earticle

영어

As the concerns about environmental problems, climate change and limited fossil resources increase, bio-based production of chemicals and polymers from renewable resources gains much attention as one of the promising solutions to deal with these problems. Polyhydroxyalkanoates (PHAs) are polyesters produced and accumulated in various microorganisms. PHAs are synthesized using monomers provided from metabolite precursors of diverse metabolic pathways and are accumulated as distinct granules inside the cells. On the other hand, most so called bio-based polymers including polybutylene succinate (PBS), polytrimethylene terephthalate (PTT), and polylactic acid (PLA) are synthesized by a chemical process using fermentation-derived monomers. PLA, an attractive biomass-derived thermoplastic, is currently synthesized by ring opening polymerization (ROP) of (L)-lactide that is made from fermentation-derived (L)-lactic acid. Recently, we have developed one-step fermentative synthesis process for the production of PLA and PLA copolymers from renewable resources employing recombinant bacteria equipped with PHA biosynthesis pathways coupled with a novel metabolic pathway. This could be accomplished by establishing a pathway for generating lactyl- CoA and engineering PHA synthase to accept lactyl-CoA as a monomer combined with systems metabolic engineering. In this presentation, we report recent advances in the production of lactate-containing homo- and co- polyesters, and furthermore 2-hydroxyacid containing polyesters in recombinant microorganisms. We will discuss challenges remaining to efficiently produce 2-hydroxyacid containing polyesters such as PLA, PLA copolymers and 2-hydroxybutyrate containing PHA and development of the metabolic engineering strategies to overcome these challenges.