scholarly journals Biosynthesis of Random-Homo Block Copolymer Poly[Glycolate-ran-3-Hydroxybutyrate (3HB)]-b-Poly(3HB) Using Sequence-Regulating Chimeric Polyhydroxyalkanoate Synthase in Escherichia coli

2020 ◽  
Vol 8 ◽  
Author(s):  
Shuzo Arai ◽  
Sayaka Sakakibara ◽  
Robin Mareschal ◽  
Toshihiko Ooi ◽  
Manfred Zinn ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Block Copolymer ◽  
Random Copolymer ◽  
Pha Synthase ◽  
Molar Ratio ◽  
Scanning Calorimetry ◽  
Solvent Fractionation ◽  
Covalent Linkage ◽  
Polyhydroxyalkanoate Synthase ◽  
Copolymer Poly

Glycolate (GL)-containing polyhydroxyalkanoate (PHA) was synthesized in Escherichia coli expressing the engineered chimeric PHA synthase PhaCAR and coenzyme A transferase. The cells produced poly[GL-co-3-hydroxybutyrate (3HB)] with the supplementation of GL and 3HB, thus demonstrating that PhaCAR is the first known class I PHA synthase that is capable of incorporating GL units. The triad sequence analysis using 1H nuclear magnetic resonance indicated that the obtained polymer was composed of two distinct regions, a P(GL-ran-3HB) random segment and P(3HB) homopolymer segment. The random segment was estimated to contain a 71 mol% GL molar ratio, which was much greater than the value (15 mol%) previously achieved by using PhaC1PsSTQK. Differential scanning calorimetry analysis of the polymer films supported the presence of random copolymer and homopolymer phases. The solvent fractionation of the polymer indicated the presence of a covalent linkage between these segments. Therefore, it was concluded that PhaCAR synthesized a novel random-homo block copolymer, P(GL-ran-3HB)-b-P(3HB).

scholarly journals Artificial polyhydroxyalkanoate poly[2-hydroxybutyrate-block-3-hydroxybutyrate] elastomer-like material

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuki Kageyama ◽  
Hiroya Tomita ◽  
Takuya Isono ◽  
Toshifumi Satoh ◽  
Ken’ichiro Matsumoto
Keyword(s):  
Block Copolymer ◽  
Random Copolymer ◽  
Pha Synthase ◽  
X Ray Diffraction ◽  
Elastic Materials ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Monomer Sequence ◽  
Copolymer Poly ◽  
Slow Contraction

AbstractThe first polyhydroxyalkanoate (PHA) block copolymer poly(2-hydroxybutyrate-b-3-hydroxybutyrate) [P(2HB-b-3HB)] was previously synthesized using engineered Escherichia coli expressing a chimeric PHA synthase PhaCAR with monomer sequence-regulating capacity. In the present study, the physical properties of the block copolymer and its relevant random copolymer P(2HB-ran-3HB) were evaluated. Stress–strain tests on the P(88 mol% 2HB-b-3HB) film showed an increasing stress value during elongation up to 393%. In addition, the block copolymer film exhibited slow contraction behavior after elongation, indicating that P(2HB-b-3HB) is an elastomer-like material. In contrast, the P(92 mol% 2HB-ran-3HB) film, which was stretched up to 692% with nearly constant stress, was stretchable but not elastic. The differential scanning calorimetry and wide-angle X-ray diffraction analyses indicated that the P(2HB-b-3HB) contained the amorphous P(2HB) phase and the crystalline P(3HB) phase, whereas P(2HB-ran-3HB) was wholly amorphous. Therefore, the elasticity of P(2HB-b-3HB) can be attributed to the presence of the crystalline P(3HB) phase and a noncovalent crosslinked structure by the crystals. These results show the potential of block PHAs as elastic materials.

scholarly journals Artificial polyhydroxyalkanoate poly[2-hydroxybutyrate-block-3-hydroxybutyrate] elastomer-like material

2021 ◽  
Author(s):  
Yuki Kageyama ◽  
Hiroya Tomita ◽  
Takuya Isono ◽  
Toshifumi Satoh ◽  
Ken’ichiro Matsumoto
Keyword(s):  
Block Copolymer ◽  
Random Copolymer ◽  
Pha Synthase ◽  
X Ray Diffraction ◽  
Elastic Materials ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Monomer Sequence ◽  
Copolymer Poly ◽  
Slow Contraction

Abstract The first polyhydroxyalkanoate (PHA) block copolymer poly(2-hydroxybutyrate-b-3-hydroxybutyrate) [P(2HB-b-3HB)] was previously synthesized using engineered Escherichia coli expressing a chimeric PHA synthase PhaCAR with monomer sequence-regulating capacity. In the present study, the physical properties of the block copolymer and its relevant random copolymer P(2HB-ran-3HB) were evaluated. Stress–strain tests on the P(88 mol% 2HB-b-3HB) film showed an increasing stress value during elongation up to 393%. In addition, the block copolymer film exhibited slow contraction behavior after elongation, indicating that P(2HB-b-3HB) is an elastomer-like material. In contrast, the P(92 mol% 2HB-ran-3HB) film, which was stretched up to 692% with nearly constant stress, was stretchable but not elastic. The differential scanning calorimetry and wide-angle X-ray diffraction analyses indicated that the P(2HB-b-3HB) contained the amorphous P(2HB) phase and the crystalline P(3HB) phase, whereas P(2HB-ran-3HB) was wholly amorphous. Therefore, the elasticity of P(2HB-b-3HB) can be attributed to the presence of the crystalline P(3HB) phase. These results show the potential of block PHAs as elastic materials.

scholarly journals Biosynthesis of poly(glycolate-co-3-hydroxybutyrate-co-3-hydroxyhexanoate) in Escherichia coli expressing sequence-regulating polyhydroxyalkanoate synthase and medium-chain-length 3-hydroxyalkanoic acid coenzyme A ligase

2021 ◽  
Author(s):  
Hiroya Tomita ◽  
Keigo Satoh ◽  
Christopher T Nomura ◽  
Ken'ichiro Matsumoto
Keyword(s):  
Escherichia Coli ◽  
Block Copolymer ◽  
Chain Length ◽  
Coenzyme A ◽  
Medium Chain ◽  
Medium Chain Length ◽  
Coa Ligase ◽  
Coenzyme A Ligase ◽  
Polyhydroxyalkanoate Synthase ◽  
Copolymer Poly

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.

scholarly journals Characterization of the Highly Active Polyhydroxyalkanoate Synthase of Chromobacterium sp. Strain USM2

2011 ◽  
Vol 77 (9) ◽  
pp. 2926-2933 ◽  
Author(s):  
Kesaven Bhubalan ◽  
Jo-Ann Chuah ◽  
Fumi Shozui ◽  
Christopher J. Brigham ◽  
Seiichi Taguchi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Specific Activity ◽  
Weight Percent ◽  
Pha Synthase ◽  
Content Type ◽  
Highly Active ◽  
Key Enzyme ◽  
Polyhydroxyalkanoate Synthase

ABSTRACTThe synthesis of bacterial polyhydroxyalkanoates (PHA) is very much dependent on the expression and activity of a key enzyme, PHA synthase (PhaC). Many efforts are being pursued to enhance the activity and broaden the substrate specificity of PhaC. Here, we report the identification of a highly active wild-type PhaC belonging to the recently isolatedChromobacteriumsp. USM2 (PhaCCs). PhaCCsshowed the ability to utilize 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) monomers in PHA biosynthesis. Anin vitroassay of recombinant PhaCCsexpressed inEscherichia colishowed that its polymerization of 3-hydroxybutyryl-coenzyme A activity was nearly 8-fold higher (2,462 ± 80 U/g) than that of the synthase from the model strainC. necator(307 ± 24 U/g). Specific activity using a Strep2-tagged, purified PhaCCswas 238 ± 98 U/mg, almost 5-fold higher than findings of previous studies using purified PhaC fromC. necator. Efficient poly(3-hydroxybutyrate) [P(3HB)] accumulation inEscherichia coliexpressing PhaCCsof up to 76 ± 2 weight percent was observed within 24 h of cultivation. To date, this is the highest activity reported for a purified PHA synthase. PhaCCsis a naturally occurring, highly active PHA synthase with superior polymerizing ability.

The Swelling and Transition Behavior of Thermo-Responsive Poly(2-(2-Methoxyethoxy) Ethoxyethyl Methacrylate-co-Poly(Ethylene Glycol) Methyl Ether Methacrylate) Thin Films

2021 ◽  
Vol 873 ◽  
pp. 59-64
Author(s):  
Yang Yi Chen ◽  
Wen Jing Wen ◽  
Zhi Qin Su ◽  
Qi Huan ◽  
Chu Yang Zhang
Keyword(s):  
Thin Films ◽  
Ethylene Glycol ◽  
Methyl Ether ◽  
Random Copolymer ◽  
Molar Ratio ◽  
Poly Ethylene Glycol ◽  
H Nmr ◽  
Poly Ethylene ◽  
Copolymer Poly ◽  
Glycol Methyl Ether

Thermo-responsive random copolymer poly (2-(2-methoxyethoxy) ethoxyethyl methacrylate-co-poly (ethylene glycol) methyl ether methacrylate), abbreviated as P(MEO2MA-co-OEGMA300) was synthesized by 2-(2-methoxyethoxy) ethoxyethyl methacrylate (MEO2MA) and poly (ethylene glycol) methyl ether methacrylate (OEGMA300) with a molar ratio of 1:1 via atom transfer radical polymerization (ATRP). The structure of P(MEO2MA-co-OEGMA300) was confirmed by 1H NMR and GPC. The transition behaviors of P(MEO2MA-co-OEGMA300) in aqueous solution were investigated by UV-Vis and DLS. While the transition behaviors of P(MEO2MA-co-OEGMA300) thin films were probed by white light interferometry. Compared to the P(MEO2MA-co-OEGMA300) in solution, it shows a much broader transition region, which is a promising candidate for the slow release of drug in the field of medicine.

Structure mediation and ductility enhancement of poly(l-lactide) by random copolymer poly(d-lactide-co-ε-caprolactone)

2018 ◽  
Vol 38 (9) ◽  
pp. 819-826 ◽  
Author(s):  
Xiuqin Zhang ◽  
Yongai Yin ◽  
Yan Song ◽  
Xiaolu Li ◽  
Zhenfeng Dong ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Random Copolymer ◽  
Gravimetric Analysis ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
X Ray ◽  
Structure And Property ◽  
Copolymer Poly

Abstract Two types of random copolymer poly(d-lactide-co-ε-caprolactone) (PDLA-r-PCL) were added into poly(l-lactide) (PLLA) matrix by melt blending. The structure and property of PLLA/PDLA-r-PCL blends were investigated by thermal gravimetric analysis, differential scanning calorimetry, scanning electron microscopy, wide-angle X-ray diffraction, and mechanical measurement. The results suggested that PDLA-r-PCL had little effect on the thermal property of PLLA. PDLA-r-PCL uniformly dispersed in PLLA matrix, which contributed to the improvement of stretching properties. During stretching at 25°C, with the increased content of PDLA-r-PCL, the elongation at break of PLLA increased and the strength decreased. The degree of decrease in fracture strength was related to the molecular structure of PDLA-r-PCL. When a small amount of stereocomplex crystals (SC) were formed in PLLA/PDLA-r-PCL blends, the strength was maintained or slightly enhanced even though the elongation at break of the blends was significantly improved by soft chains of PCL. It might be caused by the synergistic effects of SC crystals and plasticization of PCL chains.

Effect of chain microstructure on self-assembly and emulsification of amphiphilic poly(acrylic acid)-polystyrene copolymers

2016 ◽  
Vol 18 (37) ◽  
pp. 26236-26244 ◽  
Author(s):  
Ye Zhu ◽  
Chenglin Yi ◽  
Qiong Hu ◽  
Wei Wei ◽  
Xiaoya Liu
Keyword(s):  
Chemical Composition ◽  
Block Copolymer ◽  
Acrylic Acid ◽  
Self Assembly ◽  
Random Copolymer ◽  
Similar Chemical Composition ◽  
Similar Chemical ◽  
Copolymer Poly ◽  
Poly Acrylic Acid

In this study, a series of random copolymer poly(acrylic acid-co-styrene) (P(AA-co-St)) and block copolymer poly(acrylic acid)-b-polystyrene (PAA-b-PSt) with similar chemical composition but different chain microstructure were synthesized.

scholarly journals Quadruple Hydrogen Bond-Containing A-AB-A Triblock Copolymers: Probing the Influence of Hydrogen Bonding in the Central Block

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4705
Author(s):  
Boer Liu ◽  
Xi Chen ◽  
Glenn A. Spiering ◽  
Robert B. Moore ◽  
Timothy E. Long
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Microphase Separation ◽  
Triblock Copolymers ◽  
Random Copolymer ◽  
Thermomechanical Properties ◽  
Structure Property ◽  
Scanning Calorimetry ◽  
Central Block ◽  
Quadruple Hydrogen Bonding

This work reveals the influence of pendant hydrogen bonding strength and distribution on self-assembly and the resulting thermomechanical properties of A-AB-A triblock copolymers. Reversible addition-fragmentation chain transfer polymerization afforded a library of A-AB-A acrylic triblock copolymers, wherein the A unit contained cytosine acrylate (CyA) or post-functionalized ureido cytosine acrylate (UCyA) and the B unit consisted of n-butyl acrylate (nBA). Differential scanning calorimetry revealed two glass transition temperatures, suggesting microphase-separation in the A-AB-A triblock copolymers. Thermomechanical and morphological analysis revealed the effects of hydrogen bonding distribution and strength on the self-assembly and microphase-separated morphology. Dynamic mechanical analysis showed multiple tan delta (δ) transitions that correlated to chain relaxation and hydrogen bonding dissociation, further confirming the microphase-separated structure. In addition, UCyA triblock copolymers possessed an extended modulus plateau versus temperature compared to the CyA analogs due to the stronger association of quadruple hydrogen bonding. CyA triblock copolymers exhibited a cylindrical microphase-separated morphology according to small-angle X-ray scattering. In contrast, UCyA triblock copolymers lacked long-range ordering due to hydrogen bonding induced phase mixing. The incorporation of UCyA into the soft central block resulted in improved tensile strength, extensibility, and toughness compared to the AB random copolymer and A-B-A triblock copolymer comparisons. This study provides insight into the structure-property relationships of A-AB-A supramolecular triblock copolymers that result from tunable association strengths.

Modular polymerized ionic liquid block copolymer membranes for CO2/N2 separation

2014 ◽  
Vol 2 (21) ◽  
pp. 7967-7972 ◽  
Author(s):  
Brian J. Adzima ◽  
Surendar R. Venna ◽  
Steven S. Klara ◽  
Hongkun He ◽  
Mingjiang Zhong ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Block Copolymer ◽  
Polymerized Ionic Liquid ◽  
Copolymer Poly ◽  
Poly Ionic Liquid

A robust and orthogonal approach to access modular block-copolymer poly(ionic liquid)s.

Smart control of cotton fabric comfort by cross-linking thermo-responsive poly(2-(2-methoxyethoxy) ethoxyethyl methacrylate-co-ethylene glycol methacrylate)

2016 ◽  
Vol 87 (13) ◽  
pp. 1620-1630 ◽  
Author(s):  
Yangyi Chen ◽  
Jie An ◽  
Qi Zhong ◽  
Peter Müller-Buschbaum ◽  
Jiping Wang
Keyword(s):  
Ethylene Glycol ◽  
Cotton Fabric ◽  
Random Copolymer ◽  
Cotton Fabrics ◽  
Molar Ratio ◽  
Cross Linking ◽  
Glycol Methacrylate ◽  
Moisture Permeability ◽  
Smart Control ◽  
Fabric Comfort

The smart control of cotton fabric comfort by cross-linking thermo-responsive random copolymer is investigated. The monomers 2-(2-methoxyethoxy) ethoxyethyl methacrylate (MEO2MA) and ethylene glycol methacrylate (EGMA) with a molar ratio of 17:3 are selected to synthesize the thermo-responsive random copolymer poly(2-(2-methoxyethoxy) ethoxyethyl methacrylate- co-ethylene glycol methacrylate), abbreviated as P(MEO2MA- co-EGMA). By using citric acid as a cross-linking agent, the obtained P(MEO2MA- co-EGMA) is successfully immobilized onto cotton fabrics. Smart control is achieved from the thermo-responsive behavior of the copolymer. Cross-linked P(MEO2MA- co-EGMA) will collapse when the ambient temperature exceeds its transition temperature. Therefore, the formerly compact P(MEO2MA- co-EGMA) layer will switch to a porous structure, and the air/moisture permeability of the textiles is enhanced. As the comfort of the textiles is closely related to the air/moisture permeability, a smart control of the cotton fabric comfort can be realized. In addition, the softness of cotton fabrics with and without thermo-responsive polymers does not show a prominent change, even when the applied solution concentration is as high as 16% (wt%). On the contrary, the stiffness of the cotton fabric coated with poly( N-isopropylacrylamide) (PNIPAM) is significantly higher than the original cotton fabric, indicating that homo PNIPAM is less suitable for textiles used in daily lives. Moreover, the whiteness and mechanical properties are studied and stay unchanged after cross-linking. As a consequence, the introduction of P(MEO2MA- co-EGMA) into textiles can provide textiles with smart control of cotton comfort, and it will not influence the wearabilities of the textiles.

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