Valorization of CO2 through lithoautotrophic production of sustainable chemicals in Cupriavidus necator

Coupling recent advancements in genetic engineering of diverse microbes and gas-driven fermentation provides a path towards sustainable commodity chemical production. Cupriavidus necator H16 is a suitable species for this task because it effectively utilizes H-2 and CO2 and is genetically tractable. Here, we demonstrate the versatility of C. necator for chemical production by engineering it to produce three products from CO2 under lithotrophic conditions: sucrose, polyhydroxyalkanoates (PHAs), and lipochitooligosaccharides (LCOs). We engineered sucrose production in a co-culture system with heterotrophic growth 30 times that of WT C. necator. We engineered PHA production (20-60% DCW) and selectively altered product composition by combining different thioesterases and phaCs to produce copolymers directly from CO2. And, we engineered C. necator to convert CO2 into the LCO, a plant growth enhancer, with titers of similar to 1.4 mg/L-equivalent to yields in its native source, Bradyrhizobium. We applied the LCOs to germinating seeds as well as corn plants and observed increases in a variety of growth parameters. Taken together, these results expand our understanding of how a gas-utilizing bacteria can promote sustainable production.