Special Issue "Enzymes in Monomer and Polymer Synthesis"
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A special issue of Polymers (ISSN 2073-4360).
Deadline for manuscript submissions: closed (30 December 2011)
Special Issue Editor
Guest Editor
Prof. Dr. Katja Loos
Department of Polymer Chemistry, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
Website: http://www.rug.nl/zernike/loos
E-Mail: k.u.loos@rug.nl
Phone: +31-50-3636867
Fax: +31-84-2236001
Interests: biocatalysis in polymer chemistry; enzymatic polymerizations; green polymer chemistry; biocatalytic monomer synthesis; biocatalytic polymer modification; enzyme immobilization; unraveling the mechanism of biocatalytic polymerizations; biobased monomers and polymers; sustainability; polysaccharides; starch; anionic polymerization; block copolymer synthesis
Special Issue Information
Dear Colleagues,
Enzymatic monomer synthesis, polymer modifications and polymerizations are powerful and versatile approaches which can compete with chemical and physical techniques for the production of known materials such as “commodity plastics” but also for the synthesis of novel macromolecules so far not accessible via traditional chemical approaches. Biocatalytic synthetic pathways towards polymeric materials are very attractive as they have many advantages such as mild reaction conditions, high enantio-, regio-, chemoselectivity and are nontoxic natural catalysts.
This special issue of Polymers entitled "Enzymes in Monomer and Polymer Synthesis" will cover the whole line of current research involved in this field starting from enzyme development, enzyme immobilization, sustainable monomers, in vitro and in vivo monomer synthesis towards enzymatic polymer modifications and polymerizations.
Prof. Dr. Katja Loos
Guest Editor
Submission
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed Open Access quarterly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 500 CHF (Swiss Francs).
English correction and/or formatting fees of 250 CHF (Swiss Francs) will be charged in certain cases for those articles accepted for publication that require extensive additional formatting and/or English corrections.
Keywords
- Enzymatic Polymerization
- Biocatalytic Monomer Synthesis
- Enzyme Immobilization
- Enzymatic Polymer Modification
- Polymerizations in Whole Cells
Published Papers (10 papers)
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Received: 2 December 2011; in revised form: 30 December 2011 / Accepted: 7 January 2012 / Published: 9 January 2012
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Abstract: This paper reviews preparation and applications of amylose supramolecules by means of phosphorylase-catalyzed enzymatic polymerization. When the enzymatic polymerization of α-d-glucose 1-phosphate (G-1-P) as a monomer was carried out in the presence of poly(tetrahydrofuran) (PTHF) of a hydrophobic polyether as a guest polymer, the supramolecule, i.e., an amylose-PTHF inclusion complex, was formed in the process of polymerization. Because the representation of propagation in the polymerization is similar to the way that vines of plants grow twining around rods, this polymerization method for the preparation of amylose-polymer inclusion complexes was proposed to be named “vine-twining polymerization”. Various hydrophobic polyethers, polyesters, poly(ester-ether), and polycarbonates were also employed as the guest polymer in the vine-twining polymerization to produce the corresponding inclusion complexes. To obtain the inclusion complex from a strongly hydrophobic guest polymer, the parallel enzymatic polymerization system was developed as an advanced extension of the vine-twining polymerization. In addition, it was found that amylose selectively includes one side of the guest polymer from a mixture of two resemblant guest polymers, as well as a specific range in molecular weights of the guest PTHF. Amylose also exhibited selective inclusion behavior toward stereoisomers of poly(lactide)s. Moreover, the preparation of hydrogels through the formation of inclusion complexes of amylose in vine-twining polymerization was achieved.
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Received: 9 January 2012; in revised form: 24 January 2012 / Accepted: 30 January 2012 / Published: 10 February 2012
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Abstract: Methyl epoxyricinoleate was prepared in high yield by the lipase-catalyzed epoxidation of methyl ricinoleate with H2O2. A high molecular weight polyepoxyricinoleate (PER) with a maximum weight average molecular weight (Mw) of 272,000 was enzymatically prepared by the polycondensation of methyl epoxyricinoleate using immobilized lipase from Burkholderia cepacia (lipase PS-IM) in bulk at 80 °C for 5 d. PER showed good low temperature fluidability. PER was readily cured by maleic anhydride (MA) at 80 °C to produce a chloroform-insoluble PER-MA film. Both the glass transition temperature and Young’s modulus increased with increasing MA content and PER Mw. In contrast, the elongation at break decreased with increasing MA content and PER Mw. Methyl epoxyricinoleate, PER and PER-MA showed biodegradability by activated sludge, and that of the PER-MA film decreased with increasing MA content.
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Received: 31 December 2011; in revised form: 7 February 2012 / Accepted: 8 February 2012 / Published: 21 February 2012
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Abstract: A new esterase from Thermobifida halotolerans (Thh_Est) was cloned and expressed in E. coli and investigated for surface hydrolysis of polylactic acid (PLA) and polyethylene terephthalate (PET). Thh_Est is a member of the serine hydrolases superfamily containing the -GxSxG- motif with 85–87% homology to an esterase from T. alba, to an acetylxylan esterase from T. fusca and to various Thermobifida cutinases. Thh_Est hydrolyzed the PET model substrate bis(benzoyloxyethyl)terephthalate and PET releasing terephthalic acid and mono-(2-hydroxyethyl) terephthalate in comparable amounts (19.8 and 21.5 mmol/mol of enzyme) while no higher oligomers like bis-(2-hydroxyethyl) terephthalate were detected. Similarly, PLA was hydrolyzed as indicated by the release of lactic acid. Enzymatic surface hydrolysis of PET and PLA led to a strong hydrophilicity increase, as quantified with a WCA decrease from 90.8° and 75.5° to 50.4° and to a complete spread of the water drop on the surface, respectively.
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Received: 2 January 2012; in revised form: 31 January 2012 / Accepted: 8 February 2012 / Published: 27 February 2012
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Abstract: Potato phosphorylase is able to synthesize linear polyglucans from maltoheptaose primers. By coupling maltoheptaose to butane diamine, tris(2-aminoethyl)amine and amine functionalized amine functionalized poly ethyleneglycol (PEG), new primer molecules became available. The resulting di-, tri- and macro-primers were incubated with potato phosphorylase and glycogen branching enzyme from Deinococcus geothermalis. Due to the action of both enzymes, hyperbranched polyglucan arms were grown from the maltoheptaose derivatives with a maximum degree of branching of 11%. The size of the synthesized hyperbranched polyglucans could be controlled by the ratio monomer over primer. About 60%–80% of the monomers were incorporated in the glycoconjugates. The resulting hyperbranched glycoconjugates were subjected to Dynamic Light Scattering (DLS) measurements in order to determine the hydrodynamic radius and it became obvious that the structures formed agglomerates in the range of 14–32 nm.
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Received: 3 January 2012; in revised form: 6 February 2012 / Accepted: 8 February 2012 / Published: 29 February 2012
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Abstract: Four hydrophobic amino acids (Leu, Tyr, Phe, Trp) were oligomerized by the protease papain in homo-oligomerization, binary co-oligomerization and ternary co-oligomerization. After 24 h, solid polydisperse reaction products of the homo-oligomerization were obtained in yields ranging from 30–80% by weight. A DPavg was calculated based on MALDI-ToF MS results using the ion counts for the chains in the product. Based on the DPavg and the yield of the homo-oligomerization it was determined that the amino acids can be ranked according to reactivity in the order: Tyr > Leu > Phe > Trp. Thermal degradation of the homo-oligomers shows two degradation steps: at 178–239 °C and at 300–330 °C. All the products left a significant amount of char ranging from 18–57% by weight at 800 °C. Binary co-oligomers were obtained as a polydisperse precipitate with a compositional distribution of the chains. Both the compositional and chain length distribution are calculated from MALDI-ToF mass spectra. By comparing the amount of each amino acid present in the chains it was determined that the amino acids are incorporated with a preference: Leu > Tyr > Phe > Trp. Ternary co-oligomers were also obtained as a precipitate and analyzed by MALDI-ToF MS. The compositional distribution and the chain length distribution were calculated from the MALDI-ToF data. The quantity of every amino acid in the chains was determined. Also determined was the influence on the DPavg when the oligomers were compared with corresponding binary co-oligomers. From the combined results it was concluded that in the co-oligomerization of three amino acids the reactivity preference is Leu > Tyr > Phe > Trp. Thermal degradation of all the co-oligomers showed a weight loss of 2 wt% before the main oligomer degradation step at 300–325 °C.
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Received: 30 January 2012; in revised form: 27 February 2012 / Accepted: 28 February 2012 / Published: 6 March 2012
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Abstract: Biocatalysis is propagating into practically every area of organic chemistry, amongst them radical polymerizations. A review of the recent developments of this dynamic and quickly evolving area of research is presented together with a critical evaluation of its potential to yield novel polymers and/or environmentally more benign synthetic procedures.
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Received: 8 February 2012; in revised form: 24 March 2012 / Accepted: 5 April 2012 / Published: 17 April 2012
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Abstract: Lipases were employed under solvent-free conditions to conjugate oligo-ricinoleic acid derivatives with 10-undecenoic acid, to incorporate a reactive terminal double bond into the resultant product. First, undecenoic acid was covalently attached to oligo-ricinoleic acid using immobilized Candida antarctica lipase (CAL) at a 30% yield. Thirty percent conversion also occurred for CAL-catalyzed esterification between undecenoic acid and biocatalytically-prepared polyglycerol polyricinoleate (PGPR), with attachment of undecenoic acid occurring primarily at free hydroxyls of the polyglycerol moiety. The synthesis of oligo-ricinoleyl-, undecenoyl- structured triacylglycerols comprised two steps. The first step, the 1,3-selective lipase-catalyzed interesterification of castor oil with undecenoic acid, occurred successfully. The second step, the CAL-catalyzed reaction between ricinoleyl-, undecenoyl structured TAG and ricinoleic acid, yielded approximately 10% of the desired structured triacylglycerols (TAG); however, a significant portion of the ricinoleic acid underwent self-polymerization as a side-reaction. The employment of gel permeation chromatography, normal phase HPLC, NMR, and acid value measurements was effective for characterizing the reaction pathways and products that formed.
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Received: 12 March 2012; in revised form: 8 May 2012 / Accepted: 9 May 2012 / Published: 23 May 2012
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Abstract: Biominerals such as bones, teeth and seashells, very often have advanced material properties and are a source of inspiration for material chemists. As in biological systems acidic proteins play an important role in regulating the formation of CaCO3 biominerals, we employ poly(amino acid)s to mimic the processes involved in the laboratory. Here we report on the synthesis of random aminoacid copolymers of glutamic acid (Glu), lysine (Lys) and alanine (Ala) using the ring opening polymerization (ROP) of their respective N-carboxy anhydrides (NCA). The synthetic approach yields a series of polymers with different monomer composition but with similar degrees of polymerization (DP 45–56) and comparable polydispersities (PDI 1.2–1.6). Using random copolymers we can investigate the influence of composition on the activity of the polymers without having to take into account the effects of secondary structure or specific sequences. We show that variation of the Glu content of the polymer chains affects the nucleation and thereby also the particle size. Moreover, it is shown that the polymers with the highest Glu content affect the kinetics of mineral formation such that the first precipitate is more soluble than in the case of the control.
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Received: 24 April 2012; in revised form: 12 June 2012 / Accepted: 14 June 2012 / Published: 21 June 2012
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Abstract: Polysaccharides are used extensively in various industrial applications, such as food, adhesives, coatings, construction, paper, pharmaceuticals, and personal care. Many polysaccharide structures need to be modified in order to improve their end-use properties; this is mostly done through chemical reactions. In the past 20 years many enzyme-catalyzed modifications have been developed to supplement chemical derivatization methods. Typical reactions include enzymatic oxidation, ester formation, amidation, glycosylation, and molecular weight reduction. These reactions are reviewed in this paper, with emphasis placed on the work done by the authors. The polymers covered in this review include cellulosic derivatives, starch, guar, pectin, and poly(ethylene glycol).
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Received: 9 May 2012; in revised form: 6 July 2012 / Accepted: 10 July 2012 / Published: 24 July 2012
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Abstract: We report a systematic study of a modular approach to create multi-component supramolecular nanostructures that can be tailored to be both enzyme and temperature responsive. Using a straightforward synthetic approach we functionalised a thermal responsive polymer, poly(2-isopropyl-2-oxazoline), with fluorenylmethoxycarbonyl-amino acids that drive the self-assembly. Depending on the properties of appended amino acids, these polymers undergo substantial morphological changes in response to the catalytic action of alkaline phosphatase.
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Last update: 20 June 2011
