Biosynthesis of lactate-containing polyesters by metabolically engineered bacteria

Authors

  • Dr. Si Jae Park,

    Corresponding author
    1. Chemical Biotechnology Research Center, Green Chemistry Division, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
    • Chemical Biotechnology Research Center, Green Chemistry Division, Korea Research Institute of Chemical Technology, P.O. Box 107, Sinseongno 19, Yuseong-gu, Daejeon 305-600, Republic of Korea
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  • Prof. Sang Yup Lee,

    1. Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, and Institute for the BioCentury, KAIST, Daejeon, Republic of Korea
    2. Department of Bio and Brain Engineering, Department of Biological Sciences, BioProcess Engineering Research Center, and Bioinformatics Research Center, KAIST, Daejeon, Republic of Korea
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  • Tae Wan Kim,

    1. Marine Biotechnology Research Center, Korea Ocean R&D Institute, Ansan, Republic of Korea
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  • Yu Kyung Jung,

    1. Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, and Institute for the BioCentury, KAIST, Daejeon, Republic of Korea
    2. CJ CheilJedang Corporation, CJ Bldg, 500, 5-ga, Namdaemun-ro, Jung-gu, Seoul 100-749, Republic of Korea
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  • Taek Ho Yang

    1. Corporate R&D, LG Chem Research Park, Daejeon, Republic of Korea
    2. R&D Center, GS Caltex Corporation, 104-4, Munji-dong, Yuseong-gu, Daejeon 305-380, Republic of Korea
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Abstract

Due to increasing concerns about environmental problems, climate change and limited fossil resources, bio-based production of chemicals and polymers is gaining attention as one of the solutions to these problems. Polyhydroxyalkanoates (PHAs) are polyesters that can be produced by microbial fermentation. PHAs are synthesized using monomer precursors provided from 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, polytrimethylene terephthalate, and polylactic acid (PLA) are synthesized by a chemical process using monomers produced by fermentation. PLA, an attractive biomass-derived plastic, is currently synthesized by heavy metal-catalyzed ring opening polymerization of L-lactide that is made from fermentation-derived L-lactic acid. Recently, a complete biological process for the production of PLA and PLA copolymers from renewable resources has been developed by direct fermentation of recombinant bacteria employing PHA biosynthetic 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 substrate combined with systems metabolic engineering. In this article, we review recent advances in the production of lactate-containing homo- and co-polyesters. Challenges remaining to efficiently produce PLA and its copolymers and strategies to overcome these challenges through metabolic engineering combined with enzyme engineering are discussed.

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