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  • 1.
    Berglund, Per
    et al.
    KTH, Superseded Departments, Biotechnology.
    Vallikivi, I.
    Fransson, Linda
    KTH, Superseded Departments, Biotechnology.
    Dannacher, H.
    Holmquist, Mats
    KTH, Superseded Departments, Biotechnology.
    Martinelle, Mats
    KTH, Superseded Departments, Biotechnology.
    Björkling, F.
    Parve, O.
    Hult, Karl
    KTH, Superseded Departments, Biotechnology.
    Switched enantiopreference of Humicola lipase for 2-phenoxyalkanoic acid ester homologs can be rationalized by different substrate binding modes1999In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 10, no 21, p. 4191-4202Article in journal (Refereed)
    Abstract [en]

    Humicola lanuginosa lipase was used for enantioselective hydrolyses of a series of homologous 2-phenoxyalkanoic acid ethyl esters. The enantioselectivity (E-value) of the enzyme changed from an (R)-enantiomer preference for the smallest substrate, 2-phenoxypropanoic acid ester, to an (S)-enantiomer preference for the homologous esters with longer acyl moieties. The E-values span the range from E=13 (R) to E=56 (S). A molecular modeling study identified two different substrate-binding modes for each enantiomer. We found that the enantiomers favored different modes. This discovery provided a model that offered a rational explanation for the observed switch in enantioselectivity. (C) 1999 Elsevier Science Ltd. All rights reserved.

  • 2.
    Brännström, Sara
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Finnveden, Maja
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Itaconate based polyesters: Selectivity and performance of esterification catalysts2018In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 103, p. 370-377Article in journal (Refereed)
    Abstract [en]

    The performance of different esterification catalysts was studied for the use in synthesis of renewable polyesters from dimethyl itaconate (DMI), dimethyl succinate (DMS) and 1,4-butanediol (BD). Itaconic acid and derivatives such as DMI are interesting monomers because of their multiple functionalities and previous work has shown great potential. However, the multiple functionalities also pose challenges to avoid side reactions such as thermally initiated, premature, radical crosslinking and/or isomerization of the 1,1-disubstituted unsaturation. Additionally, the two carboxylic acids have inherently different reactivity. One key factor to control reactions with IA is to understand the performance of different catalysts. In this study, six esterification catalysts were investigated; immobilized Candida antarctica lipase B (CalB), titanium(IV)butoxide (Ti(OBu)4), p-toluenesulfonic acid (pTSA), sulfuric acid (H2SO4), 1,8-diazabicycloundec-7-ene (DBU), and 1,5,7-triazabicyclodec-5-ene (TBD). CalB and Ti(OBu)4 were selected for further characterization with appreciable differences in catalytic activity and selectivity towards DMI. CalB was the most effective catalysts and was applied at 60 °C while Ti(OBu)4 required 160 °C for a reasonable reaction rate. CalB was selective towards DMS and the non-conjugated side of DMI, resulting in polyesters with itaconate-residues mainly located at the chain ends, while Ti(OBu)4 showed low selectivity, resulting in polyesters with more randomly incorporated itaconate units. Thermal analysis of the polyesters showed that the CalB-catalyzed polyesters were semi-crystalline, whereas the Ti(OBu)4-catalyzed polyesters were amorphous, affirming the difference in monomer sequence. The polyester resins were crosslinked by UV-initiated free radical polymerization and the material properties were evaluated and showed that the crosslinked materials had similar material properties. The films from the polyester resins catalyzed by CalB were furthermore completely free from discoloration whereas the film made from the polyester resins catalyzed with Ti(OBu)4 had a yellow color, caused by the catalyst. Thus, it has been shown that CalB can be used to attain sustainable unsaturated polyesters resins for coating applications, exhibiting equally good properties as resins obtained from traditional metal-catalysis.

  • 3.
    Brännström, Sara
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Finnveden, Maja
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Razza, Nicolo
    Politecn Torino, Dept Appl Sci & Technol, Corso Duca Abruzzi 24, I-10129 Turin, Italy..
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Sangermano, Marco
    Politecn Torino, Dept Appl Sci & Technol, Corso Duca Abruzzi 24, I-10129 Turin, Italy..
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Tailoring Thermo-Mechanical Properties of Cationically UV-Cured Systems by a Rational Design of Vinyl Ether Ester Oligomers using Enzyme Catalysis2018In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 219, no 21, article id 1800335Article in journal (Refereed)
    Abstract [en]

    There is a demand for new sustainable polymeric materials. Vinyl ethers are, in this context, attractive oligomers since they polymerize fast, are non-toxic, and can be polymerized under ambient conditions. The availability of vinyl ether oligomers is, however, currently limited due to difficulties in synthesizing them without using tedious synthesis routes. This work presents the synthesis of a series of vinyl ether ester oligomers using enzyme catalysis under solvent-free conditions and the subsequent photoinduced cationic polymerization to form polymer thermosets with T(g)s ranging from -10 to 100 degrees C. The whole process is very efficient as the synthesis takes less than 1 h with no need for purification and the crosslinking is complete within 2 min.

  • 4. Cordova, A
    et al.
    Iversen, T
    Martinelle, M
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Lipase-catalysed formation of macrocycles by ring-opening polymerisation of epsilon-caprolactone1998In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 39, no 25, p. 6519-6524Article in journal (Refereed)
    Abstract [en]

    Studies were undertaken to gain mechanistic information on lactone ring-opening polymerisation reactions using Candida antarctica lipase B (Novozym 435) as the catalyst and epsilon-caprolactone as the monomer. Polymerisations were performed in organic solvents as well as without solvent at 60 degrees C. Candida antarctica lipase B catalysed concurrently with the intermolecular ring-opening polymerisation, and also the formation of macrocycles by an intramolecular condensation reaction. Candida antarctica lipase B had the highest initial rate of consumption of epsilon-caprolactone (1.2 mu mol mg(-1) min(-1)) in the bulk polymerisation, without solvent. Under these conditions, the highest average M-w, 4701 D, of poly(epsilon-caprolactone) was obtained. There were small amounts of cyclic oligomers present. When comparing the polymerisations performed in dioxane, acetonitrile and THF after 24 h reaction time with the bulk polymerisation, the average M-w of poly(epsilon-caprolactone) [2984, 1297, 1862 D, respectively] and the initial rates of monomer conversion of the enzyme (0.1, 0.05, 0.013 mu mol mg(-1) min(-1), respectively) were lower, however, the formation of cyclic oligomers was high. In dioxane, macrocycles of up to 2623 D corresponding to 23 monomer units were formed, and in acetonitrile there were mostly cyclic oligomers present. (C) 1998 Elsevier Science Ltd. All rights reserved.

  • 5.
    Eriksson, Magnus
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Boyer, Antoine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Sinigoi, Loris
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    One-Pot Enzymatic Route to Tetraallyl Ether Functional Oligoesters: Synthesis, UV Curing, and Characterization2010In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 48, no 23, p. 5289-5297Article in journal (Refereed)
    Abstract [en]

    An enzymatic one-pot route in bulk was used to synthesize tetraallyl ether (tAE) functional oligomers based on divinyl adipate, 1,4-butanediol and trimethylolpropane diallyl ether. By using lipase B from Candida antarctica as catalyst and varying the stoichiometric ratio of monomers, it was possible to reach targeted molecular weights (from 1300 to 3300 g mol(-1)) of allyl-ether functional polyesters. The enzyme catalyzed reaction reached completion (>98% conversion based on all monomers) within 24 h at 60 degrees C, under reduced pressure (72 mbar) resulting in similar to 90% yield after filtration. The tAE-functional oligoesters were photopolymerized, without any purification other than removal of the enzyme by filtration, with thiol functional monomers (dithiol, tetrathiol) in a 1: 1 ratio thiol-ene reaction. The photo-initiator, 2,2-dimethoxy-2-phenylacetophenone, was used to improve the rate of reaction under UV light. High conversions (96-99% within detection limits) were found for all thiol-ene films as determined by FT-Raman spectroscopy. The tAE-functional oligoesters were characterized by NMR, MALDI, and SEC. The UV-cured homopolymerized films and the thiol-ene films properties were characterized utilizing DSC and DMTA.

  • 6.
    Eriksson, Magnus
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Fogelström, Linda
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Enzymatic One-Pot Route to Telechelic Polypentadecalactone Epoxide: Synthesis, UV Curing, and Characterization2009In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, no 11, p. 3108-3113Article in journal (Refereed)
    Abstract [en]

    In an enzymatic one-pot procedure immobilized lipase B from Candida antarctica was used to synthesize semicrystalline diepoxy functional macromonomers based on glycidol, pentadecalactone, and adipic acid. By changing the stoichiometry of the building blocks. macromonomers of controlled molecular weight front 1400 to 2700 g mol(-1) could be afforded. The enzyme-catalyzed reaction went to completion (conversion >= 95%) within 24 h at 60 degrees C. After removal of the enzyme, the produced macromonomers were used for photopolymerization without any purification. The macromonomers readily copolymerized cationically with a cycloaliphatic diepoxide (Cyracure UVR-6110; CA-dE) to high conversion. The cross-linked copolymers formed a durable film with a degree of crystallinity depending on the macromonomer size and amount of CA-dE used, without CA-dE the macromonomers homopolymerized only to a low degree. Combined with CA-dE conversions of 85-90% were determined by FT-Raman spectroscopy. The films became more durable once reinforced with CA-dE, increasing the cross-link density and reducing the crystallinity of the PDL segments in the films.

  • 7.
    Eriksson, Magnus G.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Trey, Stacy M.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    One-pot enzymatic polycondensation to telechelic methacrylate-functional oligoesters used for film formation2011In: POLYM CHEM, ISSN 1759-9954, Vol. 2, no 3, p. 714-719Article in journal (Refereed)
    Abstract [en]

    Based on largely renewable monomers, an enzymatic one-pot polycondensation route towards functional oligomers with targeted molecular weights and end-groups was developed. This one-pot synthesis was performed by combining Candida antarctica lipase B (CALB), 2-hydroxyethyl methacrylate (HEMA), ethylene glycol, and divinyl adipate under reduced pressure (72 mbar) at 60 degrees C. The polymerization went to completion (>95% conversion for all monomers) within 24 h and the fraction of methacrylate end-groups was >90%. Three targeted dimethacrylate functional oligomers with molecular weights of 920, 1700 and 2500 g mol(-1) (degrees of polymerization 4, 8, and 13 respectively) were synthesized. The oligomer products were characterized by NMR, MALDI-TOF MS and SEC. The dimethacrylate functional oligomers were further UV homopolymerized or combined with a tetrathiol crosslinker to demonstrate the potential to produce novel networks with tunable thermal properties dependent on chain length of the telechelic building blocks. This research is the first to demonstrate methacrylate functionalization and condensation polymerization in a one step process, which expands the growing toolbox for polymer/material chemists towards an increased throughput in available macromonomers used in material design.

  • 8.
    Eriksson, Magnus
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Enzymatic one-pot polycondensation to telechelic epoxy oligomersManuscript (preprint) (Other academic)
  • 9.
    Eriksson, Magnus
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Nilsson, Camilla
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    One-pot synthesis to functional free-standing polymer film for sensor applicationsManuscript (preprint) (Other academic)
  • 10.
    Finnveden, Maja
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Brännström, Sara
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Novel sustainable synthesis of vinyl ether ester building blocks, directly from carboxylic acids and the corresponding hydroxyl vinyl ether, and their photopolymerization2018In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, no 44, p. 24716-24723Article in journal (Refereed)
    Abstract [en]

    Increased environmental awareness has led to a demand for sustainable, bio-based materials. Consequently, the development of new benign synthesis pathways utilizing a minimum of reaction steps and available bio-based building blocks is needed. In the present study, vinyl ether alcohols and functional carboxylic acids were used to synthesize bifunctional vinyl ether esters using the immobilized enzyme Candida antarctica lipase B as a catalyst. Vinyl ethers are attractive alternatives to (meth)acrylates due to low allergenic hazards, low toxicity, and fast polymerization; however, difficult synthesis limits the monomer availability. The synthesis was performed in one-pot and the described method was successful within a broad temperature range (22-90 degrees C) and in various organic solvents as well as in the bulk. The synthesis of different vinyl ether esters reached high conversions (above 90%) after less than 1 h and products were purified by removing the enzyme by filtration using only small amounts of acetone. This approach is a straightforward route to reach monomers with multiple types of functionalities that can be used as different photo-curable thermoset resins. In this work, this was demonstrated by polymerizing the monomers with cationic and radical UV-polymerization. By changing the functional carboxylic acids, the architecture of the final polymer can be tailored, herein demonstrated by two examples. In the developed versatile method, carboxylic acids can be used directly as acyl donors, constituting a more sustainable alternative to the carboxylic acid derivatives used today.

  • 11.
    Finnveden, Maja
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology. KTH Royal Institute of Technology.
    Hendil-Forssell, Peter
    Claudino, Mauro
    Johansson, Mats
    KTH, Superseded Departments (pre-2005), Fibre and Polymer Technology.
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Lipase Catalyzed Synthesis of renewable plant oil-based polyamidesManuscript (preprint) (Other academic)
    Abstract [en]

    Enzyme catalyzed synthesis towards renewable polyamides was investigated using Candida antarctica lipase B. A fatty acid-derived AB-type functional monomer, having one amine and one methyl ester functionality was homopolymerized at 80 and 140°C. Additionally, the organobase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was used as catalyst. The results from the two catalysts were comparable. However, the amount of lipase added was 1200 times lower showing that the lipase was a more efficient catalyst for this system as compared to TBD. Moreover, the AB type monomer was copolymerized with 1,12-diaminododecan to synthesize oligoamides of two different lengths.

  • 12.
    Finnveden, Maja
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Hendil-Forssell, Peter
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Claudino, Mauro
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Lipase-Catalyzed Synthesis of Renewable Plant Oil-Based Polyamides.2019In: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, no 11, article id 1730Article in journal (Refereed)
    Abstract [en]

    Enzyme catalyzed synthesis of renewable polyamides was investigated using Candida antarctica lipase B. A fatty acid-derived AB-type functional monomer, having one amine and one methyl ester functionality, was homopolymerized at 80 and 140 °C. Additionally, the organobase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was used as a catalyst. The results from the two catalysts were comparable. However, the amount of lipase added was 1.2 × 103 times lower, showing that the lipase was a more efficient catalyst for this system as compared to TBD. Moreover, the AB-type monomer was copolymerized with 1,12-diaminododecane to synthesize oligoamides of two different lengths.

  • 13.
    Finnveden, Maja
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Nameer, Samer
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats K G
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    One-Component Thiol-Alkene Functional Oligoester Resins Utilizing Lipase Catalysis2016In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935Article in journal (Refereed)
    Abstract [en]

    Chemo-enzymatic methods are powerful tools for the synthesis of novel materials. By combining the flexibility of chemical synthesis and the high selectivity of enzymes, a variety of functional materials can be achieved. In the present study, a series of α,ω-thiol telechelic oligoesters with varying amount of internal alkenes are prepared using selective lipase catalysis and are subsequently cross-linked by thiol-ene chemistry yielding alkene functional networks. Due to the reactivity of thiols and alkenes almost all present thiol-ene systems consist of two components. This work demonstrates that selective lipase catalysis in combination with renewable monomers with internal alkenes is a promising system for achieving one-component thiol-alkene functional resins with good storage stability and a high degree of thiol end-groups. The developed chemo-enzymatic route yields polymer networks with tailored amount of alkene functionalities in the final thermoset, which facilitate further postmodification.

  • 14.
    Finnveden, Maja
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Semlitsch, Stefan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    He, Oscar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Mono-substitution of symmetric diesters: selectivity of Mycobacterium smegmatis acyltransferase variants2019In: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761Article in journal (Refereed)
    Abstract [en]

    A method for selectively reacting one, out of two identical carboxylic esters in a symmetric diester has been developed. An esterase from Mycobacterium smegmatis (MsAcT) has a restricted active site resulting in a narrow acyl donor specificity. This constraint was used to develop a selective synthesis route from divinyl adipate (a symmetric diester) towards mixed vinyl adipate esters. To find a suitable catalyst, the wild type (wt) MsAcT and two MsAcT variants: a single point mutant (L12A) and a double point mutant (T93A/F154A), were immobilized and studied under solvent-free conditions. Out of the tested catalysts, MsAcT L12A was the most selective for mono-transesterification of divinyl adipate. When divinyl adipate was reacted with 1.5 equivalents of a hydroxyl vinyl ether full conversion of DVA was observed yielding over 95% mixed diester. Furthermore, the limitations for longer dicarboxylic esters were studied, showing that MsAcT T93A/F154A tolerated up to at least dimethyl sebacate.

  • 15. Gustavsson, M.
    et al.
    Lehtio, J.
    Denman, S.
    Teeri, Tuula T.
    KTH, Superseded Departments, Biotechnology.
    Hult, Karl
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    Martinelle, Mats
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    Stable linker peptides for a cellulose-binding domain-lipase fusion protein expressed in Pichia pastoris2001In: Protein Engineering, ISSN 0269-2139, E-ISSN 1460-213X, Vol. 14, no 9, p. 711-715Article in journal (Refereed)
    Abstract [en]

    Fusion proteins composed of a cellulose-binding domain from Neocallimastix patriciarum cellulase A and Candida antarctica lipase B were constructed using different linker peptides. The aim was to create proteolytically stable linkers that were able to join the functional modules without disrupting their function. Six fusion variants containing linkers of 4-44 residues were expressed in Pichia pastoris and analysed. Three variants were found to be stable throughout 7-day cultivations. The cellulose-binding capacities of fusion proteins containing short linkers were slightly lower compared with those containing long linkers. The lipase-specific activities of all variants, in solution or immobilized on to cellulose, were equal to that of the wildtype lipase.

  • 16. Gustavsson, M. T.
    et al.
    Persson, P. V.
    Iversen, T.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Teeri, Tuula T.
    KTH, School of Biotechnology (BIO), Glycoscience.
    Brumer, Harry
    KTH, School of Biotechnology (BIO), Glycoscience.
    Modification of cellulose fiber surfaces by use of a lipase and a xyloglucan endotransglycosylase2005In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 6, no 1, p. 196-203Article in journal (Refereed)
    Abstract [en]

    A strategy for the modification of cellulose fiber surfaces was developed that used the ability of Candida antarctica lipase B (CALB) to acylate carbohydrates with high regioselectivity, combined with the transglycosylating activity of the Populus tremula x P. tremuloides xyloglucan endotransglycosylase 16A (PttXET16A). Xyloglucan oligosaccharides (XGOs) prepared from tamarind xyloglucan were acylated with CALB as a catalyst and vinyl stearate or gamma-thiobutyrolactone as acyl donors to produce carbohydrate molecules with hydrophobic alkyl chains or reactive sulfhydryl groups, respectively. The modified XGOs were shown to act as glycosyl acceptors in the transglycosylation reaction catalyzed by PttXET16A and could therefore be incorporated into high M-r xyloglucan chains. The resulting xyloglucan molecules exhibited a high affinity for cellulose surfaces, which enabled the essentially irreversible introduction of fatty acid esters or thiol groups to cellulose fibers.

  • 17.
    Gustavsson, Malin T.
    et al.
    KTH, Superseded Departments, Biotechnology.
    Persson, P. V.
    Iversen, T.
    Hult, Karl
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    Martinelle, Mats
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    Polyester coating of cellulose fiber surfaces catalyzed by a cellulose-binding module-Candida antarctica lipase B fusion protein2004In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 5, no 1, p. 106-112Article in journal (Refereed)
    Abstract [en]

    A new approach to introduce polymers to cellulosic materials was developed by using the ability of a cellulose-binding module-Candida antarctica lipase B conjugate to catalyze ring-opening polymerization of epsilon-caprolactone in close proximity to cellulose fiber surfaces. The epsilon-caprolactone was introduced to the cellulose surfaces either by simple addition of liquid monomer or through gas phase. The effects of water activity and temperature on the lipase-catalyzed polymerization process were investigated. Analysis showed that the water content in the system primarily regulated the obtained polymer molecular weight, whereas the temperature influenced the reaction rate. The hydrophobicity of the obtained surfaces did not arise from covalent attachment of the poly(epsilon-caprolactone) to the surface hydroxyl groups but rather from surface-deposited polymers which could be readily extracted. The degree of lipase-catalyzed hydrolysis through introduction of water to the polymer-coated cellulose fiber surfaces was also investigated and shown to be significant.

  • 18.
    Hedfors, Cecilia
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Hendil-Forssell, Peter
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Syrén, Per-Olof
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Takwa, Mohamad
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Selectivity towards itaconic acid esters by Candida antarctica lipase B and variantsManuscript (preprint) (Other academic)
  • 19.
    Hedfors, Cecilia
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Lipase chemoselectivity towards alcohol and thiol acyl acceptors in a transacylation reaction2010In: Journal of Molecular Catalysis B: Enzymatic, ISSN 1381-1177, E-ISSN 1873-3158, Vol. 66, no 1-2, p. 120-123Article in journal (Refereed)
    Abstract [en]

    The lipase chemoselectivity towards an alcohol and a thiol was investigated for the two lipases Candida antarctica lipase B (CalB) and Rhizomucor miehei lipase (Rml). Hexanol and hexanethiol were used as acyl acceptors in a transacylation reaction with ethyl octanoate in cyclohexane. CalB showed the highest chemoselectivity ratio (k(cat)/K-M)(OH)/(k(cat)/K-M)(SH), of 88,000 while the ratio for Rml was 1200. That could be compared with the ratio, k(OH)/k(SH), of 120 for the non-catalyzed reaction. Thus, the enzyme contribution to the chemoselectivity between hexanol and hexanethiol was 730 for CalB and 10 for Rml. High K-M values displayed towards hexanethiol (above 1.8 M) were the largest contribution to the selectivity. No saturation was achieved. The K-M values were more than two orders of magnitude higher than those of hexanol.

  • 20.
    Hedfors, Cecilia
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Takwa, Mohamad
    KTH, School of Biotechnology (BIO), Biochemistry.
    Spinelli, Pietro
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Competition between lactones and polyesters in enzyme catalyzed ring-opening polymerizationManuscript (preprint) (Other academic)
  • 21.
    Hedfors, Cecilia
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Östmark, Emma
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Thiol end-functionalization of poly(epsilon-caprolactone), catalyzed by Candida antarctica lipase B2005In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 38, no 3, p. 647-649Article in journal (Refereed)
    Abstract [en]

    The use of Candida antarctica Lipase B (CALB) chemoselective catalyst in the Thiol End-Functionalization of Poly(ε-caprolacetone) was discussed. Thiol-functionalization of poly(ε-caprolacetone)(PCL) was made by an initiation reaction catalyzed by CALB in bulk. 2-Mercaptoethanol (1) was used to initiate the enzyme-assisted ring opening polymerization of ε-caprolacetone(2) to give the desired thiol-functionalized polymer. The structure of the terminated PCL was confirmed by 13C nuclear magnetic resonance .

  • 22.
    Hendil-Forssell, Peter
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Syren, Per-Olof
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Exploring water as building bricks in enzyme engineering2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 97, p. 17221-17224Article in journal (Refereed)
    Abstract [en]

    A novel enzyme engineering strategy for accelerated catalysis based on redesigning a water network through protein backbone deshielding is presented. Fundamental insight into the energetic consequences associated with the design is discussed in the light of experimental results and computer simulations. Using water as biobricks provides unique opportunities when transition state stabilisation is not easily attained by traditional enzyme engineering.

  • 23.
    Hendil-Forssell, Peter
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Semlitsch, Stefan
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Engineering the esterase/acyltransferase from Mycobacterium smegmatis: extended substrate scope for amide synthesis in waterManuscript (preprint) (Other academic)
    Abstract [en]

    Some esterases/lipases display high acyl transfer activity, favoring alcoholysis over hydrolysis, which make them valuable catalysts for synthesis reactions in aqueous media. An esterase from Mycobacterium smegmatis, MsAcT, has been characterized as an efficient catalyst for ester synthesis in water. The acyl donor specificity for MsAcT was however found to be very narrow and the enzyme displayed no activity towards esters with larger acyl group than butyrate. With rational engineering, the narrow acyl donor specificity of wild type MsAcT enzyme was altered and variants displaying extended substrate scope were generated. A double mutant, T93A/F154A, could accommodate methyl nonanoate as substrate, i.e. five carbons longer acyl group as compared to wild type, without compromising the acyl transfer capabilities. With similar selectivity towards a broad range of acyl donors (propionate to nonanoate) this is a more applicable catalyst than the wild type. Furthermore, the T93A/F154A variant was an efficient catalyst for synthesis of N-benzylhexanamide in water using methyl hexanoate as acyl donor, which is not a substrate for the wild type enzyme. The conversion reached 81% and the enzyme variant could potentially be used to produce amides in water with a wide variety of acyl donors.

  • 24.
    Hendil-Forssell, Peter
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Semlitsch, Stefan
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Rational engineering of an esterase/acyltransferase for improved amidase specificity in amide synthesis and hydrolysisManuscript (preprint) (Other academic)
    Abstract [en]

    The esterase/acyltransferase from Mycobacterium smegmatis, MsAcT, display high acyltransfer capacity in water media with demonstrations found for both ester and amide syntheses. However, it has recently been discovered that esterases in contrast to amidases lack a key hydrogen bond in the transition state, donated by the scissile NH-group of the substrate. Esterases with improved amidase performance have been achieved with the introduction of amino-acid side chains or water network as hydrogen bond acceptors. Using the esterase from Mycobacterium smegmatis, MsAcT, the influence of this hydrogen bond was studied in both amide hydrolysis and synthesis, using a rational engineering approach. Two positions were selected for mutagenesis and enzyme variants with improved performance in amide synthesis and hydrolysis were generated. Compared to the wild-type, variant F154A had the highest absolute increase in amidase specificity (11-fold) and I194Q had the greatest change in relative amidase versus esterase reaction specificity (160-fold). The relative reaction specificities for amide over ester synthesis followed a similar trend as that of hydrolysis and the best variant was I194Q with a 32-fold increase compared to wt. Based on MD-simulations water seems to play an important role in the transition state as a hydrogen bond bridge between the NH-group of the amide substrate and the enzyme.

  • 25. HOLMQUIST, M
    et al.
    MARTINELLE, M
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    CLAUSEN, IG
    PATKAR, S
    SVENDSEN, A
    HULT, K
    TRP89 IN THE LID OF HUMICOLA-LANUGINOSA LIPASE IS IMPORTANT FOR EFFICIENT HYDROLYSIS OF TRIBUTYRIN1994In: Lipids, ISSN 0024-4201, E-ISSN 1558-9307, Vol. 29, no 9, p. 599-603Article in journal (Refereed)
    Abstract [en]

    To determine whether Trp89 located in the lid of the lipase (EC 3.1.1.3) from Humicola lanuginosa is important for the catalytic property of the enzyme, site-directed mutagenesis at Trp89 was carried out. The kinetic properties of wild type and mutated enzymes were studied with tributyrin as substrate. Lipase variants in which Trp89 was changed to Phe, Leu, Gly or Glu all showed less than 14% of the activity compared to that of the wild type lipase. The Trp89Glu mutant was the least active with only 1% of the activity seen with the wild type enzyme. Ah Trp mutants had the same binding affinity to the tributyrin substrate interface as did the wild type enzyme. Wild type lipase showed saturation kinetics against tributyrin when activities were measured with mixed emulsions containing different proportions of tributyrin and the nonionic alkyl polyoxyethylene ether surfactant, Triton DF-16. Wild type enzyme showed a V-max = 6000 +/- 300 mmol.min(-1).g(-1) and an apparent K-m = 16 +/- 2% (vol/vol) for tributyrin in Triton DF-16, while the mutants did not show saturation kinetics in an identical assay. The apparent K-m for tributyrin in Triton DF-16 was increased as the result of replacing Trp89 with other residues (Phe, Leu, Gly or Glu). The activities of all mutants were more sensitive to the presence of Triton DF-16 in the tributyrin substrate than was wild type lipase. The activity of the Trp89Glu mutant was decreased to 50% in the presence of 2 vol% Triton DF-16 compared to the activity seen with pure tributyrin as substrate. Wild type lipase and all mutants except Trp89Glu had the same affinity for the substrate interface formed by 15.6 vol% tributyrin in Triton DF-16. The Trp89Glu mutant showed a lower affinity than all the other lipase variants for the interface of 15.6 vol% tributyrin in Triton DF-16. The study showed that Trp89 located in the lid of H. lanuginosa lipase is important for the efficient hydrolysis of tributyrin and that this residue plays a role in the catalytic steps after adsorption of the lipase to the substrate interface.

  • 26. Holmquist, M.
    et al.
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Berglund, P.
    Mid Sweden University.
    Clausen, I. G.
    Patkar, S.
    Svendsen, A.
    Hult, K.
    Lipases from Rhizomucor miehei and Humicola lanuginosa: Modification of the lid covering the active site alters enantioselectivity1993In: Journal of Protein Chemistry, ISSN 02778033 (ISSN), Vol. 12, no 6, p. 749-757Article in journal (Refereed)
    Abstract [en]

    The homologous lipases from Rhizomucor miehei and Humicola lanuginosa showed approximately the same enantioselectivity when 2-methyldecanoic acid esters were used as substrates. Both lipases preferentially hydrolyzed the S- enantiomer of 1-heptyl 2-methyldecanoate (R. miehei: E(S) = 8.5; H. lanuginosa: E(S) = 10.5), but the R-enantiomer of phenyl 2-methyldecanoate (E(R) = 2.9). Chemical arginine specific modification of the R. miehei lipase with 1,2-cyclohexanedione resulted in a decreased enantioselectivity (E(R) = 2.0), only when the phenyl ester was used as a substrate. In contrast, treatment with phenylglyoxal showed a decreased enantioselectivity (E(S) = 2.5) only when the heptyl ester was used as a substrate. The presence of guanidine, an arginine side chain analog, decreased the enantioselectivity with the heptyl ester (E(S) = 1.9) and increased the enantioselectivity with the aromatic ester (E(R) = 4.4) as substrates. The mutation, Glu 87 Ala, in the lid of the H. lanuginosa lipase, which might decrease the electrostatic stabilization of the open-lid conformation of the lipase, resulted in 47% activity compared to the native lipase, in a tributyrin assay. The Glu 87 Ala mutant showed an increased enantioselectivity with the heptyl ester (E(S) = 17.4) and a decreased enantioselectivity with the phenyl ester (E(R) = 2.5) as substrates, compared to native lipase. The enantioselectivities of both lipases in the esterification of 2-methyldecanoic acid with 1-heptanol were unaffected by the lid modifications.

  • 27.
    Jahic, Mehmedalija
    et al.
    KTH, Superseded Departments (pre-2005), Biotechnology.
    Gustavsson, Malin
    KTH, Superseded Departments (pre-2005), Biotechnology.
    Jansen, Ann-Katrin
    Martinelle, Mats
    KTH, Superseded Departments (pre-2005), Biochemistry and Biotechnology. KTH, Superseded Departments (pre-2005), Biotechnology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Enfors, Sven-Olof
    KTH, Superseded Departments (pre-2005), Biotechnology.
    Analysis and control of proteolysis of a fusion protein in Pichia pastoris fed-batch processes2003In: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 102, no 1, p. 45-53Article in journal (Refereed)
    Abstract [en]

    A fusion protein composed of a cellulose-binding module (CBM) from Neocallimastix patriciarum cellulase 6A and lipase B from Candida antarctica (CALB), was produced by Pichia pastoris Mut(+) in high-cell density bioreactor cultures. The production was induced by switching from growth on glycerol to growth on methanol. The lipase activity in the culture supernatant increased at an almost constant rate up to a value corresponding to 1.3 g l(-1) of CBM-CALB. However, only about 40% of the product was of full-length according to Western blot analysis. This loss was due to a cleavage of the protein in the linker between the CBM and the CALB moieties. The cleavage was catalyzed by serine proteases in the culture supernatant. The CALB-moiety was subjected to further slow degradation by cell-associated proteolysis. Different strategies were used to reduce the proteolysis. Previous efforts to shorten the linker region resulted in a stable protein but with ten times reduced product concentration in bioreactor cultures (Gustavsson et al. 2001, Protein Eng. 14, 711-715). Addition of rich medium for protease substrate competition had no effect on the proteolysis of CBM-CALB. The kinetics for the proteolytic reactions, with and without presence of cells were shown to be influenced by pH. The fastest reaction, cleavage in the linker, was substantially reduced at pH values below 5.0. Decreasing the pH from 5.0 to 4.0 in bioreactor cultures resulted in an increase of the fraction of full-length product from 40 to 90%. Further improvement was achieved by decreasing the temperature from 30 to 22 degreesC during the methanol feed phase. By combining the optimal pH and the low temperature almost all product (1.5 g l(-1)) was obtained as full-length protein with a considerably higher purity in the culture supernatant compared with the original cultivation.

  • 28.
    Jahic, Mehmedalija
    et al.
    KTH, Superseded Departments, Biotechnology.
    Rotticci-Mulder, Johanna C.
    Martinelle, Mats
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    Hult, Karl
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    Enfors, Sven-Olof
    KTH, Superseded Departments, Biotechnology.
    Modeling of growth and energy metabolism of Pichia pastoris producing a fusion protein2002In: Bioprocess and biosystems engineering (Print), ISSN 1615-7591, E-ISSN 1615-7605, Vol. 24, no 6, p. 385-393Article in journal (Refereed)
    Abstract [en]

    A fusion protein composed of a cellulose binding domain from Neocallimastix patriciarum cellulase A and Candida antarctica lipase B (CBD-lipase) was produced by Pichia pastoris methanol utilization plus phenotype in high cell-density cultures. The genes expressing CBD-lipase were fused to the alpha-factor secretion signal sequence of Saccharomyces cerevisiae and placed under the control of the alcohol oxidase gene (AOX1) promoter. To control the repression and induction of AOX1 and oxygen demand at high cell density, a four-stage process was used. Batch growth on glycerol was used in the first step to provide biomass (28 g L-1) while product formation was prevented due to repression of the AOX1. The second stage was exponential fed-batch growth on glycerol, which caused a slight increase of the enzyme alcohol oxidase activity due to derepression of the AOX1. This procedure resulted in smooth transition to exponential fed-batch growth on methanol, the third stage, in which the AOX1 was strongly induced. The fourth stage was constant fed-batch growth on methanol used to control the oxygen demand at the high cell density. A kinetic model was developed that could predict biomass growth and oxygen consumption in processes with and without oxygen-enriched air. With oxygen enrichment to 34% O-2 in the inlet air the methanol feed rate could be increased by 50% and this resulted in 14% higher final cell density (from 140 to 160 g L-1 cell dry weight). The increased methanol feed rate resulted in a proportionally increased specific rate of product secretion to the medium. After an initial decrease, the synthesis capacity of the cell was kept constant throughout the cultivation, which made the product concentration increase almost constantly during the process. The kinetic model also describes how the low maintenance demand of P. pastoris compared with E. coli enables this organism to grow to such high cell densities.

  • 29.
    Land, Henrik
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Hendil-Forssell, Peter
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    One-pot biocatalytic amine transaminase/acyl transferase cascade for aqueous formation of amides from aldehydes or ketones2016In: catalysis science & technology, ISSN 2044-4753, Vol. 6, p. 2897-2900Article in journal (Refereed)
    Abstract [en]

    An efficient one-pot one-step biocatalytic amine transaminase/acyl transferase cascade for the formation of amides from the corresponding aldehydes and ketones in aqueous solution has been developed. N-benzyl-2-methoxyacetamide has been synthesized utlilizing the developed cascade in conversions up to 97%. The cascade was also evaluated for the synthesis of chiral amides.

  • 30.
    Larsen, Marianne Wittrup
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Zielinska, Dorota F.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hidalgo, Aurelio
    Jensen, Lars Juhl
    Bornscheuer, Uwe T.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Suppression of Water as a Nucleophile in Candida antarctica Lipase B Catalysis2010In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 11, no 6, p. 796-801Article in journal (Refereed)
    Abstract [en]

    A water tunnel in Candida antarctica lipase B that provides the active site with substrate water is hypothesized. A small, focused library created in order to prevent water from entering the active site through the tunnel was screened for increased transacylation over hydrolysis activity. A single mutant, S47L, in which the inner part of the tunnel was blocked, catalysed the transacylation of vinyl butyrate to 20 mm butanol 14 times faster than hydrolysis. The single mutant Q46A, which has a more open outer end of the tunnel, showed an increased hydrolysis rate and a decreased hydrolysis to transacylation ratio compared to the wild-type lipase. Mutants with a blocked, tunnel could be very useful in applications in which hydrolysis is unwanted, such as the acylation of highly hydrophilic compounds in the presence of water.

  • 31.
    Martinelle, M
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Holmquist, M
    Clausen, I G
    Patkar, S
    Svendsen, A
    Hult, K
    The role of Glu87 and Trp89 in the lid of Humicola lanuginosa lipase1996In: Protein Engineering, ISSN 0269-2139, E-ISSN 1460-213X, Vol. 9, no 6, p. 519-524Article in journal (Refereed)
    Abstract [en]

    The importance of Glu87 and TRp89 in the lid of Humicola lanuginosa lipase for the hydrolytic activity at the water/lipid interface was investigated by site-directed mutagenesis. It was found that the effect on the hydrolytic activity upon the replacement of Trp89 with Phe, Leu, Gly or Glu was substrate dependent, The Trp89 mutants displayed an altered chain length specificity towards triglycerides, with a higher relative activity towards triacetin and trioctanoin compared with tributyrin, Trp89 was shown to be less important in the hydrolysis of vinyl esters compared with ethyl esters and triglycerides. An exclusive effect on the acylation reaction rate by the mutation of Trp89 was consistent with the data, It is suggested that Trp89 is important in the process of binding the acyl chain of the substrate into the active site for optimal acylation reaction rate, The Trp89Phe mutation resulted in an increased hydrolytic activity towards 2-alkylalkanoic acid esters. This is suggested to be due to reduction of unfavourable van der Waals contacts between Trp89 and the 2-substituent of the substrate, Thus, in contrast to natural substrates, Trp89 has a negative impact on the catalytic efficiency when substrates with bulky acyl chains are used, In contrast to the Trp89 mutations, the effect on the hydrolytic activity of the Glu87Ala mutation was almost substrate independent, 35-70% activity of wild-type lipase, A reduction of both the acylation and deacylation reaction was consistent with the data.

  • 32.
    MARTINELLE, M
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    HOLMQUIST, M
    HULT, K
    ON THE INTERFACIAL ACTIVATION OF CANDIDA-ANTARCTICA LIPASE-A AND LIPASE-B AS COMPARED WITH HUMICOLA-LANUGINOSA LIPASE1995In: BIOCHIMICA ET BIOPHYSICA ACTA-LIPIDS AND LIPID METABOLISM, ISSN 0005-2760, Vol. 1258, no 3, p. 272-276Article in journal (Refereed)
    Abstract [en]

    The interfacial activation of Candida antarctica lipase A (CALA) and B (CALB) has been investigated and compared with that of Humicola lanuginosa lipase (HLL). CALB displayed no interfacial activation towards p-nitrophenyl butyrate (PNPB) when exceeding the solubility limit of the substrate. No activation was observed towards p-nitrophenyl acetate (PNPA) at the addition of sodium dodecyl sulfate (SDS) nor in the presence of a solid polystyrene surface. The catalytic action of CALB was very different from that of Humicola lanuginosa lipase, which showed a pronounced interfacial activation with the same substrates. The basis for the anomalous behaviour of CALB is proposed to be due to the absence of a lid that regulates the access to the active site. in contrast to CALB, CALA expressed interfacial activation, but the activation was not as prominent as for Humicola lanuginosa lipase (HLL). The structural basis for the activation of CALA is unknown.

  • 33.
    MARTINELLE, M
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    HULT, K
    KINETICS OF ACYL TRANSFER-REACTIONS IN ORGANIC MEDIA CATALYZED BY CANDIDA-ANTARCTICA LIPASE-B1995In: Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology, ISSN 0167-4838, E-ISSN 1879-2588, Vol. 1251, no 2, p. 191-197Article in journal (Refereed)
    Abstract [en]

    The acyl transfer reactions catalysed by Candida antarctica lipase B in organic media followed a bi-bi ping-pong mechanism, with competitive substrate inhibition by the alcohols used as acyl accepters. The effect of organic solvents on V-m and K-m was investigated. The V-m values in acetonitrile was 40-50% of those in heptane. High K-m values in acetonitrile compared to those in heptane could partly be explained by an increased solvation of the substrates in acetonitrile. Substrate solvation caused a 10-fold change in substrate going from heptane to acetonitrile. Deacylation was the rate determining specificity, defined as (V-m/K-m)(ethyl) (octanoate)/(V-m/K-m)(octanoic) (acid), step for the acyl transfer in heptane with vinyl- and ethyl octanoate as acyl donors and (R)-2-octanol as acyl acceptor. With I-octanol, a rate determining deacylation step in heptane was indicated using the same acyl donors. Using I-octanol as acceptor in heptane, S-ethyl thiooctanoate had a 25- to 30-fold lower V-m/K-m value and vinyl octanoate a 4-fold higher V-m/K-m value than that for ethyl octanoate. The difference showed to be a K-m effect for vinyl octanoate and mainly a K-m effect for S-ethyl thiooctanoate. The V-m values of the esterification of octanoic acid with different alcohols was 10-30-times lower than those for the corresponding transesterification of ethyl octanoate. The low activity could be explained by a low pH around the enzyme caused by the acid or a withdrawing of active enzyme by nonproductive binding by the acid.

  • 34.
    Nameer, Samer
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Semlitsch, Stefan
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    One-pot enzyme-catalyzed synthesis of dual-functional polyester macromers towards surface active hydrophobic filmsManuscript (preprint) (Other academic)
    Abstract [en]

    Selective enzyme catalysis is a valuable tool for the processing of monomers into value-added materials. In the present study natural resources were used to retrieve an ω-hydroxy fatty acid monomer containing an epoxide functionality. A procedure was developed for the synthesis of dual-functional oligomers by utilizing lipase catalysis in a one-pot synthesis route. The chemoselectivity of the enzyme allowed addition of thiol monomers to the retrieved epoxy monomers, without harming the epoxides, achieving a thiol-epoxy functional polyester resin. The synthesis reached full conversion (>99 %) after 8 h. It was possible to selectively crosslink the resin, through UV-initiated cationic polymerization of the epoxides into thiol-functional thermosets. The curing performance was followed in situ by Real-Time FTIR. The thiol groups on the surface of the film were accessible for post-modification.

  • 35.
    Nameer, Samer
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Semlitsch, Stefan
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    One-pot enzyme-catalyzed synthesis of dual-functional polyester macromers towards surface-active hydrophobic films2017In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 79, p. 50294-50299Article in journal (Refereed)
    Abstract [en]

    Selective enzyme catalysis is a valuable tool for the processing of monomers into value-added materials. In the present study natural resources were used to retrieve an omega-hydroxy fatty acid monomer containing an epoxide functionality. A procedure was developed for the synthesis of dual-functional oligomers by utilizing lipase catalysis in a one-pot synthesis route. The chemoselectivity of the enzyme allowed addition of thiol monomers to the retrieved epoxy monomers, without harming the epoxides, achieving a thiol-epoxy functional polyester resin. The synthesis reached full conversion (> 99%) after 8 h. It was possible to selectively crosslink the resin through UV-initiated cationic polymerization of the epoxides into thiol-functional thermosets. The curing performance was followed in situ by real-time FTIR. The thiol groups on the surface of the film were accessible for post-modification.

  • 36. OHRNER, N
    et al.
    Martinelle, Mats
    KTH, Superseded Departments (pre-2005), Biochemistry and Biotechnology.
    MATTSON, A
    NORIN, T
    HULT, K
    THIOETHYL-OCTANOATE, VINYL-OCTANOATE, ETHYL-OCTANOATE ESTERS AND OCTANOIC-ACID AS ACYL DONORS IN LIPASE-CATALYZED ACYL TRANSFER-REACTIONS1994In: BIOCATALYSIS, ISSN 0886-4454, Vol. 9, no 1-4, p. 105-114Article in journal (Refereed)
    Abstract [en]

    S-Ethyl thiooctanoate, vinyl octanoate, ethyl octanoate and octanoic acid were studied as acyl donors in a lipase catalysed acyl transfer reaction with 2-octanol as acyl acceptor. The reaction conditions had a pronounced effect on the equilibrium displacement and the apparent enantioselectivity. The thioethyl and vinyl esters proved to be efficient acyl donors under atmospheric pressure and 39-degrees-C, affording a high apparent enantiomeric ratio. Under these reaction conditions the apparent enantioselectivity seemed to be enhanced by water, which was present in the reaction system and caused the production of octanoic acid, by hydrolysis of the acyl enzyme.

  • 37. Rotticci, D.
    et al.
    Norin, T.
    Hult, Karl
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    Martinelle, Mats
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    An active-site titration method for lipases2000In: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids, ISSN 1388-1981, E-ISSN 1879-2618, Vol. 1483, no 1, p. 132-140Article in journal (Refereed)
    Abstract [en]

    A method for active-site titration of lipases has been developed based on irreversible inhibition by methyl p-nitrophenyl n-hexylphosphonate. This method was applied to five lipases displaying from minor to pronounced interfacial activation. Soluble and immobilized lipases were successfully titrated in aqueous media. A low concentration of sodium dodecyl sulfate was needed for lipases displaying pronounced interfacial activation. The carrier of some of the immobilized preparations adsorbed part of the produced p-nitrophenolate, This problem could be solved by extracting the p-nitrophenolate after inhibition. The method was extended to apolar organic solvents in the case of immobilized lipase preparations.

  • 38. Rotticci-Mulder, J. C.
    et al.
    Gustavsson, M.
    Holmquist, M.
    Hult, Karl
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    Martinelle, Mats
    KTH, Superseded Departments, Biochemistry and Biotechnology.
    Expression in Pichia pastoris of Candida antarctica lipase B and lipase B fused to a cellulose-binding domain2001In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 21, no 3, p. 386-392Article in journal (Refereed)
    Abstract [en]

    Candida antarctica lipase B (CALB) and C. antarctica lipase B fused to a cellulose-binding domain (CBD-CALB) were expressed functionally in the methylotrophic yeast Pichia pastoris. The cellulose-binding domain originates from cellulase A of the anaerobic rumen fungus Neocallimastix patriciarum. The genes were fused to the a-factor secretion signal sequence of Saccharomyces cerevisiae and placed under the control of the alcohol oxidase gene (AOX1) promoter. The recombinant proteins were secreted into the culture medium reaching levels of approximately 25 mg/L. The proteins were purified using hydrophobic interaction chromatography and gel filtration with an overall yield of 69%. Results from endoglycosidase H digestion of the proteins showed that CALB and CBD-CALB were N-glycosylated. The specific hydrolytic activities of recombinant CALB and CBD-CALB were identical to that reported for CALB isolated from its native source. The fusion of the CBD to the lipase resulted in a greatly enhanced binding toward cellulose for CBD-CALB compared with that for CALB.

  • 39.
    Rüdiger, Arne
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hendil-Forssell, Peter
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Hedfors, Cecilia
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Trey, Stacy
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. SP Trätek, SP Technical Research Institute of Sweden.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Chemoenzymatic Route to Renewable Thermosets Based on a Suberin Monomer2013In: Journal of renewable materials, ISSN 2164-6341, Vol. 1, no 2, p. 124-140Article in journal (Refereed)
    Abstract [en]

    The present study describes the use of an epoxy functional fatty acid, 9,10-epoxy-18-hydroxyoctadecanoic acid (EFA), extracted from birch (Betula pendula) outer bark to produce thermosets. The purified epoxy fatty acid was polymerized by enzyme-catalyzed polycondensation utilizing Candida antarctica lipase B (CalB) to form oligomers with targeted degrees of polymerization (DP) of 3, 6, and 9 and obtained DPs of 2.3, 5.9 and 7.3, respectively. It was determined that it is possible to first enzymatically polymerize and aliphatically endcap the epoxy functional fatty acid resulting in controlled oligomer lengths while also maintaining the epoxy functionality for further reaction by main-chain homo-epoxy cationic photopolymerization. The enzymatic polymerized oligomers were characterized in terms of conversion of the residual epoxy groups (FT-IR), the thermal properties (DSC, TGA) and the purity by MALDI-TOF and 1H-NMR. The amorphous thermoset films with varying degrees of crosslinking resulting from the cationically photopolymerized oligomers, were characterized in terms of their thermal properties and residual epoxy content (FT-IR ATR). The crosslinked polyesters formed insoluble, amorphous, and transparent films. This work demonstrates that thermoset films with designed properties can be effectively made with the use of forest products to reduce the petroleum-based plastics market.

  • 40.
    Semlitsch, Stefan
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Mixed vinyl adipate esters through selective synthesis using a designed esterase/acyltransferaseManuscript (preprint) (Other academic)
    Abstract [en]

    Methods for selective syntheses of mixed dicarboxylic esters from symmetrical diesters are of great interest. An esterase from Mycobacterium smegmatis, MsAcT, has shown to be an efficient catalyst for acyl transfer reactions using both alcohols and amines. It has a restricted active site resulting in a narrow acyl donor specificity. This limitation was used for the development of a selective synthesis of mixed vinyl adipate esters from divinyl adipate. The single mutant, L12A, achieved over 90% conversion of divinyl adipate with three different alcohols leading to the corresponding mixed vinyl adipate esters. This method allows the synthesis of vinyladipoyl esters at mild reaction conditions.

  • 41.
    Semlitsch, Stefan
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Torron, Susana
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Enzymatic catalysis as a versatile tool for the synthesis of multifunctional, bio-based oligoester resins2016In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 18, no 7, p. 1923-1929Article in journal (Refereed)
    Abstract [en]

    The use of enzymes as selective catalysts for processing renewable monomers into added value polymers and materials has received increased attention during the last decade. In the present work Candida antarctica lipase B (CalB) was used as catalyst in one-pot routes to synthesise multifunctional oligoester resins based on an epoxy-functional omega-hydroxy-fatty acid (EFA) extracted from birch bark. The chemoselective enzymatic process resulted in three different EFA-based telechelic oligomers with targeted molecular weights; containing maleimide, methacrylate or oxetane as end-groups, respectively. The enzyme catalysed synthesis of the maleimide and the oxetane telechelic oligomers reached full conversion of monomers (>95%) after 2 h. In the case of methacrylate functional oligomer the EFA monomer reached full conversion (>98%) after 2 h but the integration of the methacrylate moiety took more than 10 h. This was due to a rate limiting reaction path using ethylene glycol dimethacrylate as substrate. The oligomer products were characterised by NMR, MALDI-TOF-MS and SEC.

  • 42.
    Simpson, Neil
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Takwa, Mohamad
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Johansson, Mats K. G.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Thiol-functionalized poly(omega-pentadecalactone) telechelics for semicrystalline polymer networks2008In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 41, no 10, p. 3613-3619Article in journal (Refereed)
    Abstract [en]

    Semicrystalline macromonomers based on poly(pentadecalactone), PPDL, have been synthesized by the lipase-catalyzed ring-opening of the otherwise chemically inert pentadecalactone monomer. The macromonomers were designed to have reactive thiols as end groups by the appropriate choice of initiator and chain terminator. The thiol functional macromonomers were then used together with ene monomers to give crosslinked thin films after irradiation in the molten state by UV light in the presence of a photoinitiator (Irgacure 65 1). Two different ene monomers were used, i.e., a tetrafunctional norbornene species and a trifunctional allyl ether maleate species, and resulted in semicrystalline cured films when cured with PPDL. An amorphous, commercially available, trifunctional thiol, trimethylolpropane tri(3-mercaptopropionate), TRIS, was also used for network formation in order to better understand the effect of crystallinity. All thiol-ene systems were found to be readily photopolymerised to high conversion. The PPDL-based networks were semicrystalline in the crosslinked state where the degree of crystallinity was found to depend on the nature of the cross-linker. Networks based on TRIS were found to be amorphous.

  • 43.
    Syrén, Per-Olof
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Hendil-Forssell, Peter
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Aumailley, Lucie
    Besenmatter, Werner
    Gounine, Farida
    Svendsen, Allan
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry (closed 20130101).
    Esterases with an Introduced Amidase-Like Hydrogen Bond in the Transition State Have Increased Amidase Specificity2012In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 13, no 5, p. 645-648Article in journal (Refereed)
  • 44.
    Takwa, Mohamad
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Single-step, solvent-free enzymatic route to alpha,omega-functionalized polypentadecalactone macromonomers2008In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 41, no 14, p. 5230-5236Article in journal (Refereed)
    Abstract [en]

    A straightforward enzymatic single-step route toward the synthesis of alpha,omega-functionalized polypentadecalactone (PPDL) macromonomers containing dithiol, thiol-acrylate, diacrylate, or dimethacrylate end groups has been developed. Two solvent-free approaches, mixing all components at start, using Candida antarctica lipase B (CALB) as an efficient catalyst were demonstrated. In the first approach difunctionalized polymers (with dithiol or thiol-acrylate end groups) were synthesized by mixing lipase, lactone, and equimolar amounts of functional initiator (6-mercapto-1-hexanol) and terminator (11-mercapto-1-undecanoic acid or vinyl acrylate). Polymers with a high fraction (95%) of dithiol end groups or polymers with thiol-acrylate end groups (86% and 96%, respectively) were obtained. In the second approach, a functional diester (ethylene glycol diacrylate or ethylene glycol dimethacrylate) was mixed with lactone and lipase without predrying, using water as an initial initiator. Reduced pressure was applied after 2 h of incubation to evaporate water and push the equilibrium toward high functionalization. Polymers with >96% diacrylated or dimethacrylated end groups were achieved.

  • 45.
    Takwa, Mohamad
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Simpson, Neil
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    One-Pot Difunctionalization of Poly-(ω-pentadecalactone) with Thiol-Thiol or Thiol-Acrylate Groups, Catalyzed by Candida antarctica Lipase B2006In: Macromolecular rapid communications, ISSN 1022-1336, E-ISSN 1521-3927, Vol. 27, no 22, p. 1932-1936Article in journal (Refereed)
    Abstract [en]

    An enzymatic one-pot procedure has been developed for the synthesis of difunetional polyesters containing terminal thiols and acrylates. Candida antarctica lipase B was used as a catalyst for the ring-opening polymerization of ω-pentadecalactone. The polymerization was initiated with 6-mercaptohexanol, then terminated with γ-thiobutyrolactone or vinyl acrylate to create two types of difunetional polyesters with a very high content of thiol-thiol or thiolacrylate end-groups.

  • 46.
    Takwa, Mohamad
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Wittrup Larsen, Marianne
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Rational redesign of Candida antarctica lipase B for the ring opening polymerization of D,D-lactide2011In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, no 26, p. 7392-7394Article in journal (Refereed)
    Abstract [en]

    Based on molecular modelling, the enzyme Candida antarctica lipase B was redesigned as a catalyst for the ring opening polymerization of D, D-lactide. Two mutants with 90-fold increased activity as compared to the wild-type enzyme were created. In a preparative synthesis of poly(D,D-lactide) the mutants greatly improved the rate and the degree of polymerization.

  • 47.
    Takwa, Mohamad
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Xiao, Yan
    Simpson, Neil
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malmström, Eva M.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Koning, Cor.
    Heise, Andreas
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Biochemistry.
    Lipase Catalyzed HEMA Initiated Ring-Opening Polymerization: In Situ Formation of Mixed Polyester Methacrylates by Transesterification2008In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 9, no 2, p. 704-710Article in journal (Refereed)
    Abstract [en]

    2-Hydroxyethyl methacrylate (HEMA) was used as initiator for the enzymatic ring-opening polymerization (ROP) of ω-pentadecalactone (PDL) and ∈-caprolactone (CL). The lipase B from Candida antarctica was found to catalyze the cleavage of the ester bond in the HEMA end group of the formed polyesters, resulting in two major transesterification processes, methacrylate transfer and polyester transfer. This resulted in a number of different polyester methacrylate structures, such as polymers without, with one, and with two methacrylate end groups. Furthermore, the 1,2-ethanediol moiety (from HEMA) was found in the polyester products as an integral part of HEMA, as an end group (with one hydroxyl group) and incorporated within the polyester (polyester chains acylated on both hydroxyl groups). After 72 h, as a result of the methacrylate transfer, 79% (48%) of the initial amount of the methacrylate moiety (from HEMA) was situated (acylated) on the end hydroxyl group of the PPDL (PCL) polyester. In order to prepare materials for polymer networks, fully dimethacrylated polymers were synthesized in a one-pot procedure by combining HEMA-initiated ROP with end-capping using vinyl methacrylate. The novel PPDL dimethacrylate (>95% incorporated methacrylate end groups) is currently in use for polymer network formation. Our results show that initiators with cleavable ester groups are of limited use to obtain well-defined monomethacrylated macromonomers due to the enzyme-based transesterification processes. On the other hand, when combined with end-capping, well-defined dimethacrylated polymers (PPDL, PCL) were prepared.

  • 48.
    Torron, Susana
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Johansson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Malmström, Eva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Fogelström, Linda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hult, Karl
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Telechelic polyesters and polycarbonates prepared by enzymatic catalysis2017In: Handbook of Telechelic Polyesters, Polycarbonates, and Polyethers, Pan Stanford Publishing Pte. Ltd. , 2017, p. 29-64Chapter in book (Other academic)
    Abstract [en]

    The majority of polyesters and polycarbonates are traditionally synthesized through conventional metal-based catalysis. Although effective, due to environmental concerns, their substitution for other more environmentally friendly alternatives has received increasing interest during the last decades. The search for catalytic systems that also allow milder reaction conditions has been intensified, owing to 30the unwanted side reactions, for example, backbone scissoring, that the metal-based catalysts may cause [1]. In this context, enzymes are anticipated as suitable alternatives [2,3,4,5,6,7,-8]. 

  • 49.
    Torron, Susana
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Semlitsch, Stefan
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinell, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Biocatalytic Synthesis of Epoxy Resins from Fatty Acids as a Versatile Route for the Formation of Polymer Thermosets with Tunable Properties2016In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, no 12, p. 4003-4010Article in journal (Refereed)
    Abstract [en]

    The work herein presented describes the synthesis and polymerization of series of bio-based epoxy resins prepared through lipase catalyzed transesterification. The epoxy-functional polyester resins with various architectures (linear, hi branched, and tetra-branched) were synthesized through condensation of fatty acids derived from epoxidized soybean oil and linseed oil with three different hydroxyl cores under bulk conditions. The selectivity of the lipases toward esterification/transesterification reactions allowed the formation of macromers with up to 12 epoxides in the backbone. The high degree of functionality of the resins resulted in polymer thermosets with T-g values ranging from 25 to over 100 degrees C prepared through cationic polymerization. The determining parameters of the synthesis and the mechanism for the formation of the species were determined through kinetic studies by H-1 NMR, SEC, and molecular modeling studies. The correlation between macromer structure and thermoset properties was studied through real-time FTIR measurements, DSC, and DMA.

  • 50.
    Torron, Susana
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Semlitsch, Stefan
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Polymer Thermosets from Multifunctional Polyester Resins Based on Renewable Monomers2014In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 215, no 22, p. 2198-2206Article in journal (Refereed)
    Abstract [en]

    The use of monomers based on natural materials as a future supply of raw materials has gained more interest in the last decade. Sources ranging from wood to plant oils and algae are exploited as alternatives to traditional fossil-based resources for the synthesis of polymeric materials. The use of these raw materials is not only of interest because of its abundance, but also in terms of price, durability, and/or biodegradability. In the present study, a series of resins utilizing a monomer derived from birch bark is prepared. The thermoset resins are formed by reacting an epoxy-functional omega-hydroxy fatty acid with methacrylate monomers using enzyme catalysis to form multifunctional resins via a one-pot synthesis. The derived oligomers are crosslinked through different polymerization routes to produce thermosets with different properties and/or functionalities. This approach allows natural-based resins with tuned functionalities and mechanical and thermal properties to be obtained.

12 1 - 50 of 54
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