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Evaluatiebijeenkomst Hanzehogeschool Groningen

Inspiratiesessie Gasterra

In samenwerking met M. Theelen en B. van der Velde van Gasunie is de Groningse startbijeenkomst gehouden voor Check je warmtelek. Centraal stond het verloop van het onderzoek/project en bijzondere meetvoorbeelden.

Het RIVM heeft verkennend onderzocht welke informatie in openbare literatuur beschikbaar is over de samenstelling van isolatiematerialen en welke stoffen eruit kunnen vrijkomen. Over de precieze samenstelling blijkt weinig te vinden in de openbare literatuur. Het is daarom met de gevonden gegevens niet mogelijk te bepalen aan welke stoffen en in welke mate mensen die met isolatiematerialen werken blootgesteld worden, en dus of er sprake is van een risico voor hun gezondheid. Hetzelfde geldt voor bewoners van gebouwen waarin het wordt gebruikt. Uit voorzorg is het dan ook vooral belangrijk om bij het plaatsen van het isolatiemateriaal de veiligheidsvoorschriften van het product te volgen en de juiste beschermende maatregelen te nemen. Daarnaast is het van belang om geïsoleerde woningen goed te ventileren. Door een woning te isoleren verandert namelijk de luchtcirculatie en de ventilatiecapaciteit, wat het binnenmilieu negatief kan beïnvloeden. Voor een gezond binnenmilieu kan het daarom nodig zijn bestaande ventilatievoorzieningen na isolatie aan te passen. De uitkomsten van dit literatuuronderzoek zijn tijdens een workshop in december 2015 besproken met belanghebbenden (de ministeries van Infrastructuur en Milieu (IenM) en Binnenlandse Zaken en Koninkrijksrelaties (BZK), brancheorganisaties van producenten van isolatiematerialen, professionals uit de gezondheidszorg, de onafhankelijke voorlichtingsorganisatie Milieu Centraal, TNO en een organisatie van consumenten die gezondheidsklachten kregen nadat isolatiemateriaal in hun woning is aangebracht). De standpunten van deze partijen zijn overgenomen in dit rapport.

Het RIVM heeft verkennend onderzocht welke informatie in openbare literatuur beschikbaar is over de samenstelling van isolatiematerialen en welke stoffen eruit kunnen vrijkomen. Over de precieze samenstelling blijkt weinig te vinden in de openbare literatuur. Het is daarom met de gevonden gegevens niet mogelijk te bepalen aan welke stoffen en in welke mate mensen die met isolatiematerialen werken blootgesteld worden, en dus of er sprake is van een risico voor hun gezondheid. Hetzelfde geldt voor bewoners van gebouwen waarin het wordt gebruikt. Uit voorzorg is het dan ook vooral belangrijk om bij het plaatsen van het isolatiemateriaal de veiligheidsvoorschriften van het product te volgen en de juiste beschermende maatregelen te nemen. Daarnaast is het van belang om geïsoleerde woningen goed te ventileren. Door een woning te isoleren verandert namelijk de luchtcirculatie en de ventilatiecapaciteit, wat het binnenmilieu negatief kan beïnvloeden. Voor een gezond binnenmilieu kan het daarom nodig zijn bestaande ventilatievoorzieningen na isolatie aan te passen. De uitkomsten van dit literatuuronderzoek zijn tijdens een workshop in december 2015 besproken met belanghebbenden (de ministeries van Infrastructuur en Milieu (IenM) en Binnenlandse Zaken en Koninkrijksrelaties (BZK), brancheorganisaties van producenten van isolatiematerialen, professionals uit de gezondheidszorg, de onafhankelijke voorlichtingsorganisatie Milieu Centraal, TNO en een organisatie van consumenten die gezondheidsklachten kregen nadat isolatiemateriaal in hun woning is aangebracht). De standpunten van deze partijen zijn overgenomen in dit rapport.

At early stages of life, infant immature intestine is not fully developed, exposing the new-born to potential diseases. Compounds that can exert beneficial actions on the infant intestine are bioactive lactose-based oligosaccharides (LBOs). The natural source of LBOs is mother milk. When human milk is lacking, dietary supplementation with infant formula fortified with manufactured LBOs, such as galacto-oligosaccharides (GOS), is pursued. GOS have been shown to have several properties in common with HMOs. LBOs composition and intestinal fate is extensively described for humans, whereas they are hardly investigated for domestic animal. In this PhD thesis, composition of LBOs in equine and porcine colostrum were described and new structures were elucidated. The analysis were performed mainly using liquid chromatography and capillary electrophoresis techniques. High inter- and intra-individual variation were found for oligosaccharides present in equine and porcine milk. In vivo fermentation fate of porcine milk oligosaccharides (PMOs) was also described analysing PMOs as found in fecal samples of piglets. The results were correlated to existing literature on HMOs. Dietary oligosaccharides are partially present systemically, as suggested from HMO studies. GOS and PMOs in blood, urine and fecal samples from an in vivo feeding trial on piglet were described. Intact dietary oligosaccharides including GOS and milk oligosaccharides from the piglet diet were found in piglet blood and urine samples. All dietary oligosaccharides were fermented/absorbed in vivo, not being detectable in the piglet fecal samples. On the other hand, GOS in vitro fermentation by piglet inoculum delineate a unique fermentation profile regarding GOS size consumption compared to GOS in vitro fermentation by human fecal inoculum. Similar degradation profile regarding GOS linkage types was observed for GOS fermentation by piglet and human inocula.

Energy savings through a greenhouse cover of insulation glass requires a large investment. In the search for a cheaper alternative by a consortium of companies consisting of VDH Plastic Greenhouses, Van der Valk Horti Systems, AGC Chemicals Europe en Boal Systems a Glass-Film-greenhouse cover, better known as the 2SaveEnergy greenhouse concept was realized in summer 2014. The combination of clear glass with a diffuse ETFE film and a double screen mounted at a distance of only a few centimetres, in the year 2015, resulted in a low energy consumption and a better than expected good tomato production. During cultivation, the principles of the new cultivation methods were used. With respect to the common practice, the energy consumption was more than 50% lower at a minimum equal production. Energiebesparing door een isolerend kasdek van isolatieglas vergt een grote investering. In de zoektocht naar een goedkoper alternatief is door een consortium van bedrijven bestaande uit VDH Plastic Greenhouses, Van der Valk Horti Systems, AGC Chemicals Europe en Boal Systems een Glas-FilmKasdek, beter bekend als het 2SaveEnergy concept ontwikkeld en in de zomer van 2014 ook gerealiseerd. De combinatie van helder glas met een diffuse ETFE film en een dubbel scherm welke op slechts enkele centimeters afstand van elkaar gemonteerd is heeft in het teeltjaar 2015 tot een laag energiegebruik en een prima tomaten productie geleid. Tijdens de teelt zijn de principes van het nieuwe telen zoveel mogelijk aangehouden. Ten opzichte van de gangbare praktijk was het energiegebruik meer dan 50% lager bij een minimaal gelijke productie.

At early stages of life, infant immature intestine is not fully developed, exposing the new-born to potential diseases. Compounds that can exert beneficial actions on the infant intestine are bioactive lactose-based oligosaccharides (LBOs). The natural source of LBOs is mother milk. When human milk is lacking, dietary supplementation with infant formula fortified with manufactured LBOs, such as galacto-oligosaccharides (GOS), is pursued. GOS have been shown to have several properties in common with HMOs. LBOs composition and intestinal fate is extensively described for humans, whereas they are hardly investigated for domestic animal. In this PhD thesis, composition of LBOs in equine and porcine colostrum were described and new structures were elucidated. The analysis were performed mainly using liquid chromatography and capillary electrophoresis techniques. High inter- and intra-individual variation were found for oligosaccharides present in equine and porcine milk. In vivo fermentation fate of porcine milk oligosaccharides (PMOs) was also described analysing PMOs as found in fecal samples of piglets. The results were correlated to existing literature on HMOs. Dietary oligosaccharides are partially present systemically, as suggested from HMO studies. GOS and PMOs in blood, urine and fecal samples from an in vivo feeding trial on piglet were described. Intact dietary oligosaccharides including GOS and milk oligosaccharides from the piglet diet were found in piglet blood and urine samples. All dietary oligosaccharides were fermented/absorbed in vivo, not being detectable in the piglet fecal samples. On the other hand, GOS in vitro fermentation by piglet inoculum delineate a unique fermentation profile regarding GOS size consumption compared to GOS in vitro fermentation by human fecal inoculum. Similar degradation profile regarding GOS linkage types was observed for GOS fermentation by piglet and human inocula.

Energy savings through a greenhouse cover of insulation glass requires a large investment. In the search for a cheaper alternative by a consortium of companies consisting of VDH Plastic Greenhouses, Van der Valk Horti Systems, AGC Chemicals Europe en Boal Systems a Glass-Film-greenhouse cover, better known as the 2SaveEnergy greenhouse concept was realized in summer 2014. The combination of clear glass with a diffuse ETFE film and a double screen mounted at a distance of only a few centimetres, in the year 2015, resulted in a low energy consumption and a better than expected good tomato production. During cultivation, the principles of the new cultivation methods were used. With respect to the common practice, the energy consumption was more than 50% lower at a minimum equal production. Die Realisierung von Energieeinsparungen mithilfe von Gewächshausdächern aus Isolierglas erfordert meist hohe Investitionen. Auf der Suche nach einer kostengünstigeren Alternative hat ein Konsortium der Unternehmen VDH Plastic Greenhouses, Van der Valk Horti Systems, AGC Chemicals Europe und Boal Systems das Gewächshausdachkonzept ‘2SaveEnergy’ entwickelt und im Sommer 2014 realisiert. Die Kombination von Klarglas und diffuser ETFE-Folie als Bedachung mit einem doppelten Energieschirm mit einem Zwischenraumvon nur wenigen Zentimetern führte im Versuchsjahr 2015 zu einer guten Tomatenproduktion bei geringem Energieverbrauch. Die Produktion selbst erfolgte weitestmöglich nach den Grundsätzen der ‘Neuen Kulturverfahren’. Im Vergleich zur üblichen Praxis war der Energieverbrauch bei mindestens gleicher Produktion 50% geringer.

Energy savings through a greenhouse cover of insulation glass requires a large investment. In the search for a cheaper alternative by a consortium of companies consisting of VDH Plastic Greenhouses, Van der Valk Horti Systems, AGC Chemicals Europe en Boal Systems a Glass-Film-greenhouse cover, better known as the 2SaveEnergy greenhouse concept was realized in summer 2014. The combination of clear glass with a diffuse ETFE film and a double screen mounted at a distance of only a few centimetres, in the year 2015, resulted in a low energy consumption and a better than expected good tomato production. During cultivation, the principles of the new cultivation methods were used. With respect to the common practice, the energy consumption was more than 50% lower at a minimum equal production.

Op 27 september 2004 promoveerde Marco Kruijt aan Wageningen Universiteit op het proefschrift getiteld 'Molecular evolution of Cladosporium fulvum disease resistance genes in wild tomato'. De evolutie van het Cf-9 gen in de wilde tomatensoort L.pimpinellifolium is in detail bestudeerd. Naast het Cf-9 gen blijkt nog een resistentiegen, het 9DCgen, aanwezig. Het Cf-9 gen is ouder dan het 9DC gen en komt in verschillende wilde tomatensoorten voor. Hieruit blijkt ondermeer dat C. fulvum waarschijnlijk al een pathogeen van de 'oertomaat' was

Precies een jaar geleden startte Wageningen UR Glastuinbouw en een consortium van bedrijven met de bouw van een nieuwe, energiezuinige kas. Sleutelcomponent is een ventileerbaar spouwdek dat bestaat uit helder glas waaronder een duurzaam diffuus folie is aangebracht. Dit najaar maken betrokkenen de balans op, maar nu al lijkt de innovatie een aanwinst voor Het Nieuwe Telen. Het systeem oogt professioneel en bezoekers reageren positief.

Due to the globally increasing demand for chemicals and fuels and the high environmental impact and limited amount of fossil resources, there is a growing interest in green chemicals and fuels derived from renewable resources. As described in Chapter 1, one of the most feasible alternatives on the short term is microbial conversion of the sugars in biomass to fuels and chemicals in a biorefinery. To be economically and ethically feasible, non-food biomass should be used as a resource, which is often difficult with currently used production organisms. Also, to be economically feasible, the costs of green chemicals and fuels need to be further reduced to be below the costs of products based on fossil resources. To do so, other organisms than the currently most-used platform organisms such as Escherichia coli and Saccharomyces cerevisiae should be used. Ideally, this alternative organism is genetically accessible, has high productivity, titre and yield, is flexible in carbon source, robust, moderately thermophilic, acidophilic, facultatively anaerobic and has little nutritional requirements. The organisms that come closest to these criteria are thermophilic bacilli, which form a diverse class of organisms in the family of Bacillaceae. This thesis describes the isolation, characterization and metabolic engineering of Bacillus smithii, a novel potential thermophilic platform organism. Chapter 2 provides more detail on the use of thermophilic microorganisms as platform organisms for green chemical production in a biorefinery concept. As commercially available enzyme mixtures used in the simultaneous saccharification and fermentation (SSF) of biomass have their optimum temperature around 50-60°C, using a moderately thermophilic organism would reduce the costs of the SSF process compared to when using mesophiles by reducing the amount of required enzyme. Also, thermophilic processes are less prone to contaminations, and substrate and product solubility are increased. Several successful examples of the application of facultatively anaerobic thermophiles for green chemical production from lignocellulose in an SSF setting are for example Bacillus coagulans for lactic acid production and Bacillus licheniformis for 2,3-butanediol production. However, whereas strongly developed genetic toolboxes are available for current mesophilic production organisms, these tools are still in their infancy for thermophilic organisms. Such tools are required to optimize production and to study metabolism. Thermophilic organisms show a wide variety in metabolism and in many cases the metabolism of these organisms is still poorly understood, hampering full optimization. Chapter 2 furthermore provides an overview of transformation, integration and counter-selection methods currently used for thermophiles. Although several deletion mutants have been constructed using these methods, not all of them are entirely markerless and most are not suited as high-throughput engineering tools, stressing the need for further research in this area. Despite several facultatively anaerobic thermophiles being described as genetically accessible, this feature is still one the major bottlenecks in developing these organisms into platform organisms. Therefore, in Chapter 3, we set out to isolate a facultatively anaerobic, moderately thermophilic bacterium that was genetically accessible and produced high titers of organic acids. A total of 267 strains of different thermophilic bacilli species were isolated from compost and screened for C5 and C6 sugar utilization and acid production. The 44 best strains were screened for genetic accessibility via electroporation. Only 3 strains tested positive for this, namely Geobacillus thermodenitrificans strains ET 144-2 and ET 251 and B. smithii strain ET 138. In subsequent evaluations in lab-scale bioreactors at 55°C and pH 6.5 on glucose, the two G. thermodenitrificans strains performed poorly whereas B. smithii performed well with high titers, yields and productivity of mainly lactate. In similar lab-scale reactors, this strain also performed well on xylose and at pH 5.5 and was still able to perform for 48 at pH 4.5. The electroporation protocol for this strain was optimized, resulting in a maximum efficiency of 5x103 colonies per µg plasmid pNW33n. Two other B. smithii strains, among which the type strain DSM 4216T, were also shown to be transformable with pNW33n. This is the first time that genetic accessibility is described for B. smithii and it is the first step towards developing it into a platform organism, for which it appears to be suitable based on its efficient C5 and C6 sugar utilization and acid production profile. In order to become a platform organism and to study its atypical metabolism, a genetic toolbox needs to be established for B. smithii. Chapter 5 describes the development of a markerless gene deletion method for B. smithii. For strains ET 138 and DSM 4216T, the ldhL gene was markerlessly removed via double homologous recombination using plasmid pNW33n. Despite the replicative nature of this plasmid at 55°C, mixtures of single and double crossovers were readily obtained. A pure double crossover deletion mutant was obtained after several transfers on a more defined medium containing acetate or lactate and PCR-based screenings. To eliminate the possibility of mixed genotypes, we subsequently developed a lacZ-counter-selection system, which is based on the toxicity of high X-gal concentrations in the presence of the plasmid-encoded lacZ gene. Using this method, the sporulation-specific sigma factor sigF and pyruvate dehydrogenase complex E1-α pdhA were consecutively removed from the B. smithii ET 138 genome in a markerless way. An initial evaluation of the growth and production profiles of the mutant strains in tubes showed that removal of the ldhL gene eliminates l-lactate production and causes a severe decrease in anaerobic growth and production capacities. B. smithii mutants lacking the sigF gene were unable to sporulate and removal of the pdhA gene eliminated acetate production and rendered the strains auxotrophic for acetate.

Separation and purification of functional ingredients from raw or waste streams are often done via processes that include a chromatographic step using a packed bed of resin particles that have affinity for the ingredients to be separated. A column packed with these particles presents numerous bottlenecks when dealing with untreated or large streams: a trade-off between mass transfer and hydraulic permeability, a high pressure drop and susceptibility to plugging and fouling. The large equipment (column diameters) and volume of resin needed for a moderate pressure drop and a high capacity, poses problems of elevated costs and complex operation. Other technologies such as radial flow chromatography and polymeric resins membranes may represent an improvement in other applications (e.g. pharma or fine chemicals), but at this point their capacity and costs do not seem to be feasible for the separation of small molecules from larger food streams. The aim of the research discussed in this thesis was to find the principles that determine the suitability of different structured adsorbents, such as monoliths, for the selective adsorption and recovery of high-added value food ingredients of relatively low molecular weight, such as oligosaccharides and bioactive peptides. To ensure a cost-effective process and high capacity for small molecules, we demonstrated the feasibility of using activated carbon, and compared its adsorptive and hydraulic performance in two different structures: porous particles and channeled monoliths (”honeycomb” structures). Furthermore, we assessed the feasibility and window of operation of monoliths in terms of adsorbent and column volume required, compared to packed beds. To demonstrate the isolation of bioactive peptides from crude mixtures with activated carbon, we used activated carbon to recover a lacto-tripeptide IPP from a commercial hydrolyzate (1.5% w/w) in chapter 2. The purity of the initial crude mixture was doubled in the isolate, to up to 35% with a recovery of IPP of about 80% in the first cycles of adsorption. This was repeated over many consecutive adsorption-desorption cycles until the activated carbon packed bed column was exhausted. This exhaustion was found to be caused not only by the occupation of irreversible sites but also by pore blockage. Finally, guidelines were given for the competitive exhaustion of the adsorbent for process optimization in order to obtain higher purity and yield. In chapter 3 we showed the benefits of using channeled monoliths for processing untreated streams. We compared the use of channeled monoliths with a packed bed, both made of the same type of activated carbon, for the adsorption of the lactotripeptide IPP from a crude hydrolyzate. The results showed similar productivity and dynamic adsorptive capacities at comparable linear velocities and residence times, but the packed bed showed a strong pressure drop increase during continuous loading of the column and the same consecutive adsorption-desorption cycles as studied in chapter 2. This indicates the occurrence of pore blockage and plugging of the column. These fouling mechanisms were confirmed with two semi-empirical model analogies: one analogous to membrane fouling and another using an analogy with a set of parallel channels. The strong pressure drop increase was even more noticeable at high velocities (and short residence times). These trends were not observed in the channeled monoliths: no significant pressure drop increase was found here, and high velocities were eminently feasible. In chapter 4 the adsorption of lactose onto a bed of activated carbon particles and activated carbon channeled monoliths was described with a detailed chromatographic model, taking into account the different mass transfer resistances. First, the single component adsorption isotherm parameters were obtained using frontal analysis on both adsorbents. Second, the kinetics of adsorption of lactose on both activated carbon adsorbents were estimated using the shallow bed method, assuming an infinite bath. The uptake curves were fitted to the homogeneous surface diffusion model and the linear driving force approximation. The estimation of the intraparticle diffusion coefficient and the film mass transfer coefficient showed a similar intraparticle mass transfer performance during the uptake adsorptive process. Fitting of the breakthrough data to the general rate model describing the full column operation showed differences in performance during the overall column operation. These differences could be related to higher axial dispersion in the squared channeled monoliths. The difference between the experimentally-derived axial dispersion and he expected assuming tubular coated tubes, suggested that the squared shape was responsible for the inhomogeneity of the flow. In chapter 5, we presented guidelines for the configuration of industrial scale chromatographic separation of small molecules. A window was identified that defines the feasible configurations to use for the highest productivity for a given set of process requirements. The performance of different axial packed beds, channeled monoliths and a continuous monolith assuming silica as base material were compared by means of HETP (height equivalent of theoretical plates) and pressure drop relations. The relations as a function of velocity were used to calculate the resultant velocity and packing length for different conditions (efficiency, pressure drop, affinity constant and throughput). The specific productivity of channeled monoliths was shown to be up to 2.5 orders of magnitude higher than that of a packed bed. Therefore, at large scales (in which the pressure drops need to be limited, and the flow rate is high), channeled monoliths are preferred since they may reduce the equipment size up to 100 times and the required adsorbent volume up to 1000 times. Finally, in chapter 6 we discussed the suitability of activated carbon regarding its re-usability and purification potential in the separation of small food ingredients. The suitability of channeled monoliths for certain applications was also highlighted. Finally, other suitable adsorbents were suggested, and some future prospects in the selection of adsorbents were given.

Separation and purification of functional ingredients from raw or waste streams are often done via processes that include a chromatographic step using a packed bed of resin particles that have affinity for the ingredients to be separated. A column packed with these particles presents numerous bottlenecks when dealing with untreated or large streams: a trade-off between mass transfer and hydraulic permeability, a high pressure drop and susceptibility to plugging and fouling. The large equipment (column diameters) and volume of resin needed for a moderate pressure drop and a high capacity, poses problems of elevated costs and complex operation. Other technologies such as radial flow chromatography and polymeric resins membranes may represent an improvement in other applications (e.g. pharma or fine chemicals), but at this point their capacity and costs do not seem to be feasible for the separation of small molecules from larger food streams. The aim of the research discussed in this thesis was to find the principles that determine the suitability of different structured adsorbents, such as monoliths, for the selective adsorption and recovery of high-added value food ingredients of relatively low molecular weight, such as oligosaccharides and bioactive peptides. To ensure a cost-effective process and high capacity for small molecules, we demonstrated the feasibility of using activated carbon, and compared its adsorptive and hydraulic performance in two different structures: porous particles and channeled monoliths (”honeycomb” structures). Furthermore, we assessed the feasibility and window of operation of monoliths in terms of adsorbent and column volume required, compared to packed beds. To demonstrate the isolation of bioactive peptides from crude mixtures with activated carbon, we used activated carbon to recover a lacto-tripeptide IPP from a commercial hydrolyzate (1.5% w/w) in chapter 2. The purity of the initial crude mixture was doubled in the isolate, to up to 35% with a recovery of IPP of about 80% in the first cycles of adsorption. This was repeated over many consecutive adsorption-desorption cycles until the activated carbon packed bed column was exhausted. This exhaustion was found to be caused not only by the occupation of irreversible sites but also by pore blockage. Finally, guidelines were given for the competitive exhaustion of the adsorbent for process optimization in order to obtain higher purity and yield. In chapter 3 we showed the benefits of using channeled monoliths for processing untreated streams. We compared the use of channeled monoliths with a packed bed, both made of the same type of activated carbon, for the adsorption of the lactotripeptide IPP from a crude hydrolyzate. The results showed similar productivity and dynamic adsorptive capacities at comparable linear velocities and residence times, but the packed bed showed a strong pressure drop increase during continuous loading of the column and the same consecutive adsorption-desorption cycles as studied in chapter 2. This indicates the occurrence of pore blockage and plugging of the column. These fouling mechanisms were confirmed with two semi-empirical model analogies: one analogous to membrane fouling and another using an analogy with a set of parallel channels. The strong pressure drop increase was even more noticeable at high velocities (and short residence times). These trends were not observed in the channeled monoliths: no significant pressure drop increase was found here, and high velocities were eminently feasible. In chapter 4 the adsorption of lactose onto a bed of activated carbon particles and activated carbon channeled monoliths was described with a detailed chromatographic model, taking into account the different mass transfer resistances. First, the single component adsorption isotherm parameters were obtained using frontal analysis on both adsorbents. Second, the kinetics of adsorption of lactose on both activated carbon adsorbents were estimated using the shallow bed method, assuming an infinite bath. The uptake curves were fitted to the homogeneous surface diffusion model and the linear driving force approximation. The estimation of the intraparticle diffusion coefficient and the film mass transfer coefficient showed a similar intraparticle mass transfer performance during the uptake adsorptive process. Fitting of the breakthrough data to the general rate model describing the full column operation showed differences in performance during the overall column operation. These differences could be related to higher axial dispersion in the squared channeled monoliths. The difference between the experimentally-derived axial dispersion and he expected assuming tubular coated tubes, suggested that the squared shape was responsible for the inhomogeneity of the flow. In chapter 5, we presented guidelines for the configuration of industrial scale chromatographic separation of small molecules. A window was identified that defines the feasible configurations to use for the highest productivity for a given set of process requirements. The performance of different axial packed beds, channeled monoliths and a continuous monolith assuming silica as base material were compared by means of HETP (height equivalent of theoretical plates) and pressure drop relations. The relations as a function of velocity were used to calculate the resultant velocity and packing length for different conditions (efficiency, pressure drop, affinity constant and throughput). The specific productivity of channeled monoliths was shown to be up to 2.5 orders of magnitude higher than that of a packed bed. Therefore, at large scales (in which the pressure drops need to be limited, and the flow rate is high), channeled monoliths are preferred since they may reduce the equipment size up to 100 times and the required adsorbent volume up to 1000 times. Finally, in chapter 6 we discussed the suitability of activated carbon regarding its re-usability and purification potential in the separation of small food ingredients. The suitability of channeled monoliths for certain applications was also highlighted. Finally, other suitable adsorbents were suggested, and some future prospects in the selection of adsorbents were given.

Aerogel is een zeer kostbaar voor de ruimtevaart ontwikkeld basismateriaal. Bluedec is een isolatiemateriaal bestaande uit een non woven kunststof dat met deze aerogel geïmpregneerd is. Hierdoor ontstaat een zeer goed isolerend materiaal dat goedkoper is dan aerogel. De warmtegeleidingscoëfficiënt van Bluedec in de basisuitvoering is 0,0135 W/m*K . Dat is lager dan conventionele isolatiematerialen, zie ook pagina 4. Voordeel hiervan is dat vergelijkbare of betere warmte-isolatie kan worden bereikt met respectievelijk minder of dezelfde isolatieruimte. Er zijn verschillende uitvoeringen van het materiaal waardoor het een temperatuurbereik van -270 °C tot + 650 °C heeft. Bovendien is het een flexibel materiaal. Een nadeel is dat het basismateriaal stuift en daardoor voor veel toepassingen ‘ingepakt’ moet worden. Hier zijn diverse mogelijkheden voor. Tevens is er een gevacumeerde versie met een warmtegeleidingscoëfficiënt van 0,0045 W/m*K verkrijgbaar. Deze datasheet is opgebouwd in de PCMIEP-structuur met Bluedec als middelpunt. Dit document is opgeleverd in het project Innovatief Materialen Platform Twente (IMPT). In dit project heeft het IMPT 75 innovatieve materialen in kaart gebracht. Met een tiental materialen is toegepast onderzoek gedaan, zodat ondernemers en ontwerpers weten of en hoe zij deze kunnen toepassen.

In dit onderzoek is door middel van metingen in 92 woningen rondom de luchthaven Schiphol getracht inzicht te krijgen in de invloed van geluidsisolatie van woningen en eventueel veranderd ventilatiegedrag wegens geluid van buiten, op de concentraties luchtverontreiniging in woningen en het gehalte microbiele componenten in huisstof. In de lucht van de woonkamer werd de concentratie fijn stof (PM2.5), de concentratie roet, de concentratie Polycyclische Aromatische Koolwaterstoffen (PAK), de concentratie Vluchtige Organische Koolwaterstoffen (VOK) en de concentraties NO2 bepaald. Verder werd in huisstof afkomstig van de woonkamervloer van deze woningen het gehalte endotoxinen (afkomstig van gram-negatieve bacterien), het gehalte EPS(pen/asp) (afkomstig van schimmels), het gehalte beta(1,3)glucaan (ook afkomstig van schimmels) en het gehalte huisstofmijtallergeen (Der p 1) bepaald. Voor alle gemeten componenten werden geen statistisch significant aantoonbare verschillen gevonden tussen woningen met en woningen zonder aangebrachte geluidsisolatie. In het onderzoek was ook gevraagd of mensen minder gebruik maakten van ventilatiemogelijkheden wegens geluid van buiten. Voor geen van de gemeten componenten was een statistisch significant verschil aan te tonen tussen mensen die hun ventilatiegedrag aanpasten aan geluid van buiten en mensen die dat niet deden. Op basis van dit onderzoek kan geconcludeerd worden dat geluidsisolatie of verminderde ventilatie (zoals ervaren door de bewoners) wegens geluid van buiten niet zal leiden tot hogere concentraties van de hier onderzochte stoffen in de binnenlucht en in het huisstof.

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In dit onderzoek is door middel van metingen in 92 woningen rondom de luchthaven Schiphol getracht inzicht te krijgen in de invloed van geluidsisolatie van woningen en eventueel veranderd ventilatiegedrag wegens geluid van buiten, op de concentraties luchtverontreiniging in woningen en het gehalte microbiele componenten in huisstof. In de lucht van de woonkamer werd de concentratie fijn stof (PM2.5), de concentratie roet, de concentratie Polycyclische Aromatische Koolwaterstoffen (PAK), de concentratie Vluchtige Organische Koolwaterstoffen (VOK) en de concentraties NO2 bepaald. Verder werd in huisstof afkomstig van de woonkamervloer van deze woningen het gehalte endotoxinen (afkomstig van gram-negatieve bacterien), het gehalte EPS(pen/asp) (afkomstig van schimmels), het gehalte beta(1,3)glucaan (ook afkomstig van schimmels) en het gehalte huisstofmijtallergeen (Der p 1) bepaald. Voor alle gemeten componenten werden geen statistisch significant aantoonbare verschillen gevonden tussen woningen met en woningen zonder aangebrachte geluidsisolatie. In het onderzoek was ook gevraagd of mensen minder gebruik maakten van ventilatiemogelijkheden wegens geluid van buiten. Voor geen van de gemeten componenten was een statistisch significant verschil aan te tonen tussen mensen die hun ventilatiegedrag aanpasten aan geluid van buiten en mensen die dat niet deden. Op basis van dit onderzoek kan geconcludeerd worden dat geluidsisolatie of verminderde ventilatie (zoals ervaren door de bewoners) wegens geluid van buiten niet zal leiden tot hogere concentraties van de hier onderzochte stoffen in de binnenlucht en in het huisstof.

Many product or even waste streams in the food industry contain components that may have potential for e.g. functional foods. These streams are typically large in volume and the components of interest are only present at low concentrations. A robust and highly selective separation process should be developed for efficient isolation of the components. Affinity chromatography is such a selective method. Ligands immobilized to a stationary phase (e.g., a resin or membrane) are used to bind the component of interest. Affinity chromatography is, however, a costly process, due to the batch-wise operation, the large amount of solvents required and the high costs of the ligands and stationary phases. Therefore, its current use is mainly limited to lab-scale purifications and pharmaceutical applications. The aim of this research was to investigate the potential of affinity chromatography for the isolation of minor protein in the food industry. The discovery of the VHH ligand, based on the binding domain of a llama antibody, has led to a new class of highly selective ligands, which can be produced on a large scale. We studied the chromatography process to measure productivity, but also to develop a rational protocol for decisions on suitable stationary phases and process configurations. The research presented in this thesis provides insights in the opportunities and challenges for large-scale affinity chromatography. The isolation of protein using affinity chromatography requires several stages: adsorption, washing, and desorption. In Chapter 2, we studied these stages for the isolation of bovine serum albumin (BSA) from pure BSA solutions with high and low concentration and from actual feedstock, in this case cheese whey. A small-scale packed bed column was used to investigate the yield and productivity. BSA was retrieved in highly pure and concentrated form in the desorption stage. Furthermore, we found that the productivity of the system strongly depended on the point at which the adsorption stage is terminated. Acids or salts are commonly used to disrupt the bond between ligand and target protein during desorption. This results in the use of large quantities of chemicals, whilst the potential of other methods for desorption, such as an increase in temperature, is not fully explored. In Chapter 3 we measured the thermodynamics of the adsorption reaction between BSA and the VHH ligand with isothermal titration calorimetry (ITC). Temperature and pH were varied to find other conditions for desorption. A buffer with high pH could be used for desorption, and an increase of temperature seemed to weaken the bond between protein and ligand. However, the acidic buffer would in this case still be most effective. Apart from the bond between ligand and target protein, the stationary phase to which the ligand is immobilised plays a key role in the chromatography process. Many supports are available, of which we investigated a selection of resins for packed bed chromatography in Chapter 4. We found that some resins were unsuitable for our process due to their low adsorption capacity. A ranking and weighing method was presented to determine the optimal resin depending on the requirements of the process. An important issue we found for all the resins investigated, was the low adsorption capacity compared to other types of adsorptive chromatography processes, such as ion exchange chromatography. Therefore, we studied the immobilization of the ligand to three resins in more detail in Chapter 5. The efficiency of ligand immobilization depended on the ligand concentration used in the immobilization procedure. However, only approximately one out of five immobilized ligands was able to bind to the target. Improvement of ligand immobilization is therefore a potential route to increase the feasibility of affinity chromatography for large-scale processes. Eventually the lab-scale process has to be scaled-up to industrial scale. The commonly used axial flow column, essentially a cylinder filled with resin through which the feed flows in the axial direction, can have problems at scale-up, because of increased pressure drop as the column is lengthened. Therefore, scale-up usually takes place by widening the column. Another option is to use a radial flow column, in which the resin is confined between two concentric cylinders and liquid flows from the outside inwards or from the inside outwards. The radial flow column can be scaled up in height instead of width. In Chapter 6 we compared axial and radial flow affinity chromatography both experimentally and theoretically. We found that the differences in performance were minimal, because the process was limited by diffusion inside the resin particle. At a small process scale, radial flow columns are impractical in terms of size, but at a larger process scale they may compete with axial flow columns because of their smaller foot print and possibly lower construction costs. The research in this thesis was focused on a defined ligand-protein system and commercially available resins in packed-bed configuration. The potential of other stationary phases, such as non-porous (magnetic) particles, membranes and monoliths was therefore discussed in Chapter 7. We found that currently the packed bed of porous resin beads still seems to be the most suitable configuration. A radial flow column with porous affinity resin is in theory capable of isolating a low-concentrated protein from a large feed of 10 m3/h. However, the relatively low capacity of the resin, the limited liquid velocity, as well as large buffer usage and the current costs remain important issues to resolve to further expand the opportunities of affinity chromatography for minor protein isolation.

Many product or even waste streams in the food industry contain components that may have potential for e.g. functional foods. These streams are typically large in volume and the components of interest are only present at low concentrations. A robust and highly selective separation process should be developed for efficient isolation of the components. Affinity chromatography is such a selective method. Ligands immobilized to a stationary phase (e.g., a resin or membrane) are used to bind the component of interest. Affinity chromatography is, however, a costly process, due to the batch-wise operation, the large amount of solvents required and the high costs of the ligands and stationary phases. Therefore, its current use is mainly limited to lab-scale purifications and pharmaceutical applications. The aim of this research was to investigate the potential of affinity chromatography for the isolation of minor protein in the food industry. The discovery of the VHH ligand, based on the binding domain of a llama antibody, has led to a new class of highly selective ligands, which can be produced on a large scale. We studied the chromatography process to measure productivity, but also to develop a rational protocol for decisions on suitable stationary phases and process configurations. The research presented in this thesis provides insights in the opportunities and challenges for large-scale affinity chromatography. The isolation of protein using affinity chromatography requires several stages: adsorption, washing, and desorption. In Chapter 2, we studied these stages for the isolation of bovine serum albumin (BSA) from pure BSA solutions with high and low concentration and from actual feedstock, in this case cheese whey. A small-scale packed bed column was used to investigate the yield and productivity. BSA was retrieved in highly pure and concentrated form in the desorption stage. Furthermore, we found that the productivity of the system strongly depended on the point at which the adsorption stage is terminated. Acids or salts are commonly used to disrupt the bond between ligand and target protein during desorption. This results in the use of large quantities of chemicals, whilst the potential of other methods for desorption, such as an increase in temperature, is not fully explored. In Chapter 3 we measured the thermodynamics of the adsorption reaction between BSA and the VHH ligand with isothermal titration calorimetry (ITC). Temperature and pH were varied to find other conditions for desorption. A buffer with high pH could be used for desorption, and an increase of temperature seemed to weaken the bond between protein and ligand. However, the acidic buffer would in this case still be most effective. Apart from the bond between ligand and target protein, the stationary phase to which the ligand is immobilised plays a key role in the chromatography process. Many supports are available, of which we investigated a selection of resins for packed bed chromatography in Chapter 4. We found that some resins were unsuitable for our process due to their low adsorption capacity. A ranking and weighing method was presented to determine the optimal resin depending on the requirements of the process. An important issue we found for all the resins investigated, was the low adsorption capacity compared to other types of adsorptive chromatography processes, such as ion exchange chromatography. Therefore, we studied the immobilization of the ligand to three resins in more detail in Chapter 5. The efficiency of ligand immobilization depended on the ligand concentration used in the immobilization procedure. However, only approximately one out of five immobilized ligands was able to bind to the target. Improvement of ligand immobilization is therefore a potential route to increase the feasibility of affinity chromatography for large-scale processes. Eventually the lab-scale process has to be scaled-up to industrial scale. The commonly used axial flow column, essentially a cylinder filled with resin through which the feed flows in the axial direction, can have problems at scale-up, because of increased pressure drop as the column is lengthened. Therefore, scale-up usually takes place by widening the column. Another option is to use a radial flow column, in which the resin is confined between two concentric cylinders and liquid flows from the outside inwards or from the inside outwards. The radial flow column can be scaled up in height instead of width. In Chapter 6 we compared axial and radial flow affinity chromatography both experimentally and theoretically. We found that the differences in performance were minimal, because the process was limited by diffusion inside the resin particle. At a small process scale, radial flow columns are impractical in terms of size, but at a larger process scale they may compete with axial flow columns because of their smaller foot print and possibly lower construction costs. The research in this thesis was focused on a defined ligand-protein system and commercially available resins in packed-bed configuration. The potential of other stationary phases, such as non-porous (magnetic) particles, membranes and monoliths was therefore discussed in Chapter 7. We found that currently the packed bed of porous resin beads still seems to be the most suitable configuration. A radial flow column with porous affinity resin is in theory capable of isolating a low-concentrated protein from a large feed of 10 m3/h. However, the relatively low capacity of the resin, the limited liquid velocity, as well as large buffer usage and the current costs remain important issues to resolve to further expand the opportunities of affinity chromatography for minor protein isolation.

Precies een jaar geleden startte Wageningen UR Glastuinbouw en een consortium van bedrijven met de bouw van een nieuwe, energiezuinige kas. Sleutelcomponent is een ventileerbaar spouwdek dat bestaat uit helder glas waaronder een duurzaam diffuus folie is aangebracht. Dit najaar maken betrokkenen de balans op, maar nu al lijkt de innovatie een aanwinst voor Het Nieuwe Telen. Het systeem oogt professioneel en bezoekers reageren positief.

Vandaag is het de normaalste zaak van de wereld om elke woning te isoleren, maar eigenlijk is dit nog maar een zeer recente evolutie. Naar aanleiding van het Palestijns-Israëlisch conflict hebben de Arabische landen in 1973 de olietoevoer naar het Westen op een laag pitje gezet, waardoor de olieprijs spectaculair de lucht in schoot. In de nasleep van deze eerste oliecrisis is het besef gegroeid dat we zuinig moeten omspringen met fossiele brandstoffen, zij het om politieke, economische of ecologische redenen. In België heeft zich dat vertaald in het eerste isolatiedecreet in 1991, de EPB-wetgeving in 2006, en de huidige – verstrengde – EPB-wetgeving in 2011. Maar dit is nog niet het eindpunt: Europa heeft beslist dat in 2021 alle nieuwbouwwoningen bijna nul-energie gebouwen moeten zijn. De komende 10 jaar moet de bouwwereld dus nog een stap zetten die minstens zo groot is als de evolutie in de laatste 50 jaar. Energiezuinig bouwen bestaat niet uit één oplossing, maar is een combinatie van doordacht ontwerp, efficiënte technieken, en veel isolatie. Helaas zijn dikke pakketten isolatie niet altijd zo eenvoudig in te passen in een plat dak, of wordt een strakke detaillering van sommige aansluitingen onmogelijk. Maar mogelijks komt er hulp uit onverwachte hoek: misschien kan vacuümisolatie de oplossing bieden voor een aantal problemen. Dit innovatief isolatiemateriaal isoleert tot 5 maal beter dan traditionele isolatiematerialen, maar er zitten enkele adders onder het gras.

With the introduction of genetically modified (GM) crops the EU has demanded that individual member states enact measures to prevent inadvertent admixture ¿ through outcrossing ¿ of genetically modified organisms (GMOs) with products from conventional and organic farming. A literature review on outcrossing was prepared for the Coexistence Committee installed in the Netherlands in 2004. For sugar beet and potato, isolation distances do not appear to be of overriding importance, as true seeds are not part of the harvested product. The only route for admixture is through persistence of GM hybrid volunteers, and these should already be subject to strict control in good agricultural practice. Data on maize indicate that a distance larger than 25 m is needed to keep admixture below the EU labelling threshold of 0.9%, and larger than 250 m to remain below the 0.1% threshold as favoured by organic farming organizations. Oilseed rape is more complex because apart from pollen flow also persistence of volunteers in and outside arable fields, and hybridization with wild relatives play a role. At the present state of knowledge, isolation distances of 100¿200 m and rotation intervals of 6¿8 years might be warranted for the 0.9% threshold. It is as yet not clear whether a threshold of 0.1% is achievable in practice. The conclusions are compared with the measures recommended by the Dutch Coexistence Committee. De auteurs hebben een literatuuronderzoek gedaan naar de manieren waarop voorkomen kan worden dat aardappel, maïs, suikerbiet en koolzaad, verbouwd volgens de biologische landbouw methode, besmet raken met genetisch gemodificeerde zaden. De resultaten van dat onderzoek worden vervolgens vergeleken met de maatregelen die zijn aanbevolen door de Nederlandse commissie Co-existentie.