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Sugar Synthesis from CO2 in Escherichia coli

Antonovsky, Niv, Gleizer, Shmuel, Noor, Elad, Zohar, Yehudit, Herz, Elad, Barenholz, Uri, Zelcbuch, Lior, Amram, Shira, Wides, Aryeh, Tepper, Naama, Davidi, Dan, Bar-On, Yinon, Bareia, Tasneem, Wernick, David G., Shani, Ido, Malitsky, Sergey, Jona, Ghil, Bar-Even, Arren, Milo, Ron
Cell 2016 v.166 pp. 115-125
Escherichia coli, bacteria, biomass, biosynthesis, biotechnology, carbon, carbon dioxide, carbon dioxide fixation, energy, evolution, mutation, phenotype, pyruvic acid, sequence analysis, sugars, synthesis
Can a heterotrophic organism be evolved to synthesize biomass from CO2 directly? So far, non-native carbon fixation in which biomass precursors are synthesized solely from CO2 has remained an elusive grand challenge. Here, we demonstrate how a combination of rational metabolic rewiring, recombinant expression, and laboratory evolution has led to the biosynthesis of sugars and other major biomass constituents by a fully functional Calvin-Benson-Bassham (CBB) cycle in E. coli. In the evolved bacteria, carbon fixation is performed via a non-native CBB cycle, while reducing power and energy are obtained by oxidizing a supplied organic compound (e.g., pyruvate). Genome sequencing reveals that mutations in flux branchpoints, connecting the non-native CBB cycle to biosynthetic pathways, are essential for this phenotype. The successful evolution of a non-native carbon fixation pathway, though not yet resulting in net carbon gain, strikingly demonstrates the capacity for rapid trophic-mode evolution of metabolism applicable to biotechnology.[Display omitted]