomass materials as the feedstocks. However, few studies have been conducted on ethanol utilization by microorganisms. The price of petroleum-derived ethanol, easily made by the hydrolysis of ethylene, is even lower than that of bioethanol. If ethanol can be metabolized by microorganisms to produce value-added chemicals, it will open a new door for the utilization of inexpensive ethanol resources. We constructed an engineered Escherichia coli strain which could utilize ethanol as the sole carbon source. The alcohol dehydrogenase and aldehyde dehydrogenase from Aspergillus nidulans was introduced into E. coli and the recombinant strain acquired the ability to grow on ethanol. Cell growth continued when ethanol was supplied after glucose starvation and 2.24 g L−1 of ethanol was further consumed during the shake-flasks fermentation process. Then ethanol was further used for the production of mevalonic acid by heterologously expressing its biosynthetic pathway. Deuterium-labeled ethanol-D6 as the feedstock confirmed that mevalonic acid was synthesized from ethanol. This study demonstrated the possibility of using ethanol as the carbon source by engineered E. coli strains. It can serve as the basis for the construction of more robust strains in the future though the catabolic capacity of ethanol should be further improved.

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大肠杆菌利用乙醇的代谢工程

在过去的几十年中，燃料乙醇行业取得了长足的进步。乙醇可以通过使用多种生物质材料作为原料进行发酵而获得。但是，关于微生物利用乙醇的研究很少。容易通过乙烯水解制得的石油衍生乙醇的价格甚至低于生物乙醇。如果乙醇可以被微生物代谢产生增值化学品，它将为廉价乙醇资源的利用打开新的大门。我们构建了一种工程化的大肠杆菌菌株，可以利用乙醇作为唯一的碳源。将构巢曲霉的乙醇脱氢酶和醛脱氢酶引入大肠杆菌，重组菌株获得了在乙醇上生长的能力。葡萄糖饥饿后供应乙醇时，细胞生长继续，并且在摇瓶发酵过程中进一步消耗了2.24 g L-1的乙醇。然后，通过异源表达乙醇的生物合成途径，将其进一步用于生产甲羟戊酸。氘标记的乙醇-D6作为原料证实了甲羟戊酸是由乙醇合成的。这项研究证明了工程化大肠杆菌菌株使用乙醇作为碳源的可能性。尽管乙醇的分解代谢能力应进一步提高，但它可以作为将来构建更强壮菌株的基础。然后，通过异源表达乙醇的生物合成途径，将其进一步用于生产甲羟戊酸。氘标记的乙醇-D6作为原料证实了甲羟戊酸是由乙醇合成的。这项研究证明了工程化大肠杆菌菌株使用乙醇作为碳源的可能性。尽管乙醇的分解代谢能力应进一步提高，但它可以作为将来构建更强壮菌株的基础。然后，通过异源表达乙醇的生物合成途径，将其进一步用于生产甲羟戊酸。氘标记的乙醇-D6作为原料证实了甲羟戊酸是由乙醇合成的。这项研究证明了工程化大肠杆菌菌株使用乙醇作为碳源的可能性。尽管乙醇的分解代谢能力应进一步提高，但它可以作为将来构建更强壮菌株的基础。