title: Chemo-enzymatic synthesis of polyhydroxyalkanoate by an improved two-phase reaction system (TPRS).
abstract: In our previous paper, we synthesized poly-3-hydroxybutyrate [P(3HB)] by using the water-organic solvent two-phase reaction system (TPRS), in which thiophenyl (R)-3-hydroxybutyrate [(R)-3HBTP] was used as a precursor of 3HBCoA. We have developed an improved TPRS for the chemo-enzymatic synthesis of polyhydroxyalkanoate (PHA). In this method, acetyl thioester of ethyl thioglycolate (AcETG) was used as a precursor of acetylCoA (AcCoA), which was a donor of CoA. The AcCoA was formed by the ester exchange reaction between CoA in the water phase and AcETG in the organic solvent phase. The AcCoA and free 3-hydroxybutyrate (3HB) in the water phase were converted into 3HBCoA and acetate by a CoA transfer reaction of propionylCoA transferase (PCT). The synthesized 3HBCoA was polymerized sequentially by PHA synthase, and P(3HB) was successfully formed. The maximal yield of P(3HB) was 1.2 g/l under the optimal reaction condition; this is comparable to that of in vivo PHA production. Furthermore, the number of enzymes was reduced and enzyme preparation was simplified by the construction of a fusion protein, PCT-PhaC. The chemo-enzymatic synthesis of P(3HB-co-3-hydroxypropionate) and P(3HB-co-3-mercaptopropionate) was also achieved by the improved TPRS using the fusion protein.
authors.affiliation: Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University, N13W8 Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Xuerong
authors.initials: X
authors.lastname: Han
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Satoh
authors.forename: Kenji
authors.initials: K
authors.lastname: Tajima
authors.forename: Tokuo
authors.initials: T
authors.lastname: Matsushima
authors.forename: Masanobu
authors.initials: M
authors.lastname: Munekata
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000378:metabolism; D000217:Acyltransferases / Q000378:metabolism; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D002152:Calorimetry, Differential Scanning; D004800:Enzymes, Immobilized / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism; D008958:Models, Molecular; D010421:Pentanoic Acids / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D015202:Protein Engineering; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D000094122:Polyhydroxybutyrates
chemical_list: D020155:3-Hydroxybutyric Acid; D000217:Acyltransferases; D001426:Bacterial Proteins; D004800:Enzymes, Immobilized; D006885:Hydroxybutyrates; D010421:Pentanoic Acids; D011091:Polyesters; D054813:Polyhydroxyalkanoates; D011994:Recombinant Proteins; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates; C077225:poly(3-hydroxyalkanoic acid) synthase