Cao Yujin, Mu Hui, Guo Jing, Liu Hui, Zhang Rubing, Liu Wei, Xian Mo, Liu Huizhou
1CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 China.
2Energy Research Institute, Shandong Key Laboratory of Biomass Gasification Technology, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China.
J Biol Res (Thessalon). 2020 Jan 21;27:1. doi: 10.1186/s40709-020-0111-0. eCollection 2020 Dec.
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 strain which could utilize ethanol as the sole carbon source. The alcohol dehydrogenase and aldehyde dehydrogenase from was introduced into 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 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 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.
在过去几十年中，燃料乙醇行业取得了巨大进展。乙醇可通过使用多种生物质材料作为原料进行发酵获得。然而，关于微生物利用乙醇的研究较少。通过乙烯水解容易制得的石油衍生乙醇的价格甚至低于生物乙醇。如果乙醇能够被微生物代谢以生产增值化学品，将为廉价乙醇资源的利用打开一扇新的大门。
我们构建了一种能够以乙醇作为唯一碳源的工程菌株。将来自[具体来源未提及]的乙醇脱氢酶和乙醛脱氢酶引入[具体菌株未提及]，该重组菌株获得了在乙醇上生长的能力。在葡萄糖饥饿后供应乙醇时细胞继续生长，并且在摇瓶发酵过程中进一步消耗了2.24 g/L的乙醇。然后通过异源表达甲羟戊酸的生物合成途径，将乙醇进一步用于甲羟戊酸的生产。以氘标记的乙醇-D6作为原料证实甲羟戊酸是由乙醇合成的。
本研究证明了工程菌株利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，但它可为未来构建更强大的菌株奠定基础。
