Evolutionary engineering is a powerful method to improve the performance of microbial cell factories, but can typically not be applied to enhance the production of chemicals due to the lack of an appropriate selection regime. We report here on a new strategy based on transcription factor-based biosensors, which directly couple production to growth. The growth of Corynebacterium glutamicum was coupled to the intracellular concentration of branched-chain amino acids, by integrating a synthetic circuit based on the Lrp biosensor upstream of two growth-regulating genes, pfkA and hisD. Modelling and experimental data highlight spatial separation as key strategy to limit the selection of ‘cheater’ strains that escaped the evolutionary pressure. This approach facilitated the isolation of strains featuring specific causal mutations enhancing amino acid production. We envision that this strategy can be applied with the plethora of known biosensors in various microbes, unlocking evolution as a feasible strategy to improve production of chemicals.

进化工程是提高微生物细胞工厂性能的有效方法，但由于缺乏适当的选择机制，通常不能用于提高化学品的生产。我们在此报告了一种基于转录因子生物传感器的新策略，该策略将生产与生长直接结合起来。通过在两个生长调节基因pfkA和hisD上游整合基于 Lrp 生物传感器的合成电路，谷氨酸棒杆菌的生长与支链氨基酸的细胞内浓度相关联. 建模和实验数据强调空间分离是限制选择逃避进化压力的“骗子”菌株的关键策略。这种方法有助于分离具有增强氨基酸生产的特定因果突变的菌株。我们设想这种策略可以应用于各种微生物中的大量已知生物传感器，将进化作为一种​​可行的策略来改善化学品的生产。