AUTHOR=Kim Seohyoung , Giraldo Néstor , Rainaldi Vittorio , Machens Fabian , Collas Florent , Kubis Armin , Kensy Frank , Bar-Even Arren , Lindner Steffen N. 

TITLE=Optimizing E. coli as a formatotrophic platform for bioproduction via the reductive glycine pathway

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2023.1091899

DOI=10.3389/fbioe.2023.1091899

ISSN=2296-4185

ABSTRACT=<p>Microbial C1 fixation has a vast potential to support a sustainable circular economy. Hence, several biotechnologically important microorganisms have been recently engineered for fixing C1 substrates. However, reports about C1-based bioproduction with these organisms are scarce. Here, we describe the optimization of a previously engineered formatotrophic <italic>Escherichia coli</italic> strain. Short-term adaptive laboratory evolution enhanced biomass yield and accelerated growth of formatotrophic <italic>E. coli</italic> to 3.3 g-CDW/mol-formate and 6 h doubling time, respectively. Genome sequence analysis revealed that manipulation of acetate metabolism is the reason for better growth performance, verified by subsequent reverse engineering of the parental <italic>E. coli</italic> strain. Moreover, the improved strain is capable of growing to an OD<sub>600</sub> of 22 in bioreactor fed-batch experiments, highlighting its potential use for industrial bioprocesses. Finally, demonstrating the strain’s potential to support a sustainable, formate-based bioeconomy, lactate production from formate was engineered. The optimized strain generated 1.2 mM lactate —10% of the theoretical maximum— providing the first proof-of-concept application of the reductive glycine pathway for bioproduction.</p>