Staff Publications

Staff Publications

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    '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.

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    Praktijkonderzoek bioraffinage
    Doorn, Wim van; Baars, J.J.P. ; Dam, J.E.G. van; Keijsers, E.R.P. ; Yilmaz, G. - \ 2018
    Amersfoort : Stichting Toegepast Onderzoek Waterbeheer (STOWA rapport 2018-25) - ISBN 9789057737930 - 59
    waterbeheer - bioraffinage - materialen uit biologische grondstoffen - biomassa - waterplanten - reststromen - water management - biorefinery - biobased materials - biomass - aquatic plants - residual streams
    Waterschappen en andere waterbeheerders zien dat de laatste jaren in toenemende mate inspanningen nodig zijn om problemen door uitheemse en/of invasieve plantensoorten in het waterbeheer te beheersen. Echte oplossingen zijn nog steeds niet beschikbaar. Tegelijkertijd werken de waterschappen samen met andere gebiedsbeheerders en ketenpartners aan verduurzaming van het waterbeheer, onder meer door bij te dragen aan een meer circulaire economie, en aan realisatie van de Kader Richtlijn Water doelstellingen. In dit project is onderzocht hoe bioraffinage kan bijdragen aan deze verduurzaming, door het produceren van diverse nuttige grondstoffen uit groenresten van het waterbeheer. Daarbij lag de nadruk op het verwaarden van woekerende waterplanten en oevermaaisels via kleinschalige, mobiele bioraffinage. Daarbij worden op de plaats ter waar maaisels vrijkomen via een bioraffinage machine de planten opgewerkt tot diverse producten, zoals eiwitten (voor diervoer of technische toepassingen), vezels (voor diervoeder, papier/karton of biocomposiet), mineralenconcentraat (meststof) en eventueel substraat voor vergisting tot biogas. Loosbaar water is wat overblijft en terug kan naar het aquatisch milieu.
    Literatuurstudie waarde halen uit groenresten in het waterbeheer
    Doorn, Wim van; Kooij, Aldert van der; Dam, Jan van - \ 2017
    Amersfoort : Stichting Toegepast Onderzoek Waterbeheer (Stowa rapport 2017-04) - ISBN 9789057737404 - 93
    reststromen - biobased economy - waterbeheer - bioraffinage - grasmaaisel - waterplanten - composieten - residual streams - biobased economy - water management - biorefinery - grass clippings - aquatic plants - composite materials
    Dit rapport beschrijft de resultaten van de verkennende literatuurstudie naar de mogelijkheden voor verwaarding via bioraffinage van vrijkomend maaisel en in het waterbeheer af te voeren waterplanten. Daartoe is een inventarisatie gemaakt van de vrijkomende hoeveelheden en samenstelling van maaisels bij de acht deelnemende waterschappen en is via een literatuurstudie informatie verzameld over de fysisch-chemische samenstelling van de meest voorkomende planten in de maaisels. Daarbij is een literatuurscan uitgevoerd van de wetenschappelijke literatuur naar wat bekend is over biomassa samenstelling van de meest voorkomende niet-inheemse waterplanten en de aanwezigheid van specifieke inhoudstoffen voor verwaarding. Op basis van deze informatie en inzicht in biobased conversie technieken, is een inschatting gemaakt van het potentieel voor verwaarding van deze groenresten door waterschappen. Mogelijke producten zijn eiwitten voor veevoeder of technische toepassingen, vezels voor papier/karton of diverse biocomposiet-toepassingen, en soms zijn specifieke inhoudstoffen aanwezig, zoals gelerende stoffen of antioxidantia.
    Sugar beet leaves: from biorefinery to techno-functionality
    Kiskini, Alexandra - \ 2017
    Wageningen University. Promotor(en): H. Gruppen, co-promotor(en): P.A. Wierenga. - Wageningen : Wageningen University - ISBN 9789463436793 - 141
    sugarbeet - sugarbeet tops - biorefinery - bioprocess engineering - proteins - isolation techniques - physiological age - suikerbieten - suikerbietenloof - bioraffinage - bioproceskunde - eiwitten - isolatietechnieken - fysiologische leeftijd

    Sugar beet leaves (SBL), which are a side stream of the sugar beets cultivation, are currently left unexploited after sugar beets have been harvested. The general aim of this thesis was to study the biorefinery of SBL, with a special focus on the isolation of proteins. To reach this aim the research was divided into three sub-aims: 1) to determine whether there is variability in the chemical composition of the leaves due to pre-harvest conditions (plant age), 2) to evaluate the variability of the techno-functionality of leaf soluble protein concentrate (LSPC) due to system conditions and 3) to extend current product and process synthesis approaches to enable the design of biorefining process. To address the first aim, SBL collected at different time points were used. Despite a small variation in the chemical composition of the leaves of different plant ages, a large effect of the plant age on the quality of LSPC was observed. In particular, LSPC from old plants was brown (indicative of polyphenol oxidase - PPO - activity), whereas LSPC from young plants was yellow. Based on these data, samples extracted with sodium disulfite (to inhibit PPO-mediated browning) were used for further experiments. The obtained LSPC consisted mainly of protein (69.3% w/w db (N∙5.23)) and carbohydrates (5.1% w/w db; half of which was charged carbohydrates). The main protein present in LSPC was Rubisco. The emulsion and foam properties of LSPC were studied as a function of protein concentration (Cp), pH and ionic strength (I). The minimal Cp of LSPC needed to form a stable emulsion (Ccr) was comparable to that of other widely used plant proteins, such as soy protein isolate. A critical ζ-potential (ζcr ~ 11 mV) was identified, below which flocculation occurs. At pH 8.0 and high I (0.5 M) the Ccr was higher than at low I (0.01 M), which relates to a higher protein adsorbed amount at the interface (Γmax). The foam ability (FA) of LSPC increased with Cp at all conditions tested. The FA was related to the soluble and not to the total Cp in the bulk. Interestingly, the minimal Cp; i.e.CcrFA needed to reach highest FA was constant as a function of pH. At high I (0.5 M) LSPC had higher FA than at low I (0.01 M), which was related to the faster adsorption of proteins at the interface. A minimum Cp was required to form stable foams. At pH 3.0 and 5.0 the foam stability of LSPC was higher than at pH 8.0. This was postulated to be due to formation of aggregates (between proteins or between proteins and charged carbohydrates). From these data it was shown that the techno-functional properties of LSPC could be linked to the molecular and interfacial properties of the dominant proteins in the concentrates. Thus, predictions for the techno-functional properties of impure systems, such as LSPC, can be made using only the known molecular properties of the dominant proteins and a small set of experiments. The knowledge acquired through the previous studies was used to adapt an existing methodology; namely the product-driven-process synthesis (PDPS) methodology, to extend its use in biorefinery. The adapted PDPS contained 4 novel steps, which facilitated its use in biorefinery. To illustrate how this new approach can be used in practice, a case study of a sugar beet leaves biorefinery was presented.

    Harvesting and cell disruption of microalgae
    Lam, Gerard Pieter 't - \ 2017
    Wageningen University. Promotor(en): R.H. Wijffels; M.H.M. Eppink, co-promotor(en): M.H. Vermuë. - Wageningen : Wageningen University - ISBN 9789463431736 - 206
    algae - harvesting - flocculation - polymers - chlorella vulgaris - biorefinery - electric field - organelles - algen - oogsten - uitvlokking - polymeren - chlorella vulgaris - bioraffinage - elektrisch veld - organellen

    Microalgae are a potential feedstock for various products. At the moment, they are already used as feedstock for high-valuable products (e.g. aquaculture and pigments).

    Microalgae pre-dominantly consist out of proteins, lipids and carbohydrates. This makes algae an interesting feedstock for various bulk-commodities. To successfully produce bulk-commodities, a multi-product biorefinery should be adopted that aims on production of both bulk- and high value co-products. In the downstream process, however, harvesting- and cell disruption are technological hurdles for cost effective multi-product biorefinery.

    Flocculation is considered as a low-cost harvesting process. Flocculating microalgae at high salinities used to be not feasible We demonstrated that marine microalgae can successfully be flocculated and harvested by using cationic polymers.

    In the second part of this thesis we studied Pulsed Electric Field (PEF) as potential cheap and non-disruptive technology to open microalgae. PEF-treatment evokes openings/’holes’ in micro-organisms. PEF in combination with a pre-treatment to weaken the cell wall resulted in release of proteins from microalgae at low energy consumption.

    Recent advances in technology development learned that harvesting of micro-algae is no longer a bottleneck. Future research and development should focus on cell disruption and mild extraction technologies. Costs for the biorefinery will decrease by process simplification. For that unit operations for cell disruption and extraction need to be integrated.

    This project was part of a large public private partnership program AlgaePARC biorefinery ( Objective of this program is to develop a more sustainable and economically feasible microalgae production process. For that all biomass components (e.g. proteins, lipids, carbohydrates) should be used at minimal energy requirements and minimal costs while keeping the functionality of the different biomass components. Biorefining of microalgae is very important for the selective separation and use of the different functional biomass components.

    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.
    Lignine : groene grondstof voor chemicaliën en materialen
    Dam, Jan van; Harmsen, Paulien ; Bos, Harriëtte ; Gosselink, Richard - \ 2016
    Wageningen : Wageningen Food & Biobased Research (Groene grondstoffen ) - ISBN 9789463430197 - 54
    lignine - chemicaliën uit biologische grondstoffen - biobased economy - toepassingen - bioraffinage - productieprocessen - lignin - biobased chemicals - biobased economy - applications - biorefinery - production processes
    De mogelijkheden voor het gebruik van lignine worden in dit boekje toegelicht. Deze uitgave heeft als doel meer informatie te geven over de eigenschappen van lignine en de vele mogelijkheden die lignine biedt als grondstof voor chemicaliën en materialen voor de biobased economy.
    SPARK-UP; Seaweed Production And Refining of Kelp, Ulva and Palmaria : 2013-2016
    Wald, J. ; Visser, W. de; Brandenburg, W.A. ; Jongschaap, R.E.E. ; Werf, A.K. van der; Deelman, Berth-Jan ; Helmendach-Nieuwenhuize, Carola - \ 2016
    Plant Research International - 144
    seaweeds - biobased economy - seaweed culture - biomass production - biomass conversion - aquatic biomass - biorefinery - seaweed products - applications - applied research - cropping systems - marketing channels - zeewieren - biobased economy - zeewierenteelt - biomassa productie - biomassaconversie - aquatische biomassa - bioraffinage - zeewierproducten - toepassingen - toegepast onderzoek - teeltsystemen - marketingkanalen
    In het SPARK-UP project, waarin de partners Arkema, PRI-WUR en North Seaweed samenwerkten aan de ontwikkeling van toepassing van zeewier in de biobased economy, is de afgelopen jaren veel werk verzet. In een bassin op het terrein van Arkema, heeft PRI een teeltsysteem opgezet en in gebruik genomen, om onder gecontroleerde omstandigheden zeewier te telen in Westerscheldewater dat in het bassin was ingenomen. Arkema heeft gewerkt aan de raffinage van wieren, met name gericht op de suikers. North Seaweed heeft zich geconcentreerd op het ontwikkelen van businesscases van geraffineerde eiwitten en alginaten uit zeewier en bij het gebruik van de hele wieren als plantversterkers.
    The assessment of advanced pre-treatment chains. TO2 Advanced pre-treatment of biomass; Task A3
    Meesters, K.P.H. ; Annevelink, E. ; Keijsers, E.R.P. - \ 2016
    Wageningen UR - Food & Biobased Research - ISBN 9789462577213 - 23
    value chain analysis - supply chain management - biomass - biobased materials - biobased economy - bioenergy - biorefinery - modeling - pretreatment - waardeketenanalyse - ketenmanagement - biomassa - materialen uit biologische grondstoffen - biobased economy - bio-energie - bioraffinage - modelleren - voorbehandeling
    The overall objective of the TO2 project ‘Advanced pre-treatment of biomass’ was to design optimal energy-driven refinery chains for the susta inable valorization of non-woody biomass to biobased commodities. Therefore optimal combination s need to be found of upstream biorefining and the production of high-quality (sol id) energy carriers from a broad spectrum of non-woody biomass streams. Task A3. within this TO2 project focused on modelling chains and performing an economic evaluation of these chains. Three cases of biomass chains were modelled and evaluated in this report.
    Small-scale Biorefining
    Visser, C.L.M. de; Ree, R. van - \ 2016
    Wageningen : Wageningen University & Research - 62
    biorefinery - biobased economy - resource utilization - biomass conversion - techniques - residual streams - economies of scale - case studies - bioraffinage - biobased economy - hulpbronnengebruik - biomassaconversie - technieken - reststromen - schaalvoordelen - gevalsanalyse
    One promising way to accelerate the market implementation of integrated biorefineries is to promote small (regional) biorefinery initiatives. Small-scale biorefineries require relatively low initial investments, and therefore are often lacking the financing problems that larger facilities face. They are potentially able to make use of available local resources and involve stakeholders and product markets that create a common foundation for joint development and market deployment. Furthermore, by using modular and transportable units, the refinery process potentially can be operated at several locations, increasing their operation window, and therefore their market competitiveness. Small-scale biorefinery processes seem to be specifically interesting for the efficient and sustainable valorisation for relatively wet agro-crops (grass, beets, maize, etc.), agro-residues (leaves/foliage), food processing residues and aquatic biomass (microalgae, duckweed, etc.).
    Mild disintegration of green microalgae and macroalgae
    Postma, Richard - \ 2016
    Wageningen University. Promotor(en): Michel Eppink; Rene Wijffels, co-promotor(en): Giuseppe Olivieri. - Wageningen : Wageningen University - ISBN 9789462579477 - 181
    algae - chlorella vulgaris - bioprocess engineering - biorefinery - proteins - milling - carbohydrates - biobased economy - disintegrators - technology - extraction - algen - chlorella vulgaris - bioproceskunde - bioraffinage - eiwitten - maling - koolhydraten - biobased economy - desintegrators - technologie - extractie

    An increased worldwide protein demand for food and feed and the necessity to release the water soluble proteins in the first stage of the cascade biorefinery require the development of mild protein extraction technologies. Cell disintegration is the first hurdle and is considered as one of the most energy consuming steps. Therefore, this thesis focused on the development of a mild, scalable and energy efficient disintegration technology for green microalgae and macroalgae (seaweed) aimed on extraction of water soluble components (like proteins and carbohydrates).

    For microalgae disintegration, two main technologies were investigated. First of all the conventional technology bead milling and second a novel approach using Pulsed Electric Field (PEF). In Chapter 2 a benchmark was set by means of bead milling for the release of water soluble protein from the green microalgae Chlorella vulgaris. Overall, protein yields between 32 and 42% were achieved, while the energy consumption was reduced with 85% by selective protein extraction to values as low as 0.81 kWh kgDW-1. Remarkably, the benchmark was much better than expected.

    In Chapter 3 the bead mill was further optimized by decreasing the applied bead size, furthermore the applicability of bead milling on two additional microalgae species (Neochloris oleoabundans, Tetraselmis suecica) was shown. In addition, to be able to better understand the disintegration mechanism, the so-called stress model was applied. This model describes the comminution process in a bead mill as function of the amount of bead contacts and the force of each impact. The release kinetics could be improved and thereby the specific energy consumption could be reduced to 0.45‒0.47 kWh kgDW-1 by using 0.3 mm beads for all algae.

    Chapter 4 describes a screening on the applicability of PEF, over a broad range of operating conditions, for the extraction of water soluble proteins from the microalgae C. vulgaris and N. oleoabundans. No substantial protein yields were observed under the investigated conditions. This led to the conclusion that PEF is not suitable to release water soluble proteins, not even at specific energy consumptions much higher than those for the benchmark, bead milling.

    In Chapter 5 it was attempted to improve the performance of PEF by investigating the synergistic effect with the processing temperature. The PEF experiments were performed using a pilot scale continuous flow electroporation unit in which the processing temperature was controlled between 25 – 65 °C. The results showed that under the tested conditions, the combined PEF-Temperature treatment did not cause substantial disintegration of the algal cells to effectively release water soluble proteins.

    In addition to the microalgae, macroalgae were subject of investigation in the search for new protein sources in Chapter 6. Four batch technologies were used to disintegrate the green macroalgae Ulva lactuca, being; osmotic shock, enzyme incubation, PEF and High Shear Homogenization (HSH). In descending order the highest protein yields per treatment; HSH (~40%) > enzyme degradation (~25%) > osmotic shock (~20%) > PEF (~15%).

    In the final chapter the main results and remaining bottlenecks are discussed and a future outlook on microalgae disintegration is presented. To date, bead milling is the only technology able to disintegrate fresh microalgae at specific energy consumptions below 10% of the total energy available from the algae and release substantial amounts of water soluble protein. The future outlook was based on a techno-economic evaluation, which showed that the cultivation costs are limiting the economic feasibility of microalgae biorefinery. Future focus should be on the cultivation.

    Geraffineerd voeren : naar een sluitende mineralenkringloop door raffinage van lokaalgeteeld veevoer
    Sanders, J.P.M. ; Liere, J. ; Wilt, J.J. de - \ 2016
    Utrecht : Innovatie Agro & Natuur - Netwerkorganisatie voor grensverleggende vernieuwingen - ISBN 9789050595278 - 32
    veevoeding - melkveevoeding - varkensvoeding - bioraffinage - grasmaaisel - maïs - mineralenboekhouding - livestock feeding - dairy cattle nutrition - pig feeding - biorefinery - grass clippings - maize - nutrient accounting system
    Raffinage van in Nederland geteeld voer kan bijdragen aan het verminderen van de import van voer en daarmee van de nutriënten fosfor en stikstof. Die verminderde import aan nutriënten is het gevolg van het verbeteren van de voerbenutting van de geraffineerde producten en dan met name van in gras en snijmais aanwezige eiwitten. De import van eiwit is immers de belangrijkste bron van onze fosfor- en stikstofoverschotten. In deze rapportage worden het raffinage proces beschreven, alsmede de stromen die bij de verschillende bewerkingen vrijkomen. De mogelijkheden voor inzet van deze stromen als voer voor runderen dan wel varkens passeren de revue. Tevens wordt een globale kosten- en opbrengstenberekening gemaakt. Tenslotte volgt een schets van de implicaties van de verschuivingen in eiwitbenutting op nationaal niveau. Zijdelings wordt aandacht besteed aan de productie van eendenkroos als eiwitbron.
    Biorefinery of leafy biomass using green tea residue as a model material
    Zhang, C. - \ 2016
    Wageningen University. Promotor(en): Johan Sanders, co-promotor(en): Marieke Bruins. - Wageningen : Wageningen University - ISBN 9789462576902 - 156
    biorefinery - biomass conversion - leaves - biomass - green tea - tea - alkaline pulping - pectins - lignocellulose - environmental impact - processes - plant protein - food - biobased economy - bioraffinage - biomassaconversie - bladeren - biomassa - groene thee - thee - alkalische pulpbereiding - pectinen - lignocellulose - milieueffect - processen - plantaardig eiwit - voedsel - biobased economy


    With the rapidly growing world population and improving living standards, food demand is increased with a simultaneous desire for less human impact on the environment, such that “Twice the food production at half the ecological footprint” could be the EU goal for 2050. In fact, a boost in food demand is mainly required in developing countries, where the farmlands are limited and/or they are of poor quality. Rather than improving crop-production yield, developing biorefinery technology with unused biomass, such as leaves, in developing countries may be the key to fulfil the food demand.

    Four major components, protein, pectin, lignin, and (hemi-) cellulose, account for more than 70% of the materials in leaves in almost all species. Among these components, protein and pectin can be used in food and animal feed, and they are key components for supplementing food production. However, the production and application of leaf products is limited for four reasons: unstable raw materials, complex components, rigid plant cell walls, and underdeveloped leaf logistics and economics. The limitations cause low pectin and protein yields, and low cost-efficiency in current extraction technologies, including mechanical milling, chemical extraction (acid and alkaline), solvent extraction, and ammonia protein extraction. Development of an integrated process for multiple products might be a good option for leaf biorefinery, but the compatibilities of these processes were unknown.

    The aim of this study was to develop new processes and applications that optimally utilize all components, particularly protein, of leafy biomass in the feed and/or food industry using green tea residues as a starting material. The method should also be applicable to other leafy biomass. The research started from the development of alkaline protein extraction technology as presented in Chapter 2. We found that in alkaline protein extraction, temperature, NaOH amount, and extraction time are the parameters determining protein yield, while pH and volume of extraction liquid are critical parameters for production cost. After optimization, more than 90% of leaf protein could be extracted at a cost of 102€/ton protein by single step alkaline extraction. The extracted protein nutritional value was comparable to soybean meal and this technique can be adapted to various leafy biomass. Main drawback of this technique is the overuse of alkali, generation of salts, and the destruction of key amino acids, such as lysine, during the extraction. We tried to overcome its drawbacks by developing integrated process with a recycle for chemicals.

    Chapter 3, 4, 5, and 6 refer to the integrated biorefinery. For a better design, we investigated how the alkali aided protein extraction (Chapter 3), and proved that alkaline protein extraction was not facilitated by increased solubility or hydrolysis of protein, but positively correlated to leaf tissue disruption. HG pectin, RGII pectin, polyphenols, and organic acids can be extracted before protein. Protein extraction can then be followed by the extraction of cellulose and hemi-cellulose. RGI pectin and lignin yield were both linearly correlated to protein yield, which indicated that they are likely to be the key limitation to leaf protein extraction. Based on the above findings, an integrated biorefinery that combined protein extraction with a pre-treatment was proposed. In Chapter 4, ethanol, viscozyme, and H2O2 were selected for pre-treatments targeting on the removal of polyphenols and pigments, carbohydrates, and lignin accordingly. Ethanol and viscozyme could extract their targeting components efficiently while H2O2 could bleach GTR with no lignin extracted. The best pre-treatment was the combination of viscozyme and 50% ethanol extraction, which not only reduced the use of alkali by 50%, but also improved protein content and its nutritional value. As pectin can be applied for food or chemicals, enzyme and PBS buffer were investigated for pectin extraction (Chapter 5). Both enzyme and PBS buffer extraction could not only extract high yield HG pectin (predominated by galacturonic acid) with no protein extraction, but also reduced alkali usage in subsequent protein extraction. Pectin obtained using PBS buffer could be present in its native form, which can be precipitated by 40% ethanol. Buffer is suggested to extract pectins when pectins are to be used in food. Otherwise, hydrolyzed pectin that mainly contains galacturonic acid, can be converted to other useful chemicals. For this the enzymatic methods, such as using Viscozyme® L, are recommended.

    Alkali usage was further optimized. It was found that by using potassium hydroxide, the protein extraction efficiency was similar to that using sodium hydroxide. The waste water, mainly containing potassium salts, can then be used as fertilizer. This technique is highly depending on the location of factories, which should be built close to the field. Alternatively, calcium hydroxide can be used. As calcium salts can be precipitated by CO2 and calcium hydroxide can be regenerated through burning of the precipitate, this scheme is sustainable and adaptable to most situations. However, as calcium also precipitated pectin, ployphenols, and even proteins, the protein yield is relatively low. Although a pre-treatment can improve extraction efficiency of calcium hydroxide, economic results suggested that a pre-treatment is not necessary unless the products obtained by pre-treatment have an attractive market value.

    In Chapter 7, we extend our knowledge on leaf biorefinery with some additional experiments and literature. Simplified models of leaf tissues and cell walls were proposed and used to explain the mechanism of alkaline protein extraction. The models were also used to explain other mechanisms for protein extraction; mechanical milling, steam explosion, acid, and enzyme aided extraction. The possible improvements of leaf biorefinery economics were illustrated either by reducing production cost, by e.g. using counter current extraction or ultrafiltration, or by upgrading product value by applying protein and pectin in food. The processes recommended in this thesis show an excellent prospective, in which they are applicable to other leaf biomass and suitable for small-scale production.

    Biorefinery of proteins from rubber plantation residues
    Widyarani, R. - \ 2016
    Wageningen University. Promotor(en): Johan Sanders, co-promotor(en): Marieke Bruins; E. Ratnaningsih. - Wageningen : Wageningen University - ISBN 9789462576643 - 236
    biorefinery - biomass conversion - rubber - rubber plants - protein extraction - latex - hydrolysis - hydrophobicity - amino acids - wheat gluten - residual streams - biobased economy - bioraffinage - biomassaconversie - rubber - rubberplanten - eiwitextractie - latex - hydrolyse - hydrofobiciteit - aminozuren - tarwegluten - reststromen - biobased economy

    Biorefinery of rubber tree side streams could add economic value and income for farmers, who already grow the trees for latex production. The objective of this research was to design a process for the recovery of proteinaceous fractions from rubber tree. The aimed applications were expected to be suitable for local use, particularly in Indonesia, being one of the world’s largest rubber producers. Rubber seed was selected as a model biomass based on its availability (21-144 kg-protein/ha) and its oil content that enables the combination of protein and biodiesel productions within a biorefinery framework. Experimental works were focused on three parts: separation of protein and oil from rubber seed kernel, enzymatic hydrolysis of rubber seed protein into amino acids, and separation of amino acids from hydrolysate. Using alkaline extraction, up to 80% protein from the total original amount of protein in the kernel could be recovered in the extract, comparable to protein recoveries from other oilseeds and oilseed cakes. Seed type and pre-treatment had the most influence on protein recovery. Following protein extraction, the extracted proteins were recovered via isoelectric precipitation, resulting in rubber seed protein concentrate that can be used as such or can be processed further. Different protease combinations were used to hydrolyse rubber seed protein concentrate. After 24 h hydrolysis of rubber seed protein, up to 53% degree of hydrolysis and 35% protein recovery as free amino acids could be achieved. Combination of Pronase + Peptidase R resulted in the highest recovery and concentration of hydrophobic amino acids (phenylalanine, leucine, isoleucine, tyrosine, tryptophan, valine, methionine, and proline) in the hydrolysate. Some hydrophobic amino acids are essential in human and farm animal diets, therefore they can potentially be applied as a group in food and feed. Ethanol was used as an anti-solvent for selective precipitation of amino acids. Ethanol was able to selectively increase the hydrophobic amino acid fraction in rubber seed protein hydrolysate from 59% (mol/mol) in the starting material to 76% in the supernatant. Leucine and valine contributed most to this increase. The results of this study show that rubber seed proteins can be applied locally as animal feed or in industries for technical applications.

    Extraction of steviol glycosides from fresh Stevia using acidified water; clarification followed by ultrafiltration and nanofiltration
    Kootstra, A.M.J. ; Elissen, H.J.H. ; Huurman, Sander - \ 2016
    Lelystad : Wageningen UR, PPO/Acrres (Rapport / PPO-AGV 686) - 38
    separation technology - stevia - purification - biorefinery - glycosides - ultrafiltration - filtration - scheidingstechnologie - stevia - zuiveren - bioraffinage - glycosiden - ultrafiltratie - filtratie
    As part of the PPS Kleinschalige bioraffinage project (WP1b), fresh Stevia material was used in the extraction of steviol glycosides using water acidified through conversion of sugar by microorganisms naturally present on the plant. Two successive harvests from the same plot were used. Previous experiments had resulted in high steviol glycoside extraction rates of 80 % to 90 % but the purity of the final extract was low (15 % to 20 % of steviol glycosides in the dry matter). The first batch of plants was used to test a clarification step by filtration on a small scale. A second batch of plants was used to perform clarification, purification using ultrafiltration, and concentration by nanofiltration on a larger scale.
    Biorefinery : recovery of valuable biomolecules
    Eppink, M.H.M. - \ 2015
    Wageningen : Wageningen University - ISBN 9789462573789 - 28
    biorefinery - recovery - biomass - biofuels - separation technology - biomass conversion - biomass cascading - biobased economy - bioraffinage - terugwinning - biomassa - biobrandstoffen - scheidingstechnologie - biomassaconversie - biomassa cascadering - biobased economy
    Inaugural speech Wageningen University, 23 April 2015
    Grasraffinage en gebruik van grasvezel in de rundveevoeding
    Klop, A. ; Durksz, D.L. ; Zonderland, A. ; Koopmans, B. - \ 2015
    Wageningen : Wageningen UR, Livestock Research (Livestock Research rapport 790) - 26
    veevoeding - melkveevoeding - kalvervoeding - bioraffinage - grasmaaisel - vezels - eiwit - proeven - melkveehouderij - livestock feeding - dairy cattle nutrition - calf feeding - biorefinery - grass clippings - fibres - protein - trials - dairy farming
    In 2012 is een proef met melkkoeien uitgevoerd met als doel de waarde van grasvezel te onderzoeken. In het rantsoen van de koeien werd een deel van de graskuil vervangen door grasvezel. De grasvezel kwam beschikbaar na de raffinage van gras. De resultaten van de proef vielen tegen. De voeropname van de koeien die grasvezel kregen was namelijk lager dan van de (controle)koeien die het gangbare rantsoen kregen. De melkgift was eveneens lager op het rantsoen met grasvezel. De oorzaak van de lagere voeropname heeft waarschijnlijk te maken met de versheid en daarmee de smakelijkheid van grasvezel. Daarom is in 2013 besloten om eerst te kijken naar de mogelijkheid om grasvezel te conserveren (in te kuilen), waardoor de kwaliteit en de houdbaarheid mogelijk werd verbeterd. In 2012 is eveneens een oriënterend onderzoek gedaan met graseiwit verstrekt aan kalveren. Graseiwit is het eiwit dat gewonnen wordt uit het grassap en in de proef werd het in gelvorm verstrekt. De resultaten van de proef met kalveren waren uitermate positief. De dieren namen het graseiwit graag op. De groei van de kalveren was vergelijkbaar met de controlegroep.
    Ketenanalyse en productverkenning voor valorisatie pelagische bijvangst en bijproducten
    Broeze, J. ; Poelman, M. ; Kals, J. ; Rurangwa, E. ; Vogel-van den Bosch, H.M. de - \ 2015
    Wageningen : Wageningen UR - Food & Biobased Research - ISBN 9789462577091 - 27
    bijvangst - reststromen - bioraffinage - vis - hydrolyse - veevoeder
    Dit rapport presenteert een analyse naar alternatieve mogelijkheden voor verwaarding van visbijvangst ten opzichte van vismeel.

    Het hier gerapporteerde onderzoek omvat een brede inventarisatie van mogelijkheden binnen de wettelijke kaders. Door middel van een expert-brainstorm en een inventarisatie van recente productinnovaties in de markt zijn de volgende ideeën gegenereerd:
    A. afzet van beschadigde vis voor bewerkte voedseltoepassingen;
    B. verwerking van huiden tot leder;
    C. geur- en smaakstoffen op basis van vis-eiwitten; ook attractanten t.b.v. visvoer;
    D. bioactieve peptiden (met gezondheidsbevorderende eigenschappen), te produceren door middel van (enzymatische of evt. zure) hydrolyse;
    E. vis-eiwit als allergeen-vrij (afgezien van parvalbumin) alternatief voor koemelk en sojamelk (denk aan babyvoeding);
    F. collageen voor bijvoorbeeld voeding, cosmetica of technische toepassingen;
    G. fosfolipiden voor emulsies (zoals margarine);
    H. visolie in voeding; geur en smaak kunnen gemaskeerd worden;
    I. mineralen-vitamines-supplementen uit vis, o.a. selenium, vitamines a, d en e;
    J. silage (auto-hydrolyse), waarbij de vissilage verder kan worden gescheiden in:
    o eiwitten voor diervoeder (bijvoorbeeld nat voor varkens; droog voor pluimvee);
    o olie scheiden/zuiveren.
    Vanuit de sector zelf is idee (A) in de praktijk gebracht: beschadigde vis wordt succesvol in de bestaande markt afgezet. Dit idee is mede daarom in het project niet verder uitgewerkt.
    Door het projectteam en vertegenwoordigers uit de pelagische sector zijn uit bovenstaande lijst drie opties geselecteerd voor verdere analyse:
    1. Silage gericht op grondstof voor diervoeders (optie J).
    2. Silage met winning van bioactieve peptiden (combinatie van opties D en J)
    3. Milde hydrolyse gericht op winning van bio-actieve peptiden (optie D).

    Het eerste opties betreft silage: onder toevoeging van zuur worden eiwitmoleculen opgeknipt tot onder andere peptiden en aminozuren. Het silage-product kan worden afgezet als veevoeder, bijvoorbeeld als alternatief voor sojameel. Helaas levert deze business case een negatief resultaat.

    Bij de tweede optie, hydrolyse, worden eiwitketens ook opgeknipt in kleinere stukken, vooral peptiden. Maar hierbij wordt het proces beter gecontroleerd, zodat relatief grote hoeveelheden waardevolle specifieke peptide-moleculen worden gevormd. Hydrolyse kan ook worden uitgevoerd door toevoeging van zuur, maar dan bij gecontroleerde temperatuur en procestijd (het proces wordt gestopt door neutralisatie). Het meest doelgericht kunnen specifieke peptiden worden gevormd door gebruik van enzymen in plaats van zuur.
    Hydrolysaten kunnen worden afgezet als voedselingrediënt (bijvoorbeeld met aangepaste technische eigenschappen), als gezondheidsbevorderend bio-actieve component (in voeding of als voedingssupplement) of voor diervoerdertoepassingen.
    Hoewel wetgeving dat niet expliciet voorschrijft, wordt in dit rapport geconcludeerd dat voor humane consumptie de vis voor het hydrolyseproces moet worden gestript. Dit drijft de prijs voor het ingangsmateriaal aanzienlijk op.
    Uit kosten-batenanalyses van zowel de veevoeder-optie als voor humane toepassingen volgt een positieve business case. Maar deze positieve uitkomsten zijn wel sterk afhankelijk van prijzen van zowel het ingangsmateriaal als de eindproducten. Omdat ontwikkeling van deze opties op basis van vis in de kinderschoenen staat, is amper informatie over afzetprijzen beschikbaar is. Omdat deze prijzen kritisch zijn voor een positieve business case, wordt aangeraden bij een eventuele vervolgontwikkeling ook mogelijke afnemers te betrekken.

    Als laatste idee is nog gekeken naar een mogelijke tussenvorm tussen silage en hydrolyse: bioactieve moleculen uit silage. Helaas blijkt dat zelfs bij minimale hoeveelheid zuur (ondergrens wordt bepaald door eisen voor houdbaarheid) het product na enkele maanden bewaring te ver gehydrolyseerd is (meeste bio-actieve peptiden zijn afgebroken tot aminozuren). Dus, alleen door een beperkte (vooral qua tijd) hydrolysestap kan nog een product met bio-actieve waarde worden geproduceerd.

    Geconcludeerd wordt dat milde hydrolyse het beste perspectief beidt. Toepassing voor zowel voedsel als diervoeders is mogelijk. Echter, voor voedingstoepassingen heeft bijvangst een nadeel ten opzichte van bijproduct van visverwerking omdat de vis gestript moet worden. Diervoedertoepassing past daarom beter.
    Voor zowel voedings- als diervoedertoepassing zal ook de markt nog ontwikkeld moeten worden.
    Efficiënter gebruik van voedermiddelen en (geïmporteerde) diervoedergrondstoffen : mogelijkheden als grondstoffenbron voor de Biobased Economy
    Kasper, G.J. ; Duinkerken, G. van; Krimpen, M.M. van; Wagenberg, C.P.A. van; Kals, J. ; Sanders, J.P.M. ; Visser, C.L.M. de - \ 2015
    Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 946) - 63
    voedertechnologie - voedermiddelbewerking - voer - biomassa - biomassa cascadering - bioraffinage - biobased economy - nederland - haalbaarheidsstudies - gevalsanalyse - feed technology - feed processing - feeds - biomass - biomass cascading - biorefinery - biobased economy - netherlands - feasibility studies - case studies
    In this study it was estimated that 6.4 out of 35.0 million tons (dry matter) of animal feeds and raw feed materials that are annually available in the Netherlands, can be used as a resource for application in the biobased economy. Biorefinery enables us to extract feed components that cannot be utilized by animals. The challenge is to add value by applying these components in various value chains (cascading).
    Mest vol verwaarden? Wat kan raffinage betekenen?
    Starmans, D.A.J. ; Buisonjé, F.E. de; Dijk, W. van; Haan, J.J. de; Timmerman, M. ; Visser, C.L.M. de - \ 2015
    Lelystad : WUR/ACRRES (Rappot / PPO-AGV 658) - 41
    mestverwerking - samenstelling - bioraffinage - economische haalbaarheid - haalbaarheidsstudies - terugwinning - materialen uit biologische grondstoffen - manure treatment - composition - biorefinery - economic viability - feasibility studies - recovery - biobased materials
    Het doel van deze studie was te inventariseren welke waardevolle stoffen uit mest gewonnen kunnen worden en wat de potentie is in technologie en markt om deze te verwaarden. De inhoud van mest kan onderverdeeld worden in de volgende hoofdcategorieën: organische stof, mineralen, zware metalen, aminozuren, vluchtige vetzuren, antibiotica, hormonen. Via literatuuronderzoek is de samenstelling van elke categorie uiteen gesplitst in de verschillende stoffen met daarbij het gemiddelde gehalte van de betreffende stof in mest. Voor elke stof is de range in marktprijs nagegaan en aan de hand van het gehalte en marktprijs is de intrinsieke waarde van elke stof in de mest bepaald. Per hoofdcategorie van stoffen valt aan de hand van de waarde van de componenten te voorspellen of het mogelijk is om een sluitende business case te maken.
    Biorefinery: refining tomorrow
    Eppink, M.H.M. - \ 2015
    Wageningen UR
    bioraffinage - biomassaconversie - biobased economy - scheidingstechnologie - onderzoek - onderzoeksinstituten - biorefinery - biomass conversion - biobased economy - separation technology - research - research institutes
    Wageningen UR is one of the world's leading institutes in Circular Biobased Economy R&D. We see biorefinery as the key enabler of this sustainable, future economy. Wageningen UR offers a toolbox full of technologies and expertise for biorefinery. Technologies related to pretreatment, (mild) separation and chemical- or bioconversion. And expertise related to designing sustainable biorefinery value chains.
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