Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

    Current refinement(s):

    Records 1 - 20 / 51

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    Bioplastics voor herstel ecosystemen
    Molenveld, K. - \ 2018
    Wageningen : Wageningen Food & Biobased Research
    biobased economy - bioplastics - biobased materials - biopolymers - ecosystems - biomass - residual streams - organic wastes
    Stof tot nadenken: vier manieren om de mode-industrie duurzamer te maken
    Louwerens, Tessa ; Poldner, Kim ; Fischer, A.R.H. ; Broek, L.A.M. van den; Dam, J.E.G. van; Houthoff, Iris - \ 2018
    biobased materials - clothing - fibres - algae - biomass - hemp - dyes - pigments - bioplastics - biopolymers - ink - natural products
    Biocatalytic Route for the Synthesis of Oligoesters of Hydroxy-Fatty acids and ϵ-Caprolactone
    Todea, Anamaria ; Aparaschivei, Diana ; Badea, Valentin ; Boeriu, Carmen G. ; Peter, Francisc - \ 2018
    Biotechnology Journal 13 (2018)6. - ISSN 1860-6768
    biocatalysis - biopolymers - hydroxy-fatty acids - lipase - ϵ-caprolactone

    Developments of past years placed the bio-based polyesters as competitive substitutes for fossil-based polymers. Moreover, enzymatic polymerization using lipase catalysts has become an important green alternative to chemical polymerization for the synthesis of polyesters with biomedical applications, as several drawbacks related to the presence of traces of metal catalysts, toxicity and higher temperatures could be avoided. Copolymerization of ϵ-caprolactone (CL) with four hydroxy-fatty acids (HFA) from renewable sources, 10-hydroxystearic acid, 12-hydroxystearic acid, ricinoleic acid, and 16-hydroxyhexadecanoic acid, was carried out using commercially available immobilized lipases from Candida antarctica B, Thermomyces lanuginosus, and Pseudomonas stutzeri, as well as a native lipase. MALDI-TOF-MS and 2D-NMR analysis confirmed the formation of linear/branched and cyclic oligomers with average molecular weight around 1200 and polymerization degree up to 15. The appropriate selection of the biocatalyst and reaction temperature allowed the tailoring of the non-cyclic/cyclic copolymer ratio and increase of the total copolymer content in the reaction product above 80%. The catalytic efficiency of the best performing biocatalyst (Lipozyme TL) is evaluated during four reaction cycles, showing excellent operational stability. The thermal stability of the reaction products is assessed based on TG and DSC analysis. This new synthetic route for biobased oligomers with novel functionalities and properties could have promising biomedical applications.

    'Veelbelovend en bijna marktrijp' : onderzoek door Wageningen Universiteit Research naar biobased bindmiddelen in verf
    Haveren, J. van - \ 2017
    residual streams - biobased economy - chemicals - biobased chemicals - research - biobased chemistry - binding agents - biopolymers - paints
    PHA’s (Polyhydroxyalkanoates): General information on structure and raw materials for their production : A running document for “Kleinschalige Bioraffinage WP9: PHA”, Task 5
    Kootstra, A.M.J. ; Elissen, H.J.H. ; Huurman, Sander - \ 2017
    Lelystad : Wageningen UR, PPO/Acrres (Wageningen Plant Research report 727) - 29
    biopolymers - biorefinery - polyhydroxyalkanoates - residual streams - bioprocess engineering - biobased chemistry - biobased economy - biopolymeren - bioraffinage - polyhydroxyalkanoaten - reststromen - bioproceskunde - chemie op basis van biologische grondstoffen - biobased economy
    This report provides background information on structure and diversity of different polyhydroxyalkanoates (PHA) and on feedstocks for their microbial production. The information that is contained in this report was compiled as a running document for the project “TKI-AgriFood Kleinschalige Bioraffinage” Work Package 9: “Fatty acid and PHA production based on residues” (In Dutch: “Vetzuuren PHA-productie op basis van residuen”) (TKI-AF-12040), and should be seen as such: a compilation of information regarded as interesting for the project partners.
    PPS Innovatie slag groeisubstraat tuinbouwketen. Deelproject 1 BioFoam als substraat : Resultaten 2015
    Baltissen, A.H.M.C. - \ 2016
    Randwijk : Wageningen Plant Research , onderdeel van Wageningen University & Research, Business Unit Bloembollen, Boomkwekerij en Fruit (Praktijkonderzoek Plant & Omgeving rapport 2016-02) - 19
    biopolymeren - schuimplastic - productontwikkeling - substraten - vervangmiddelen - materialen uit biologische grondstoffen - biobased economy - bos- en haagplantsoen - boomteelt - naaldbomen als sierplanten - levermossen - biopolymers - plastic foam - product development - substrates - substitutes - biobased materials - biobased economy - woody nursery stock - arboriculture - ornamental conifers - liverworts
    BioFoam® zijn geschuimde bolletjes (vergelijkbaar met piepschuim) die worden gemaakt op basis van Polymelkzuur (PLA). PLA is een polymeer (plastic) dat gemaakt wordt uit hernieuwbare grondstoffen zoals mais zetmeel of suikerstroop (uit bijvoorbeeld suikerriet). PLA is 100% hernieuwbaar en volledig biologisch afbreekbaar. Dit project “BioFoam als substraat” is een onderdeel van de PPS “Innovatie slag groeisubstraat tuinbouw keten” en heeft de focus op de inzet BioFoam® als onderdeel van substraat in de boomkwekerij. Dit rapport beschrijft de resultaten van de proef te PPO Randwijk in 2015.
    From Beet Pulp To Building Blocks and Polymers Developing Value Added Materials From GalX
    Leeuwen, M.B. van; Gootjes, L. ; Vogelzang, W. ; Knoop, J.R.I. ; Haveren, J. van; Es, D.S. van - \ 2016
    biobased economy - materialen uit biologische grondstoffen - reststromen - agrarische afvalstoffen - biopolymeren - galacturonzuur - bietenpulp - bioplastics - biobased economy - biobased materials - residual streams - agricultural wastes - biopolymers - galacturonic acid - beet pulp - bioplastics
    Poster of the Carbohydrate Competence Center. The increasing demand for 2nd generation bio-based performance materials presents an excellent opportunity for the development of agricultural residues like sugar beet pulp (SBP) as feedstock for renewable polymers. Refining SBP yields various industrially interesting components, such as galacturonic acid. This sugar acid can be transformed into a novel family of bio-based building blocks called GalX. Here we report on the use of GalX building blocks in bio-based polymers.
    Biobased chemicals from polyhydroxybutyrate
    Spekreijse, Jurjen - \ 2016
    Wageningen University. Promotor(en): Johan Sanders, co-promotor(en): Elinor Scott; Harry Bitter. - Wageningen : Wageningen University - ISBN 9789462578630 - 148
    bioprocess engineering - biopolymers - waste water treatment - polyhydroxyalkanoates - acrylics - propylene - biomass conversion - biobased chemistry - biobased economy - bioproceskunde - biopolymeren - afvalwaterbehandeling - polyhydroxyalkanoaten - acrylaten - propyleen - biomassaconversie - chemie op basis van biologische grondstoffen - biobased economy

    Currently, most chemicals and materials are obtained from fossil resources. After use, these chemicals and materials are converted to CO2. As discussed in chapter 1, this causes a build-up of CO2 in the atmosphere, the main driving force of global warming. In order to reach a sustainable system, biomass could be used as a resource for chemicals and materials instead. A biorefinery approach, where all parts of biomass are used to its full potential is essential. Taking this into consideration, wastewater streams of current biobased processes could be an excellent source for chemicals and materials. However, wastewater is often dilute and heterogeneous of nature. To overcome these challenges, wastewater rich in carbon can be processed by microorganisms to obtain a biodegradable polyester, polyhydroxyalkanoate (PHA). However, the mechanical properties of this polymer make it unsuitable as polymeric material. Moreover, processing of PHA is challenging. To circumvent these issues, we propose a conversion of the inferior PHA to methyl acrylate and propylene (Figure 7.1) which can be used in current processing infrastructure. PHA rich cells are obtained from the purification of wastewater. The PHA obtained can be purified and converted to MC (Figure 7.1, chapter 2) or the PHA rich cells can be used directly (Figure 7.1, chapter 3). For the second step, the conversion of methyl crotonate (MC) to methyl acrylate and propylene, the catalyst was immobilised (Figure 7.1, chapter 4). The current state of ethenolysis reaction on biomass was reviewed (Figure 7.1, chapter 5). The conversion of PHA to methyl acrylate and propylene enables the use of carbon from wastewater streams without the disadvantages related to the direct use of PHA.

    In chapter 2, the first step of the conversion of PHA to methyl acrylate and propylene was investigated. Since PHA obtained from wastewater exists mostly as polyhydroxybutyrate (PHB), this was chosen as a starting material for our studies. It was shown that PHB could be converted to MC using methanol at 200 °C.. MC has the advantage of being immiscible with water, which aids its separation. In chapter 2, the pathway of the reaction was clarified, which was subsequently used to optimise the conditions of this conversion. The conversion of PHB to MC proceeds via a thermolysis to crotonic acid (CA), which is followed by an esterification to MC. The formation of CA is the rate determining step below 18 bar, where above 18 bar this changes to the esterification to MC. A selectivity of 60% to MC is obtained with a full conversion of PHB with 18 bar being the optimal pressure for the conversion.

    Microorganisms produce PHA within their cells, which poses challenges to the downstream processing of PHA as the material has to be isolated from within the cells and dried. The isolation and drying of PHB is costly and is responsible for a large part of the production costs of PHA. In order to reduce the costs of PHA for the production of biobased chemicals, the conversion of PHA to MC was tested using whole cells. In chapter 3, PHA rich cells were directly converted to MC using the optimised conditions found in chapter 2. The influence of fermentation salts, water and the presence of valerate monomers in the PHA were studied. It was found that the valerate monomers have no influence on the conversion. Fermentation salts do influence the conversion depending on the salt. Magnesium hydroxide catalyses the conversion of PHB to MC, where magnesium sulphate catalyses the formation of methyl 3-hydroxybutyrate as side product. The reaction tolerates up to 20% water, which means that the drying step in the downstream processing of PHA can be significantly reduced.

    The second step of the conversion of PHA to methyl acrylate and propylene involves an ethenolysis, a cross metathesis of MC with ethylene. This ethenolysis reaction requires a homogeneous catalyst. One of the most active catalysts for this conversion is the ruthenium based Hovey-Grubbs 2nd generation. However, the required high loading of this catalyst makes it an expensive part of the conversion. In order to enable reusing of the catalyst, immobilisation of the Hovey-Grubbs catalyst was investigated in chapter 4. The catalyst was immobilised inside a metal organic framework (MOF). For this purpose MIL-101-NH2(Al) was used for its large cavities connected by small openings. This allows the catalyst to reside inside the cavities, while the small openings prevent it from leaching out. The catalyst was successfully immobilised using a mechanochemical approach. This method can be applied on other catalysts as well, which was shown by the immobilisation of Zhan catalyst. Both immobilised catalysts show metathesis activity for multiple reaction cycles. It was found that the MOF, MIL-101-NH2(Al), partially undergoes a structural change to form MIL-53-NH2(Al). When MIL-53-NH2(Al) was used as starting MOF the catalyst was trapped but inactive. It was concluded that when starting from MIL-101-NH2(Al), the catalyst trapped in the parts of the material that was converted to MIL-53-NH2(Al) are catalytically inactive.

    To investigate the current state of the art of the use of ethenolysis on biomass, a literature review was performed in chapter 5. The results of the ethenolysis of methyl oleate (MO) were compared in order to investigate the most important parameters. It was found that the purity of the ethylene feed has the biggest influence on the turn over numbers (TONs) and that a higher purity ethylene has shown a larger impact on the ethenolysis of MO than the development of novel catalysts. When electron poor substrates are used, the highest TONs are obtained with the less stable Hoveyda-Grubbs 2nd generation. However, no studies were performed on the influence of ethylene purity on these reactions and higher TONs may be achieved using a higher purity ethylene.

    In chapter 6, the results and conclusions of the thesis are summarised. The implications of these findings are discussed and suggestions for further research within the field are given.

    Nanoscale force sensors to study supramolecular systems
    Cingil, E.H. - \ 2016
    Wageningen University. Promotor(en): Martien Cohen Stuart, co-promotor(en): Joris Sprakel. - Wageningen : Wageningen University - ISBN 9789462576971 - 136
    sensors - supramolecular chemistry - molecules - biopolymers - polymers - methodology - rheology - sensors - supramoleculaire chemie - moleculen - biopolymeren - polymeren - methodologie - reologie

    Supramolecular systems are solutions, suspensions or solids, formed by physical and non-covalent interactions. These weak and dynamic bonds drive molecular self-assembly in nature, leading to formation of complex ordered structures in high precision. Understanding self-assembly and co-assembly is crucial to unravel and mimic many processes occurring in nature. However, the challenge cannot be easily addressed especially in biological systems as it involves many dynamic interactions which may cooperatively, noncooperatively or competitively generate a complex manifold of interaction pathways. In this thesis, we employed two techniques to understand these complex interactions in various supramolecular systems at the nanoscale 1) multiple particle tracking microrheology to study thermoreversible assembly of triple helices in a collagen-inspired recombinant polypeptide in the form of a triblock copolymer gel former; and 2) polyfluorene-based conjugated polyelctrolyte mechosensors to monitor electrostatic co-assembly dynamics of (i) a recombinant diblock copolypeptide which encapsulates the conjugated polyelectrolyte like a protein capsid and (ii) various synthetic diblock copolymers which forms complex coacervate micelles; and finally the orthogonal self-assembly dynamics of (iii) a recombinant viral coat protein which mimics natural rod-like viruses. These novel polymeric mechanosensors work as versatile, non-invasive tools to detect even low degrees of analyte binding or complex formation due to the stress applied on their conjugated backbone. This mechanical stress causes the polymeric backbone to stretch which can be detected by a shift in its fluorescence spectra.

    Chemie - Van suiker naar mobiel : Kennisclip Bogo-project e-learning
    Baltissen, A.H.M.C. - \ 2016
    Groen Kennisnet
    biopolymeren - suiker - biobased economy - biochemie - chemische reacties - polymelkzuur - melkzuur - bioplastics - tuinbouw - lesmaterialen - biopolymers - sugar - biobased economy - biochemistry - chemical reactions - polylactic acid - lactic acid - bioplastics - horticulture - teaching materials
    Deze kennisclip maakt onderdeel uit van de lesmodule Biobased Economy van het CIV T&U.
    Boom geeft chemie nieuw leven
    Gosselink, Richard - \ 2014
    biopolymers - lignin - separation technology - wood - papermaking - energy saving - biobased chemistry - biobased economy
    Doodzonde om op te stoken. Lignine de grondstof van de toekomst
    Zundert, M. ; Gosselink, R.J.A. - \ 2014
    Chemie Magazine 2014 (2014)3. - ISSN 1572-2996 - p. 24 - 27.
    biopolymeren - lignine - toepassingen - bioraffinage - innovaties - chemie op basis van biologische grondstoffen - biobased economy - aromatische koolwaterstoffen - biopolymers - lignin - applications - biorefinery - innovations - biobased chemistry - biobased economy - aromatic hydrocarbons
    Onhandelbaar, wee barstig en recalcitrant. Zo staat het houtpolymeer lignine bekend. Maar de stof vervangt steeds vaker fenol. En onderzoekers zijn hoopvol over de ontwikkeling van bio-BTX en koolstofvezels uit lignine.
    Bioplastic op bestelling : grondstoffen kunnen steeds opnieuw worden geoogst
    Didde, R. ; Bolck, C.H. - \ 2014
    WageningenWorld (2014)4. - ISSN 2210-7908 - p. 10 - 15.
    bioplastics - materialen uit biologische grondstoffen - biobased economy - biopolymeren - markten - biodegradatie - prijsvorming - economische ontwikkeling - bioplastics - biobased materials - biobased economy - biopolymers - markets - biodegradation - price formation - economic development
    Bioplastics hebben de wind in de rug. Steeds meer bedrijven overwegen hun producten te maken van kunststoffen met een plantaardige oorsprong. Christiaan Bolck van Wageningen UR Food & Biobased Research helpt ze aan de juiste receptuur.
    Bioflocculation of wastewater organic matter at short retention times
    Faust, L. - \ 2014
    Wageningen University. Promotor(en): Huub Rijnaarts, co-promotor(en): Hardy Temmink. - Wageningen : Wageningen University - ISBN 9789462571716 - 153
    afvalwaterbehandeling - uitvlokking - bioreactoren - geactiveerd slib - organische verbindingen - biopolymeren - energieterugwinning - waste water treatment - flocculation - bioreactors - activated sludge - organic compounds - biopolymers - energy recovery
    Expositie brengt biobased economy tot leven
    Baltissen, A.H.M.C. ; Leeuwen, M.A.E. van; Dijk, W. van - \ 2014
    lesmaterialen - tentoonstellingen - biobased economy - materialen uit biologische grondstoffen - biopolymeren - voorlichting - onderwijs - teaching materials - exhibitions - biobased economy - biobased materials - biopolymers - extension - education
    Poster met informatie over de mobiele expositie 'Bio-Based'.
    Emerging technologies for biobased aromatics
    Haveren, Jacco van - \ 2014
    biobased chemicals - biobased chemistry - biobased economy - aromatic compounds - biorefinery - bioplastics - biopolymers - research
    The revival of microbial PHA polymers – are PHA’s back to stay?
    Bolck, Christiaan - \ 2014
    biopolymers - biobased materials - biobased economy - polyhydroxyalkanoates - bioplastics
    Understanding of the self- and co-assembly behavior of recombinant protein polymers : from design to implementation
    Golinska, M.D. - \ 2014
    Wageningen University. Promotor(en): Martien Cohen Stuart, co-promotor(en): Renko de Vries; Frits de Wolf. - Wageningen : Wageningen University - ISBN 9789461738134 - 165
    biopolymeren - eiwitten - zelf-assemblage - recombinant eiwitten - elastine - collageen - enzymatische cross-linking - glutaminase - biopolymers - proteins - self assembly - recombinant proteins - elastin - collagen - enzymatic cross-linking - glutaminase

    A key part of the growing field of biomedical sciences deals with the development of new, controlled and biocompatible biomaterials. In this thesis we present results on the design, production, purification and characterization of stimuli responsive protein polymers that could ultimately be used in that field. Protein-polymers are composed of two or three blocks that are able to self- and co-assemble. An important theme in the thesis is to highlight the specific advantages of our new protein polymer for future biomedical applications.

    We have used recombinant DNA techniques and expression in methylotrophic yeast Pichia pastorisfor protein production. DNAs encoding various polypeptide blocks were designed, produced using general molecular biology techniques and combined into synthetic genes for protein polymers. Synthetic genes were cloned into P. pastorisexpression vector pPIC9 that integrates into the yeast genome. Yields were high, typically reaching gram-per-liter (of medium).

    In Chapter 2we study dual-stimuli (pH, temperature) responsive silk-elastin-like protein polymers (SELPs). These polymers were designed to self- and co-assembly, controlled by both pH and temperature. The first protein is a diblock S24E40composed of 24 silk-like (S) repeats and 40 elastin-like (E) repeats. The other protein is a triblock S12C4E40, in which the Sand Eblocks are separated by a random coil block (C4) that serves as an inert ‘spacer’.

    A C2SHSHC2protein polymer, which consists of a pH responsive, positively charged silk-like middle block SH, flanked by two random coil collagen-like blocks C2was studied in Chapter 3.

    For this protein have studied fibril formation and gelling properties at pH values close to neutral, that are crucial for biomedical applications. We find that at physiological pH, these proteins form self-healing physical gels that fulfill many requirements for use in biomedical applications.

    In Chapter 4we test the influence of enzymatic cross-linking on elasticity andmechanical properties ofhydrogels that include collagen-like domains, using microbial transglutaminase (mTGase) as an enzymatic crosslinker that catalyzes the coupling of glutamines to lysines. We show that even though the collagen-like blocks are not particularly good substrates for the mTGase, the few cross-links that are made have a strong effect on the physical properties of the protein-polymer hydrogels. For silk-collagen fiber gels, the elastic moduli can be increased by a factor of five, and for thermosensitive collagen hydrogels, the enzymatic cross-linking induces qualitatively new behavior, namely shape-memory of hydrogels.

    Finally, we study the co-assembly of very asymmetric diblock copolymers with oppositely charged sodium poly(acrylic acid) (NaPAA) with a range of molar masses (Chapter 5). This asymmetric diblock consists of a cationic block of 12 lysines connected to a long (400 amino acid) collagen-like block with a net charge that is nearly zero. For shorter Na-PAA chains, spherical complex coacervates micelles are formed, as have been studied before in our lab. But, for long Na-PAA chains a new self-assembled structure is found: a single (Na-PAA) chain pearl-necklace of complex-coacervate micelles.

    The general discussion of the thesis in Chapter 6, focuses on recombinant and natural hydrogels as biomaterials. We point out the specific advantages of recombinant proteins and also indicate where these still need to be improved in order to be used in biomedical applications. Finally, we make some suggestions for further research in this area.

    BOGO van groene grondstoffen naar biobased materialen. eigenschappen van polymerlkzuur
    Schennink, G.G.J. ; Beukelaer, H.J. de; Molenveld, K. - \ 2013
    lesmaterialen - bioplastics - biopolymeren - polymelkzuur - beroepsopleiding (hoger) - materialen uit biologische grondstoffen - biobased economy - handleidingen - teaching materials - bioplastics - biopolymers - polylactic acid - professional education - biobased materials - biobased economy - guide books
    Deze opdracht geeft inzicht in de eigenschappen van PLA en daarmee de toepassingsmogelijkheden. Het praktijkdeel van deze opdracht laat zien hoe door keuze van de juiste PLA typen en temperatuurbehandeling de maximale gebruikstemperatuur (HDT=Heat Distortion Temperature) verhoogd kan worden.
    BOGO van groen grondstoffen naar biobased materialen. Van melkzuur naar polymeren.
    Knoop, J.R.I. - \ 2013
    Wageningen : FRB
    lesmaterialen - melkzuur - biopolymeren - polymelkzuur - polymerisatie - chemie - biobased economy - beroepsopleiding (hoger) - handleidingen - teaching materials - lactic acid - biopolymers - polylactic acid - polymerization - chemistry - biobased economy - professional education - guide books
    Lesmateriaal (theorie en praktijkopdracht) over de polymerisatie van melkzuur tot polymelkzuur (PLA).
    Check title to add to marked list
    << previous | next >>

    Show 20 50 100 records per page

    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.