scholarly journals Biosynthesis of glycolate-based polyesters containing medium-chain-length 3-hydroxyalkanoates in recombinant Escherichia coli expressing engineered polyhydroxyalkanoate synthase

2011 ◽  
Vol 156 (3) ◽  
pp. 214-217 ◽  
Author(s):  
Ken’ichiro Matsumoto ◽  
Ayako Ishiyama ◽  
Kohei Sakai ◽  
Tetsufumi Shiba ◽  
Seiichi Taguchi
2019 ◽  
Vol 128 (2) ◽  
pp. 191-197 ◽  
Author(s):  
Saki Goto ◽  
Ayaka Hokamura ◽  
Hideki Shiratsuchi ◽  
Seiichi Taguchi ◽  
Ken'ichiro Matsumoto ◽  
...  

Author(s):  
Hiroya Tomita ◽  
Keigo Satoh ◽  
Christopher T Nomura ◽  
Ken'ichiro Matsumoto

Abstract Chimeric polyhydroxyalkanoate synthase PhaCAR is characterized by the capacity to incorporate unusual glycolate (GL) units and spontaneously synthesize block copolymers. The GL and 3-hydroxybutyrate (3HB) copolymer synthesized by PhaCAR is a random-homo block copolymer, poly(GL-ran-3HB)-b-poly(3HB). In the present study, medium-chain-length 3-hydroxyhexanoate (3HHx) units were incorporated into this copolymer using PhaCAR for the first time. The coenzyme A (CoA) ligase from Pseudomonas oleovorans (AlkK) serves as a simple 3HHx-CoA supplying route in Escherichia coli from exogenously supplemented 3HHx. NMR analyses of the obtained polymers revealed that 3HHx units were randomly connected to 3HB units, whereas GL units were heterogeneously distributed. Therefore, the polymer is composed of two segments: P(3HB-co-3HHx) and P(GL-co-3HB-co-3HHx). The thermal and mechanical properties of the terpolymer indicate no contiguous P(3HB) segments in the material, consistent with the NMR results. Therefore, PhaCAR synthesized the novel block copolymer P(3HB-co-3HHx)-b-P(GL-co-3HB-co-3HHx), which is the first block PHA copolymer comprising two copolymer segments.


2003 ◽  
Vol 185 (18) ◽  
pp. 5391-5397 ◽  
Author(s):  
Si Jae Park ◽  
Sang Yup Lee

ABSTRACT The biosynthetic pathway of medium-chain-length (MCL) polyhydroxyalkanoates (PHAs) from fatty acids has been established in fadB mutant Escherichia coli strain by expressing the MCL-PHA synthase gene. However, the enzymes that are responsible for the generation of (R)-3-hydroxyacyl coenzyme A (R3HA-CoAs), the substrates for PHA synthase, have not been thoroughly elucidated. Escherichia coli MaoC, which is homologous to Pseudomonas aeruginosa (R)-specific enoyl-CoA hydratase (PhaJ1), was identified and found to be important for PHA biosynthesis in a fadB mutant E. coli strain. When the MCL-PHA synthase gene was introduced, the fadB maoC double-mutant E. coli WB108, which is a derivative of E. coli W3110, accumulated 43% less amount of MCL-PHA from fatty acid compared with the fadB mutant E. coli WB101. The PHA biosynthetic capacity could be restored by plasmid-based expression of the maoCEc gene in E. coli WB108. Also, E. coli W3110 possessing fully functional β-oxidation pathway could produce MCL-PHA from fatty acid by the coexpression of the maoCEc gene and the MCL-PHA synthase gene. For the enzymatic analysis, MaoC fused with His6-Tag at its C-terminal was expressed in E. coli and purified. Enzymatic analysis of tagged MaoC showed that MaoC has enoyl-CoA hydratase activity toward crotonyl-CoA. These results suggest that MaoC is a new enoyl-CoA hydratase involved in supplying (R)-3-hydroxyacyl-CoA from the β-oxidation pathway to PHA biosynthetic pathway in the fadB mutant E. coli strain.


2017 ◽  
Vol 239 ◽  
pp. 542-545 ◽  
Author(s):  
Meng Wang ◽  
Kaili Nie ◽  
Hao Cao ◽  
Haijun Xu ◽  
Yunming Fang ◽  
...  

2011 ◽  
Vol 78 (2) ◽  
pp. 519-527 ◽  
Author(s):  
Qin Wang ◽  
Ryan C. Tappel ◽  
Chengjun Zhu ◽  
Christopher T. Nomura

ABSTRACTPseudomonas putidaKT2440 is capable of producing medium-chain-length polyhydroxyalkanoates (MCL-PHAs) when grown on unrelated carbon sources during nutrient limitation. Transcription levels of genes putatively involved in PHA biosynthesis were assessed by quantitative real-time PCR (qRT-PCR) inP. putidagrown on glycerol as a sole carbon source. The results showed that two genes,phaGand the PP0763 gene, were highly upregulated among genes potentially involved in the biosynthesis of MCL-PHAs from unrelated carbon sources. Previous studies have describedphaGas a 3-hydroxyacyl-acyl carrier protein (ACP)-coenzyme A (CoA) transferase, and based on homology, the PP0763 gene was predicted to encode a medium-chain-fatty-acid CoA ligase. High expression levels of these genes during PHA production inP. putidaled to the hypothesis that these two genes are involved in PHA biosynthesis from non-fatty acid carbon sources, such as glucose and glycerol. ThephaGppand PP0763 genes fromP. putidawere cloned and coexpressed with the engineeredPseudomonassp. 61-3 PHA synthase genephaCl(STQK)psin recombinantEscherichia coli. Up to 400 mg liter−1MCL-PHAs was successfully produced from glucose. This study has produced the largest amount of MCL-PHAs reported from non-fatty acid carbon sources in recombinantE. colito date and opens up the possibility of using inexpensive feedstocks to produce MCL-PHA polymers.


2004 ◽  
Vol 70 (2) ◽  
pp. 999-1007 ◽  
Author(s):  
Christopher T. Nomura ◽  
Kazunori Taguchi ◽  
Seiichi Taguchi ◽  
Yoshiharu Doi

ABSTRACT Polyhydroxyalkanoates (PHAs) can be divided into three main types based on the sizes of the monomers incorporated into the polymer. Short-chain-length (SCL) PHAs consist of monomer units of C3 to C5, medium-chain-length (MCL) PHAs consist of monomer units of C6 to C14, and SCL-MCL PHAs consist of monomers ranging in size from C4 to C14. Although previous studies using recombinant Escherichia coli have shown that either SCL or MCL PHA polymers could be produced from glucose, this study presents the first evidence that an SCL-MCL PHA copolymer can be made from glucose in recombinant E. coli. The 3-ketoacyl-acyl carrier protein synthase III gene (fabH) from E. coli was modified by saturation point mutagenesis at the codon encoding amino acid 87 of the FabH protein sequence, and the resulting plasmids were cotransformed with either the pAPAC plasmid, which harbors the Aeromonas caviae PHA synthase gene (phaC), or the pPPAC plasmid, which harbors the Pseudomonas sp. strain 61-3 PHA synthase gene (phaC1), and the abilities of these strains to accumulate PHA from glucose were assessed. It was found that overexpression of several of the mutant fabH genes enabled recombinant E. coli to induce the production of monomers of C4 to C10 and subsequently to produce unusual PHA copolymers containing SCL and MCL units. The results indicate that the composition of PHA copolymers may be controlled by the monomer-supplying enzyme and further reinforce the idea that fatty acid biosynthesis may be used to supply monomers for PHA production.


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