Synthetic Genetic Elements Enable Rapid Characterization of Inorganic Carbon Uptake Systems in Cupriavidus necator H16.

Cupriavidus necator H16 is a facultative chemolithotroph capable of using CO2 as a carbon source, making it a promising organism for carbon-negative biomanufacturing of petroleum-based product alternatives. In contrast to model microbes, genetic engineering technologies are limited in C. necator, constraining its utility in basic and applied research. Here, we developed a genome engineering technology to efficiently mobilize, integrate, and express synthetic genetic elements (SGEs) in C. necator. We tested the chromosomal expression of four inducible promoters to optimize an engineered genetic landing pad for tunable gene expression. To demonstrate utility, we employed the SGE system to design, mobilize, and express eight heterologous inorganic carbon uptake pathways in C. necator. We demonstrated all inorganic carbon uptake systems' upregulated intracellular bicarbonate concentrations under heterotrophic conditions. This work establishes the utility of the SGE strategy for expedited integration and tunable expression of heterologous pathways, and enhances intracellular bicarbonate concentrations in C. necator.