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

Appl Microbiol Biotechnol. 2012 Mar;93(5):1917-25. doi: 10.1007/s00253-011-3718-0. Epub 2011 Nov 30.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyl Coenzyme A / metabolism
  • Corynebacterium glutamicum / genetics
  • Corynebacterium glutamicum / metabolism*
  • Lactic Acid / metabolism*
  • Metabolic Networks and Pathways / genetics
  • Polyesters
  • Polymers / metabolism*


  • Acyl Coenzyme A
  • Polyesters
  • Polymers
  • lactoyl-coenzyme A
  • 3-hydroxybutyryl-coenzyme A
  • Lactic Acid
  • poly(lactide)