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Updated: May 30, 2026

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions
Published on: October 10, 2016
Biosynthesis and characterization of polyhydroxyalkanoate block copolymer P3HB-b-P4HB
Die Hu1, Ah-Leum Chung, Lin-Ping Wu
1MOE Key Lab of Protein Sciences, Department of Biological Sciences and Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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.
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