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

Abstract

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 H2 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 ~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.