Co-expression of polyhydroxyalkanoate synthase and (R)-enoyl-CoA hydratase genes of Aeromonas caviae establishes copolyester biosynthesis pathway in Escherichia coli

Authors

  • Toshiaki Fukui,

    1. Polymer Chemistry Laboratory and the RIKEN Group of the Research Institute of Innovative Technology for the Earth (RITE), The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan
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  • Satoru Yokomizo,

    1. Polymer Chemistry Laboratory and the RIKEN Group of the Research Institute of Innovative Technology for the Earth (RITE), The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan
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  • Genta Kobayashi,

    1. Polymer Chemistry Laboratory and the RIKEN Group of the Research Institute of Innovative Technology for the Earth (RITE), The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan
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  • Yoshiharu Doi

    Corresponding author
    1. Polymer Chemistry Laboratory and the RIKEN Group of the Research Institute of Innovative Technology for the Earth (RITE), The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan
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*Corresponding author. Tel: +81 (48) 467-9402; Fax: +81 (48) 462-4667; E-mail: ydoi@postman.riken.go.jp

Abstract

Polyhydroxyalkanoate biosynthesis genes of Aeromonas caviae were expressed in Escherichia coli LS5218 (fadR atoC(Con)), and the polyhydroxyalkanoate-producing ability of the recombinants was investigated. A LS5218 strain harboring only phaCAc (polyhydroxyalkanoate synthase gene) did not accumulate any polyhydroxyalkanoate from dodecanoate in spite of the existence of translated polyhydroxyalkanoate synthase protein, whereas co-expression phaCAc and phaJAc ((R)-specific enoyl-CoA hydratase gene) resulted in the accumulation of P(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer up to 7–11 wt% of dry cell weight from octanoate and dodecanoate. These results indicated that both phaCAc and phaJAc are essential for E. coli LS5218 to establish the polyhydroxyalkanoate biosynthesis pathway from alkanoic acids. The copolyester content in the strain expressing both the genes under the lac promoter control reached to 38 wt% from dodecanoate. Enzyme assays suggest that efficient monomer formation via β-oxidation by a high level expression of phaJAc was important to achieve a high polyhydroxyalkanoate content in the recombinant E. coli.

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