The aim of this study was to establish isobutanol production on chemically defined medium in Escherichia coli. By individually expressing each gene of the pathway, we constructed a plasmid library for isobutanol production. Strain screening on chemically defined medium showed successful production in the robust E. coli W strain, and expression vector IB 4 was selected as the most promising construct due to its high isobutanol yields and efficient substrate uptake. The investigation of different aeration strategies in combination with strain improvement and the implementation of a pulsed fed-batch were key for the development of an efficient production process. E. coli W ΔldhA ΔadhE Δpta ΔfrdA enabled aerobic isobutanol production at 38% of the theoretical maximum. Use of cheese whey as raw material resulted in longer process stability, which allowed production of 20 g l⁻¹ isobutanol. Demonstrating isobutanol production on both chemically defined medium and a residual waste stream, this study provides valuable information for further development of industrially relevant isobutanol production processes.

这项研究的目的是建立在化学上确定的大肠杆菌中异丁醇的生产。通过单独表达该途径的每个基因，我们构建了用于异丁醇生产的质粒文库。在化学成分确定的培养基上进行菌株筛选显示，该菌株可在强大的大肠杆菌W菌株中成功生产，并且由于其高异丁醇收率和有效的底物吸收，选择了表达载体IB 4作为最有前途的构建体。研究不同的曝气策略，并结合应变的改善和脉冲补料的实施是开发高效生产工艺的关键。大肠杆菌W¯¯ ΔldhAΔadhEΔptaΔfrdA使有氧异丁醇的产量达到理论最大值的38％。使用干酪乳清作为原料导致更长的工艺稳定性，这允许生产20 g l ^-1异丁醇。该研究证明了在化学成分确定的介质和残留废物流上的异丁醇生产，该研究为工业相关异丁醇生产工艺的进一步发展提供了有价值的信息。