优化IPP 旁路甲羟戊酸途径和流加发酵生产大肠杆菌异戊烯醇。
Optimization of the IPP-bypass mevalonate pathway and fed-batch fermentation for the production of isoprenol in Escherichia coli.
机构信息
Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA, 94608, USA; Biological Systems & Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA, 94608, USA; Biological Systems & Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA; Department of Bioengineering, University of California, Berkeley, CA, 94720, USA; Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA; The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark; Center for Synthetic Biochemistry, Institute for Synthetic Biology, Shenzhen Institutes for Advanced Technologies, Shenzhen, China.
出版信息
Metab Eng. 2019 Dec;56:85-96. doi: 10.1016/j.ymben.2019.09.003. Epub 2019 Sep 6.
Isoprenol (3-methyl-3-buten-1-ol) is a drop-in biofuel and a precursor for commodity chemicals. Biological production of isoprenol via the mevalonate pathway has been developed and optimized extensively in Escherichia coli, but high ATP requirements and isopentenyl diphosphate (IPP) toxicity have made it difficult to achieve high titer, yield, and large-scale production. To overcome these limitations, an IPP-bypass pathway was previously developed using the promiscuous activity of diphosphomevalonate decarboxylase, and enabled the production of isoprenol at a comparable yield and titer to the original pathway. In this study, we optimized this pathway, substantially improving isoprenol production. A titer of 3.7 g/L (0.14 g isoprenol per g glucose) was achieved in batch conditions using minimal medium by pathway optimization, and a further optimization of the fed-batch fermentation process enabled an isoprenol titer of 10.8 g/L (yield of 0.105 g/g and maximum productivity of 0.157 g L h), which is the highest reported titer for this compound. The substantial increase in isoprenol titer via the IPP-bypass pathway in this study will facilitate progress toward commercialization.
异戊烯醇（3-甲基-3-丁烯-1-醇）是一种可替代的生物燃料，也是商品化学品的前体。在大肠杆菌中，通过甲羟戊酸途径生物合成异戊烯醇已经得到了广泛的开发和优化，但高 ATP 需求和异戊烯二磷酸（IPP）毒性使得难以实现高滴度、产率和大规模生产。为了克服这些限制，先前使用二磷酸甲羟戊酸脱羧酶的混杂活性开发了一种 IPP 旁路途径，该途径能够以与原始途径相当的产率和滴度生产异戊烯醇。在这项研究中，我们对该途径进行了优化，大大提高了异戊烯醇的产量。通过途径优化，在最小培养基中分批条件下达到了 3.7 g/L 的滴度（每克葡萄糖产生 0.14 g 异戊烯醇），进一步优化补料分批发酵过程使异戊烯醇的滴度达到 10.8 g/L（产率为 0.105 g/g，最大生产力为 0.157 g L h），这是该化合物的最高报道滴度。本研究中通过 IPP 旁路途径显著提高异戊烯醇的滴度将有助于推进商业化进程。
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