title: Synthesis of Medium-Chain-Length Polyhydroxyalkanoate Homopolymers, Random Copolymers, and Block Copolymers by an Engineered Strain of Pseudomonas entomophila.
abstract: Medium-chain-length polyhydroxyalkanoates (mcl-PHAs), widely used in medical area, are commonly synthesized by Pseudomonas spp. This study tries to use β-oxidation pathways engineered P. entomophila to achieve single source of a series of mcl-monomers for microbial production of PHA homopolymers. The effort is proven successful for the first time to obtain a wide range of mcl-PHA homopolymers from engineered P. entomophila LAC23 grown on various fatty acids, respectively, ranging from poly(3-hydroxyheptanoate) to poly(3-hydroxytetradecanoate). Effects of a PHA monomer chain length on thermal and crystallization properties including the changes of Tm, Tg, and Td5%are investigated. Additionally, strain LAC23 is used to synthesize random copolymers of 3-hydroxyoctanoate (3HO) and 3-hydroxydodecanoate (3HDD) or 3-hydroxytetradecanoates, their compositions could be controlled by adjusting the ratios of two related fatty acids. Meanwhile, block copolymer P(3HO)-b-P(3HDD) is synthesized by the same strain. It is found for the first time that even- and odd number mcl-PHA homopolymers have different physical properties. When the gene of the PHA synthase in the engineered P. entomophila is replaced by phaC from Aeromonas hydrophila 4AK4, poly(3-hydroxybutyrate-co-30 mol%-3-hydroxyhexanoate) is synthesized. Therefore, P. entomophila can be used to synthesize the whole range of PHA (C7-C14) homopolymers, random- and block copolymers.
authors.affiliation: School of Life Science, Tsinghua University, Beijing, 100084, China.|Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China.|Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China.|Department of Biological Engineering, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Life Science, Tsinghua University, Beijing, 100084, China.
authors.forename: Ahleum
authors.initials: A
authors.lastname: Chung
authors.affiliation: School of Life Science, Tsinghua University, Beijing, 100084, China.|Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China.|Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China.|Center for Nano and Micro Mechanics, Tsinghua University, Beijing, 100084, China.|MOE Key Lab for Industrial Biocatalysis, Tsinghua University, Beijing, 100084, China.
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Chen
mesh_terms: D000217:Acyltransferases / Q000096:biosynthesis / Q000235:genetics; D016980:Aeromonas hydrophila / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D005818:Genetic Engineering; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis / Q000235:genetics; D011549:Pseudomonas / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D054813:Polyhydroxyalkanoates; D000217:Acyltransferases; C077225:poly(3-hydroxyalkanoic acid) synthase
keywords: PHB; Pseudomonas entomophila; copolymer; homopolymer; polyhydroxyalkanoates