Synthesis of Diblock copolymer poly-3-hydroxybutyrate -<it>block</it>-poly-3-hydroxyhexanoate [PHB-<it>b</it>-PHHx] by a <it>β</it>-oxidation weakened <it>Pseudomonas putida</it> KT2442
<p>Abstract</p> <p>Background</p> <p>Block polyhydroxyalkanoates (PHA) were reported to be resistant against polymer aging that negatively affects polymer properties. Recently, more and more attempts have been directed to make PHA block copolymers. Diblock copolymers PH...
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BMC
2012-04-01
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Series: | Microbial Cell Factories |
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Online Access: | http://www.microbialcellfactories.com/content/11/1/44 |
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author | Tripathi Lakshmi Wu Lin-Ping Chen Jinchun Chen Guo-Qiang |
author_facet | Tripathi Lakshmi Wu Lin-Ping Chen Jinchun Chen Guo-Qiang |
author_sort | Tripathi Lakshmi |
collection | DOAJ |
description | <p>Abstract</p> <p>Background</p> <p>Block polyhydroxyalkanoates (PHA) were reported to be resistant against polymer aging that negatively affects polymer properties. Recently, more and more attempts have been directed to make PHA block copolymers. Diblock copolymers PHB-<it>b</it>-PHHx consisting of poly-3-hydroxybutyrate (PHB) block covalently bonded with poly-3-hydroxyhexanoate (PHHx) block were for the first time produced successfully by a recombinant <it>Pseudomonas putida</it> KT2442 with its <it>β</it>-oxidation cycle deleted to its maximum.</p> <p>Results</p> <p>The chloroform extracted polymers were characterized by nuclear magnetic resonance (NMR), thermo- and mechanical analysis. NMR confirmed the existence of diblock copolymers consisting of 58 mol% PHB as the short chain length block with 42 mol% PHHx as the medium chain length block. The block copolymers had two glass transition temperatures (<it>T</it><sub><it>g</it></sub>) at 2.7°C and −16.4°C, one melting temperature (<it>T</it><sub><it>m</it></sub>) at 172.1°C and one cool crystallization temperature (<it>T</it><sub><it>c</it></sub>) at 69.1°C as revealed by differential scanning calorimetry (DSC), respectively. This is the first microbial short-chain-length (scl) and medium-chain-length (mcl) PHA block copolymer reported.</p> <p>Conclusions</p> <p>It is possible to produce PHA block copolymers of various kinds using the recombinant <it>Pseudomonas putida</it> KT2442 with its <it>β</it>-oxidation cycle deleted to its maximum. In comparison to a random copolymer poly-3-hydroxybutyrate-<it>co</it>-3-hydroxyhexanoate (P(HB-<it>co</it>-HHx)) and a blend sample of PHB and PHHx, the PHB-<it>b</it>-PHHx showed improved structural related mechanical properties.</p> |
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spelling | doaj.art-5288e27ec19d45199397519e26c8e2bc2022-12-22T01:48:42ZengBMCMicrobial Cell Factories1475-28592012-04-011114410.1186/1475-2859-11-44Synthesis of Diblock copolymer poly-3-hydroxybutyrate -<it>block</it>-poly-3-hydroxyhexanoate [PHB-<it>b</it>-PHHx] by a <it>β</it>-oxidation weakened <it>Pseudomonas putida</it> KT2442Tripathi LakshmiWu Lin-PingChen JinchunChen Guo-Qiang<p>Abstract</p> <p>Background</p> <p>Block polyhydroxyalkanoates (PHA) were reported to be resistant against polymer aging that negatively affects polymer properties. Recently, more and more attempts have been directed to make PHA block copolymers. Diblock copolymers PHB-<it>b</it>-PHHx consisting of poly-3-hydroxybutyrate (PHB) block covalently bonded with poly-3-hydroxyhexanoate (PHHx) block were for the first time produced successfully by a recombinant <it>Pseudomonas putida</it> KT2442 with its <it>β</it>-oxidation cycle deleted to its maximum.</p> <p>Results</p> <p>The chloroform extracted polymers were characterized by nuclear magnetic resonance (NMR), thermo- and mechanical analysis. NMR confirmed the existence of diblock copolymers consisting of 58 mol% PHB as the short chain length block with 42 mol% PHHx as the medium chain length block. The block copolymers had two glass transition temperatures (<it>T</it><sub><it>g</it></sub>) at 2.7°C and −16.4°C, one melting temperature (<it>T</it><sub><it>m</it></sub>) at 172.1°C and one cool crystallization temperature (<it>T</it><sub><it>c</it></sub>) at 69.1°C as revealed by differential scanning calorimetry (DSC), respectively. This is the first microbial short-chain-length (scl) and medium-chain-length (mcl) PHA block copolymer reported.</p> <p>Conclusions</p> <p>It is possible to produce PHA block copolymers of various kinds using the recombinant <it>Pseudomonas putida</it> KT2442 with its <it>β</it>-oxidation cycle deleted to its maximum. In comparison to a random copolymer poly-3-hydroxybutyrate-<it>co</it>-3-hydroxyhexanoate (P(HB-<it>co</it>-HHx)) and a blend sample of PHB and PHHx, the PHB-<it>b</it>-PHHx showed improved structural related mechanical properties.</p>http://www.microbialcellfactories.com/content/11/1/44PolyhydroxyalkanoatesPHBBlock copolymer<it>Pseudomonas putida</it>3-hydroxybutyrate3-hydroxyhexanoateSynthetic biology |
spellingShingle | Tripathi Lakshmi Wu Lin-Ping Chen Jinchun Chen Guo-Qiang Synthesis of Diblock copolymer poly-3-hydroxybutyrate -<it>block</it>-poly-3-hydroxyhexanoate [PHB-<it>b</it>-PHHx] by a <it>β</it>-oxidation weakened <it>Pseudomonas putida</it> KT2442 Microbial Cell Factories Polyhydroxyalkanoates PHB Block copolymer <it>Pseudomonas putida</it> 3-hydroxybutyrate 3-hydroxyhexanoate Synthetic biology |
title | Synthesis of Diblock copolymer poly-3-hydroxybutyrate -<it>block</it>-poly-3-hydroxyhexanoate [PHB-<it>b</it>-PHHx] by a <it>β</it>-oxidation weakened <it>Pseudomonas putida</it> KT2442 |
title_full | Synthesis of Diblock copolymer poly-3-hydroxybutyrate -<it>block</it>-poly-3-hydroxyhexanoate [PHB-<it>b</it>-PHHx] by a <it>β</it>-oxidation weakened <it>Pseudomonas putida</it> KT2442 |
title_fullStr | Synthesis of Diblock copolymer poly-3-hydroxybutyrate -<it>block</it>-poly-3-hydroxyhexanoate [PHB-<it>b</it>-PHHx] by a <it>β</it>-oxidation weakened <it>Pseudomonas putida</it> KT2442 |
title_full_unstemmed | Synthesis of Diblock copolymer poly-3-hydroxybutyrate -<it>block</it>-poly-3-hydroxyhexanoate [PHB-<it>b</it>-PHHx] by a <it>β</it>-oxidation weakened <it>Pseudomonas putida</it> KT2442 |
title_short | Synthesis of Diblock copolymer poly-3-hydroxybutyrate -<it>block</it>-poly-3-hydroxyhexanoate [PHB-<it>b</it>-PHHx] by a <it>β</it>-oxidation weakened <it>Pseudomonas putida</it> KT2442 |
title_sort | synthesis of diblock copolymer poly 3 hydroxybutyrate it block it poly 3 hydroxyhexanoate phb it b it phhx by a it β it oxidation weakened it pseudomonas putida it kt2442 |
topic | Polyhydroxyalkanoates PHB Block copolymer <it>Pseudomonas putida</it> 3-hydroxybutyrate 3-hydroxyhexanoate Synthetic biology |
url | http://www.microbialcellfactories.com/content/11/1/44 |
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