Biosynthesis of polyhydroxyalkanoate homopolymers by Pseudomonas putida.
Pseudomonas putida KT2442 has been a well-studied producer of medium-chain-length (mcl) polyhydroxyalkanoate (PHA) copolymers containing C6 ~ C14 monomer units. A mutant was constructed from P. putida KT2442 by deleting its phaG gene encoding R-3-hydroxyacyl-ACP-CoA transacylase and several other β-oxidation related genes including fadB, fadA, fadB2x, and fadAx. This mutant termed P. putida KTHH03 synthesized mcl homopolymers including poly(3-hydroxyhexanoate) (PHHx) and poly(3-hydroxyheptanoate) (PHHp), together with a near homopolymer poly(3-hydroxyoctanoate-co-2 mol% 3-hydroxyhexanoate) (PHO*) in presence of hexanoate, heptanoate, and octanoate, respectively. When deleted with its mcl PHA synthase genes phaC1 and phaC2, the recombinant mutant termed P. putida KTHH08 harboring pZWJ4-31 containing PHA synthesis operon phaPCJ from Aeromonas hydrophila 4AK4 accumulated homopolymer poly(3-hydroxyvalerate) (PHV) when valerate was used as carbon source. The phaC deleted recombinant mutant termed P. putida KTHH06 harboring pBHH01 holding PHA synthase PhbC from Ralstonia eutropha produced homopolymers poly(3-hydroxybutyrate) (PHB) and poly(4-hydroxybutyrate) using γ-butyrolactone was added as precursor. All the homopolymers were physically characterized. Their weight average molecular weights ranged from 1.8 x 10⁵ to 1.6 x 10⁶, their thermal stability changed with side chain lengths. The derivatives of P. putida KT2442 have been developed into a platform for production of various PHA homopolymers.
Multidisciplinary Research Center, Shantou University, Shantou, 515063 Guangdong, China.
Hong-Hui
HH
Wang
Xin-Rong
XR
Zhou
Qian
Q
Liu
Guo-Qiang
GQ
Chen
D016980:Aeromonas hydrophila / Q000201:enzymology / Q000235:genetics; D053898:Biosynthetic Pathways / Q000235:genetics; D003001:Cloning, Molecular; D020118:Cupriavidus necator / Q000201:enzymology / Q000235:genetics; D017353:Gene Deletion; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D016958:Pseudomonas putida / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D054813:Polyhydroxyalkanoates; D011994:Recombinant Proteins