Heterologous expression of formate dehydrogenase enables photoformatotrophy in the emerging model microalga, Picochlorum renovo

Lukas R Dahlin; Alex W Meyers; Skylar W Stefani; Ellsbeth G Webb; Benton Wachter; Venkataramanan Subramanian; Michael T Guarnieri

doi:10.3389/fbioe.2023.1162745

Heterologous expression of formate dehydrogenase enables photoformatotrophy in the emerging model microalga, Picochlorum renovo

Front Bioeng Biotechnol. 2023 Aug 29:11:1162745. doi: 10.3389/fbioe.2023.1162745. eCollection 2023.

Authors

Lukas R Dahlin¹, Alex W Meyers¹, Skylar W Stefani¹, Ellsbeth G Webb¹, Benton Wachter¹, Venkataramanan Subramanian¹, Michael T Guarnieri^{1

2

3}

Affiliations

¹ Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States.
² Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, United States.
³ Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO, United States.

Abstract

Rising global greenhouse gas emissions and the impacts of resultant climate change necessitate development and deployment of carbon capture and conversion technologies. Amongst the myriad of bio-based conversion approaches under evaluation, a formate bio-economy has recently been proposed, wherein CO₂-derived formate serves as a substrate for concurrent carbon and energy delivery to microbial systems. To date, this approach has been explored in chemolithotrophic and heterotrophic organisms via native or engineered formatotrophy. However, utilization of this concept in phototrophic organisms has yet to be reported. Herein, we have taken the first steps to establish formate utilization in Picochlorum renovo, a recently characterized eukaryotic microalga with facile genetic tools and promising applied biotechnology traits. Plastidial heterologous expression of a formate dehydrogenase (FDH) enabled P. renovo growth on formate as a carbon and energy source. Further, FDH expression enhanced cultivation capacity on ambient CO₂, underscoring the potential for bypass of conventional CO₂ capture and concentration limitations. This work establishes a photoformatotrophic cultivation regime that leverages light energy-driven formate utilization. The resultant photosynthetic formate platform has widespread implications for applied phototrophic cultivation systems and the bio-economy at large.

Keywords: formate; formate bio-economy; formate dehydrogenase; microalgae; photoformatotrophy; phototroph; picochlorum.

Grants and funding

This work was authored by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DEAC36-08GO28308. Funding was provided by the Laboratory Directed Research and Development (LDRD) Program at NREL, the Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE), Algae Biotechnology Partnership, under Agreement No. 28812, the Office of Fossil Energy and Carbon Management, under award No. DE-FE0032186, and Office of Science, Office of Biological and Environmental Research, Genomic Science Program under Secure Biosystems Design Science Focus Area IMAGINE BioSecurity: Integrative Modeling and Genome-scale Engineering for Biosystems Security, under contract number DEAC36-08GO28308.