Biosynthesis of poly(3-hydroxydecanoate) and 3-hydroxydodecanoate dominating polyhydroxyalkanoates by β-oxidation pathway inhibited Pseudomonas putida.
Pseudomonas putida KT2442 produces medium-chain-length polyhydroxyalkanoates consisting of 3-hydroxyhexanoate (3HHx), 3-hydroxyoctanoate (3HO), 3-hydroxydecanoate (3HD), 3-hydroxydodecanoate (3HDD) and 3-hydroxytetradecanoate (3HTD) from relevant fatty acids. P. puitda KT2442 was found to contain key fatty acid degradation enzymes encoded by genes PP2136, PP2137 (fadB and fadA) and PP2214, PP2215 (fadB2x and fadAx), respectively. In this study, the above enzymes and other important fatty acid degradation enzymes, including 3-hydroxyacyl-CoA dehydrogenase and acyl-CoA dehydrogenase encoded by genes PP2047 and PP2048, respectively, were studied for their effects on PHA structures. Mutant P. puitda KTQQ20 was constructed by knocking out the above six genes and also 3-hydroxyacyl-CoA-acyl carrier protein transferase encoded by PhaG, leading to a significant reduction of fatty acid β-oxidation activity. Therefore, P. puitda KTQQ20 synthesized homopolymer poly-3-hydroxydecanoate (PHD) or P(3HD-co-84mol% 3HDD), when grown on decanoic acid or dodecanoic acid. Melting temperatures of PHD and P(3HD-co-84mol% 3HDD) were 72 and 78 °C, respectively. Thermal and mechanical properties of PHD and P(3HD-co-84mol% 3HDD) were much better as compared with an mcl-PHA, consisting of lower content of C10 or C12 monomers. For the first time, it was shown that homopolymer PHD and 3HDD monomers dominating PHA could be synthesized by β-oxidation inhibiting P. putida grown on relevant carbon sources.
Liu
Qian
Q
Multidisciplinary Research Center, Shantou University, Shantou 515063, Guangdong, China.
Luo
Ge
G
Zhou
Xin Rong
XR
Chen
Guo-Qiang
GQ
D064429:Fatty Acid Synthases / Q000502:physiology*; D010084:Oxidation-Reduction; D011091:Polyesters / Q000378:metabolism*; D015202:Protein Engineering / Q000379:methods*; D016958:Pseudomonas putida / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013228:Stearates / Q000378:metabolism*
D011091:Polyesters; D011994:Recombinant Proteins; D013228:Stearates; C488799:poly(3-hydroxydecanoate); C024708:3-hydroxyoctadecanoate; D064429:Fatty Acid Synthases