Valorization of CO₂through lithoautotrophic production of sustainable chemicals inCupriavidus 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 H 2 and CO 2 and is genetically tractable. Here, we demonstrate the versatility of C. necator for chemical production by engineering it to produce three products from CO 2 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 CO 2 . And, we engineered C. necator to convert CO 2 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

Metabolic Engineering of Cupriavidus necator H16 for Sustainable Biofuels from CO2

“…C. necator also has a natural biosynthetic route to produce the carbon-dense biopolymer poly[(R)-3 hydroxybutyrate] (PHB), a biodegradable plastic-like molecule that is stored in granules during nutrient limitation with titers that can exceed 70% of total biomass by dry weight (Figure 1) [12]. Carbon flux can be diverted away from PHB synthesis in several cases to generate value-added products, such as isobutanol, methyl ketones, isoprenoids, sucrose, modified PHBs, growth enhancers for plants, and a further variety of carbon-dense compounds and commodity chemicals [10,[13][14][15][16][17]. C. necator can also grow on photovoltaic-derived electricity by H 2 and O 2 created by water splitting through indirect electron Glossary 2-phosphoglycolate (2-PG): a waste product of the nonspecific activity of rubisco towards oxygen.…”

From gas to sugar: Trehalose production inCupriavidus necatorfrom CO2and hydrogen gas

“…While finalizing this manuscript for publication, we noticed a similar study had been published on bioRxiv (Nangle et al, 2020) in which, among other products, sucrose was produced from a gaseous mixture by expression of sucrose synthesis genes and a sucrose porin. Sugar produced from CO2 was successfully used to feed heterotrophic processes as shown by Nangle et al and former studies (Ducat et al, 2012;Löwe et al, 2017), but this biotechnologically produced sugar (by S. elongatus or C. necator) will likely be too expensive in the beginning in a commercial setting.…”

Trehalose production by Cupriavidus necator from CO2 and hydrogen gas

“…From gas to sugar: Trehalose production in Cupriavidus necator from CO2 and hydrogen gas While finalizing this manuscript for publication, we noticed a similar study had been published on bioRxiv (Nangle et al, 2020) in which, among other products, sucrose was produced from a gaseous mixture by expression of sucrose synthesis genes and a sucrose porin. Sugar produced from CO2 was successfully used to feed heterotrophic processes as shown by Nangle et al and former studies (Ducat et al, 2012;Löwe et al, 2017), but this biotechnologically produced sugar (by S. elongatus or C. necator) will likely be too expensive in the beginning in a commercial setting.…”