Metabolic engineering on a 3D-printed microfluidic platform: A new approach for modular co-metabolic pathways

Metabolic engineering of cell factories often requires extensive modification of host cellular machinery, leading to numerous challenges such as metabolic burden, intermediate metabolite toxicity, and inadequate endogenous fluxes. To overcome the limitations, we presented an innovative approach for metabolic engineering, by constructing modular biosynthetic pathways on a 3D-printed microfluidic platform. Several new techniques have been developed, including novel designs of chip configurations, effective methods for enzyme immobilization on printed resins, and proper ways to regenerate cofactors in redox reactions. As a proof of concept, we built xylose consumption and CO2 fixation pathways in the microfluidic chips and successfully demonstrated that the platform was able to convert xylose and enable the rapid growth of Saccharomyces cerevisiae, which otherwise will not grow with xylose as the only carbon source. Overall, the 3D-printed microfluidic platform presents a much simpler and more efficient cell-free strategy for developing modular, optimized biosynthetic pathways.