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Anaerobic Production of Poly(3-hydroxybutyrate) and Its Precursor 3‑Hydroxybutyrate from Synthesis Gas by Autotrophic Clostridia

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journal contribution
posted on 08.05.2019, 00:00 by Sebastian Flüchter, Stéphanie Follonier, Bettina Schiel-Bengelsdorf, Frank R. Bengelsdorf, Manfred Zinn, Peter Dürre
Anaerobic production of the biopolymer poly­(3-hydroxybutyrate) (PHB) and the monomer 3-hydroxybutyrate (3-HB) was achieved using recombinant clostridial acetogens supplied with syn­(thesis) gas as the sole carbon and energy source. 3-HB production was successfully accomplished by a new synthetic pathway containing the genes thlA (encoding thiolase A), ctfA/B (encoding CoA-transferase A/B), and bdhA (encoding (R)-3-hydroxybutyrate dehydrogenase). The respective recombinant Clostridium coskatii [p83_tcb] strain produced autotrophically 0.98 ± 0.12 mM and heterotrophically 21.7 ± 0.27 mM 3-HB. As a proof of concept, production of PHB was achieved using recombinant C. coskatii and Clostridium ljungdahlii strains expressing a novel synthetic PHB pathway containing the genes thlA (encoding thiolase A), hbd (encoding 3-hydroxybutyryl-CoA dehydrogenase), crt (encoding crotonase), phaJ (encoding (R)-enoyl-CoA hydratase), and phaEC (encoding PHA synthase). The strain C. coskatii [p83_PHB_Scaceti] synthesized heterotrophically 3.4 ± 0.29% PHB per cell dry weight (CDW) and autotrophically 1.12 ± 0.12% PHB per CDW.