Biotechnological products and process engineering

Applied Microbiology and Biotechnology

, Volume 93, Issue 5, pp 1917-1925

Engineered Corynebacterium glutamicum as an endotoxin-free platform strain for lactate-based polyester production

  • Yuyang SongAffiliated withDivision of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University
  • , Ken’ichiro MatsumotoAffiliated withDivision of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University
  • , Miwa YamadaAffiliated withDivision of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido UniversityDepartment of Biological Chemistry and Food Science, Iwate University
  • , Aoi GohdaAffiliated withDivision of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University
  • , Christopher J. BrighamAffiliated withDepartment of Biology, Massachusetts Institute of Technology
  • , Anthony J. SinskeyAffiliated withDepartment of Biology, Massachusetts Institute of Technology
  • , Seiichi TaguchiAffiliated withDivision of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University Email author 

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Abstract

The first biosynthetic system for lactate (LA)-based polyesters was previously created in recombinant Escherichia coli (Taguchi et al. 2008). Here, we have begun efforts to upgrade the prototype polymer production system to a practical stage by using metabolically engineered Gram-positive bacterium Corynebacterium glutamicum as an endotoxin-free platform. We designed metabolic pathways in C. glutamicum to generate monomer substrates, lactyl-CoA (LA-CoA), and 3-hydroxybutyryl-CoA (3HB-CoA), for the copolymerization catalyzed by the LA-polymerizing enzyme (LPE). LA-CoA was synthesized by D-lactate dehydrogenase and propionyl-CoA transferase, while 3HB-CoA was supplied by β-ketothiolase (PhaA) and NADPH-dependent acetoacetyl-CoA reductase (PhaB). The functional expression of these enzymes led to a production of P(LA-co-3HB) with high LA fractions (96.8 mol%). The omission of PhaA and PhaB from this pathway led to a further increase in LA fraction up to 99.3 mol%. The newly engineered C. glutamicum potentially serves as a food-grade and biomedically applicable platform for the production of poly(lactic acid)-like polyester.

Keywords

Polylactide Biobased plastic PHA synthase Polyhydroxyalkanoate Polyhydroxybutyrate