Abstract
Polyhydroxyalkanoates (PHA) synthesis genes phbC and orfZ cloned from Ralstonia eutropha H16 were transformed into beta-oxidation weakened Pseudomonas putida KTOY08ΔGC, a mutant of P. putida KT2442. The recombinant P. putida strain termed KTHH06 was able to produce a short-chain-length PHA block copolymer consisting of poly(3-hydroxybutyrate) (P3HB) as one block and poly(4-hydroxybutyrate) (P4HB) as another block. One-dimensional and two-dimensional nuclear magnetic resonance (NMR) clearly indicated the polymer was a diblock copolymer consisting of 20 mol % P3HB as one block and 80 mol % P4HB as another one. Differential scanning calorimetric (DSC) showed that P3HB block melting temperatures (T(m)) in the block copolymer P3HB-b-P4HB was shift to low temperature compared with homopolymer P3HB and a blend of P3HB and P4HB. The block copolymer with a number average molecular weight of 50000 Da and a polydispersity of 3.1 demonstrated a better yield and tensile strength compared with that of its related random copolymer and blend of homopolymers of P3HB and P4HB.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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4-Butyrolactone / metabolism
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Acyltransferases / chemistry
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Acyltransferases / genetics
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Acyltransferases / metabolism*
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Bacterial Proteins / chemistry
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism
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Biocompatible Materials / chemistry*
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Biocompatible Materials / pharmacology
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Biodegradation, Environmental
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Calorimetry, Differential Scanning
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Cloning, Molecular
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Cupriavidus necator / enzymology
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Cupriavidus necator / genetics*
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Genetics, Microbial / methods*
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Hydroxybutyrates / metabolism
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Molecular Weight
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Nuclear Magnetic Resonance, Biomolecular
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Plasmids
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Polyesters / metabolism
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Polyhydroxyalkanoates / analysis
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Polyhydroxyalkanoates / biosynthesis*
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Pseudomonas putida / enzymology
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Pseudomonas putida / genetics*
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Temperature
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Tensile Strength
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Tissue Engineering / methods*
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Transformation, Bacterial
Substances
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Bacterial Proteins
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Biocompatible Materials
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Hydroxybutyrates
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Polyesters
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Polyhydroxyalkanoates
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Recombinant Proteins
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poly-beta-hydroxybutyrate
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Acyltransferases
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4-Butyrolactone