Progress towards a new model chemolithoautotrophic host

Some of the largest scale chemical processes for the production of important commodity chemicals and fuels involve an H2-containing gas mixture as an intermediate [e.g. ammonia, urea, methanol, FischerTropsch (F-T) diesel, and hydrotreatment of crude petroleum to refined fuels]. The successful
development of a model H2-oxidizing chemoautotrophic host could expand the range of fuels and
chemicals produced from H2 and CO2 intermediates in the chemical, oil, and gas sectors in the near
term, as well as from renewable and waste-derived sources of these gases that are expected to greatly
expand in coming years.

Among non-photosynthetic bacteria that can utilize H2 and CO2, Cupriavidus necator (C. necator,
formerly Ralstonia eutropha), is the best studied. C. necator is an excellent microbial host for the
production of a variety of chemicals because it grows extremely quickly to very high cell densities
autotrophically on H2 and CO2, is genetically tractable, and has the ability to accumulate polymers, such as polyhydroxybutyrate, at industrial levels. Despite having great potential as a platform bioproduction host, genetic tools are limited, making metabolic engineering of this organism slow and laborious. With the joint efforts from experienced researchers from Lawrence Berkeley National Laboratory (LBNL), National Renewable Energy Laboratory (NREL), Oak Ridge National Laboratory (ORNL), and Kiverdi, Inc., we will develop a suite of next-generation genetic tools to rapidly and efficiently engineer C. necator, enabling the construction of strains capable of producing value-added chemicals and biofuels from CO2 and renewable H2 feedstocks at non-prohibitive costs. As a concrete demonstration of this proposed platform’s potential capabilities, we will engineer C. necator to convert H2 and CO2 into a fatty acid derived molecule commonly used as a bioproduct currently sourced from palm kernel oil, the cultivation of which is associated with widespread rainforest destruction.

Relevant ABF Capabilities

Project Partners: Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory, National Renewable Energy Laboratory, Kiverdi

Contacts: Steven Singer, Lawrence Berkeley National Laboratory; Adam Guss,
Oak Ridge National Laboratory); Carrie Eckert); John
Reed, Kiverdi

Performance period: 10/1/18-9/30/20