Biosynthesis and characterization of 3-hydroxyalkanoate terpolyesters with adjustable properties by Aeromonas hydrophila.
Polyhydroxyalkanoates (PHA) terployesters P(3HB-co-3HV-co-3HHx) consisting of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) were produced by wild-type Aeromonas hydrophila 4AK4, its recombinant harboring PHA synthesis genes phaPCJ encoding PHA binding protein phasin, PHA synthase, and enoyl-CoA hydratase, and another its recombinant harboring phaAB encoding beta-ketothiolase and acetoacetyl-CoA reductase, respectively, when grown in lauric acid and/or valerate. The terpolyesters produced by A. hydrophila 4AK4 (phaAB) grown in velarate were found to produce copolymers P(3HB-co-3HV) containing high 3HV fractions with a maximum of 99 mol% 3HV. In terpolyesters, 3HV ranged from 9 to 32 mol% depending on the valerate concentration and strain used. A maximal terpolyester P(3HB-co-3HV-co-3HHx) content in dry cells was 71 wt%. Transmission electron microscopy study of A. hydrophila 4AK4 harboring phaPCJ revealed the full occupation of terpolyester P(3HB-co-3HV-co-HHx) in the cellular spaces. Terpolyesters with various monomer compositions showed changing thermal and mechanical properties. Those with higher 3HV fractions demonstrated an improved property over the lower HV containing ones.
Zhang
Hai-Feng
HF
Multidisciplinary Research Center, Shantou University, Shantou 515063, Guangdong, China.
Ma
Long
L
Wang
Zhi-Hui
ZH
Chen
Guo-Qiang
GQ
D020155:3-Hydroxybutyric Acid / Q000032:analysis; D000102:Acetyl-CoA C-Acyltransferase / Q000235:genetics / Q000378:metabolism; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D016980:Aeromonas hydrophila / Q000235:genetics / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000235:genetics; D002208:Caproates / Q000032:analysis; D004746:Enoyl-CoA Hydratase / Q000235:genetics / Q000378:metabolism; D007850:Lauric Acids / Q000378:metabolism; D010421:Pentanoic Acids / Q000032:analysis; D037121:Plant Lectins / Q000235:genetics / Q000378:metabolism; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis* / Q000737:chemistry; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014631:Valerates / Q000378:metabolism
D002208:Caproates; D007850:Lauric Acids; D010421:Pentanoic Acids; D037121:Plant Lectins; D011091:Polyesters; D054813:Polyhydroxyalkanoates; D011994:Recombinant Proteins; D014631:Valerates; C045051:3-hydroxyhexanoic acid; C013056:beta-hydroxyvaleric acid; C030358:lauric acid; C008825:phasin; D000429:Alcohol Oxidoreductases; C023744:acetoacetyl-CoA reductase; D000217:Acyltransferases; C077225:poly(3-hydroxyalkanoic acid) synthase; D000102:Acetyl-CoA C-Acyltransferase; D004746:Enoyl-CoA Hydratase; D020155:3-Hydroxybutyric Acid