Kinetic compartmentalization by unnatural reaction for itaconate production

Unlike eukaryotic system, bacterial hosts lack membranous system, which is one of the limitations for efficient metabolic engineering. Here, the authors report a kinetic compartmentalization strategy to increase substrate availability from competitive reactions for the efficient production of itaconate in E. coli. Physical compartmentalization of metabolism using membranous organelles in eukaryotes is helpful for chemical biosynthesis to ensure the availability of substrates from competitive metabolic reactions. Bacterial hosts lack such a membranous system, which is one of the major limitations for efficient metabolic engineering. Here, we employ kinetic compartmentalization with the introduction of an unnatural enzymatic reaction by an engineered enzyme as an alternative strategy to enable substrate availability from competitive reactions through kinetic isolation of metabolic pathways. As a proof of concept, we kinetically isolate the itaconate synthetic pathway from the tricarboxylic acid cycle in Escherichia coli, which is natively separated by mitochondrial membranes in Aspergillus terreus. Specifically, 2-methylcitrate dehydratase is engineered to alternatively catalyze citrate and kinetically secure cis-aconitate for efficient production using a high-throughput screening system. Itaconate production can be significantly improved with kinetic compartmentalization and its strategy has the potential to be widely applicable.

Automated summary

Unlike eukaryotic systems, bacterial hosts lack a membranous system, which is a limitation for efficient metabolic engineering. In this study, a kinetic compartmentalization strategy was used to increase substrate availability from competitive reactions for the efficient production of itaconate in E. coli.