%0 Journal Article
%T Synthesis of Diblock copolymer poly-3-hydroxybutyrate -block-poly-3-hydroxyhexanoate [PHB-b-PHHx] by a ¦Â-oxidation weakened Pseudomonas putida KT2442
%A Lakshmi Tripathi
%A Lin-Ping Wu
%A Jinchun Chen
%A Guo-Qiang Chen
%J Microbial Cell Factories
%D 2012
%I BioMed Central
%R 10.1186/1475-2859-11-44
%X 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 (Tg) at 2.7¡ãC and £¿16.4¡ãC, one melting temperature (Tm) at 172.1¡ãC and one cool crystallization temperature (Tc) at 69.1¡ãC 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.It is possible to produce PHA block copolymers of various kinds using the recombinant Pseudomonas putida KT2442 with its ¦Â-oxidation cycle deleted to its maximum. In comparison to a random copolymer poly-3-hydroxybutyrate-co-3-hydroxyhexanoate (P(HB-co-HHx)) and a blend sample of PHB and PHHx, the PHB-b-PHHx showed improved structural related mechanical properties.
%K Polyhydroxyalkanoates
%K PHB
%K Block copolymer
%K Pseudomonas putida
%K 3-hydroxybutyrate
%K 3-hydroxyhexanoate
%K Synthetic biology
%U http://www.microbialcellfactories.com/content/11/1/44/abstract