In large-scale bioprocesses microbes are exposed to heterogeneous substrate availability reducing the overall process performance. A series of deletion strains was constructed from E. coli MG1655 aiming for a robust phenotype in heterogeneous fermentations with transient starvation. Deletion targets were hand-picked based on a list of genes derived from previous large-scale simulation runs. Each gene deletion was conducted on the premise of strict neutrality towards growth parameters in glucose minimal medium. The final strain of the series, named E. coli RM214, was cultivated continuously in an STR-PFR (stirred tank reactor – plug flow reactor) scale-down reactor. The scale-down reactor system simulated repeated passages through a glucose starvation zone. When exposed to nutrient gradients, E. coli RM214 had a significantly lower maintenance coefficient than E. coli MG1655 (Δm_s = 0.038 g_Glucose/g_CDW/h, p < 0.05). In an exemplary protein production scenario E. coli RM214 remained significantly more productive than E. coli MG1655 reaching 44% higher eGFP yield after 28 h of STR-PFR cultivation. This study developed E. coli RM214 as a robust chassis strain and demonstrated the feasibility of engineering microbial hosts for large-scale applications.

在大规模生物过程中，微生物暴露于异质底物可用性，降低了整体过程性能。从大肠杆菌MG1655构建了一系列缺失菌株，旨在在具有瞬时饥饿的异质发酵中获得稳健的表型。删除目标是根据从以前的大规模模拟运行中得出的基因列表精心挑选的。每个基因缺失都是在对葡萄糖基本培养基中的生长参数严格中性的前提下进行的。该系列的最终菌株，命名为大肠杆菌RM214 在 STR-PFR（搅拌釜反应器 - 活塞流反应器）按比例缩小的反应器中连续培养。缩小反应器系统模拟重复通过葡萄糖饥饿区。当暴露于养分梯度，大肠杆菌RM214有显著降低维护系数比大肠杆菌MG1655（的Δm_小号 = 0.038克_葡萄糖/克_CDW / H，P <0.05）。在示例性蛋白质生产场景中，大肠杆菌RM214 的生产力显着高于大肠杆菌MG1655，在 STR-PFR 培养 28 小时后，eGFP 产量提高了 44%。本研究开发了大肠杆菌 RM214 作为一种强大的底盘菌株，证明了工程微生物宿主用于大规模应用的可行性。