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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    Camelina Crambe And Insects
    Wubben, E.F.M. ; Blaauw, R. ; Loo, E.N. van; Togtema, K.A. - \ 2018
    Wageningen : Wageningen Food & Biobased Research
    biobased economy - innovations - crops - biomass - residual streams - insects - oils - camelina - crambe - agricultural wastes
    Measurements of transcripts, proteome and metabolite profiles
    Peters, Sander - \ 2017
    Fuel4Me - 7
    biobased economy - biobrandstoffen - algen - algenteelt - oliën - biobased economy - biofuels - algae - algae culture - oils
    The work described for this deliverable was carried out by DLO-PRI, in collaboration with WU, and aim ed to understanding lipid production in Phaeodactylum tricornutum . By means of transcriptome, proteome and metabolome analyses we aimed to provide insight into the one step lipid production performed by partner WU. Cultivation conditions were chosen to steer lipid profile towards most suitable composition for biofuel production.
    Structuring oil by protein building blocks
    Vries, Auke de - \ 2017
    Wageningen University. Promotor(en): Erik van der Linden, co-promotor(en): Elke Scholten. - Wageningen : Wageningen University - ISBN 9789463430760 - 167
    gelation - gels - proteins - mechanical properties - oils - solidification - gelering - gels - eiwitten - mechanische eigenschappen - oliën - hardwording

    Over the recent years, structuring of oil into ‘organogels’ or ‘oleogels’ has gained much attention amongst colloid-, material,- and food scientists. Potentially, these oleogels could be used as an alternative for saturated- and trans fats in food products. To develop oleogels as a suitable replacement for saturated fats, the requirements go beyond merely providing a solid appearance to an otherwise liquid oil. For food applications, the gelator should be a well-known ingredient for food manufacturers, have a good nutritional value, and contribute to ‘clean labelling’. Proteins meet all these requirements and could therefore be of high potential. The general concept of protein-based oil gelation fits well into the growing general interest to reduce solid fats from food products along with increase in flexibility in terms of choice of ingredients. In this thesis, the suitability of proteins as a structuring agent for liquid oil was investigated and the rheological behaviour was described. To create protein oleogels, heat-set whey protein gels and protein aggregates, or ‘building blocks’, are created in an aqueous environment. Then, the aqueous phase is exchanged for a liquid oil phase via an intermediate solvent. It was show that by using this procedure, the created protein building blocks are highly efficient in creating oleogels. It is encouraging to see that the interactions between proteins can be altered by simple changes to the system, such as changing the oil type, water addition, or applying a heat treatment. This leads to the possibility to effectively and substantially tune the rheological properties of the final oleogel, such as its gel strength or yielding behaviour.

    Oil slick fate in 3D : predicting the influence of (natural and chemical) dispersion on oil slick fate
    Zeinstra-Helfrich, Marieke - \ 2016
    Wageningen University. Promotor(en): Tinka Murk, co-promotor(en): W. Koops. - Wageningen : Wageningen University - ISBN 9789462579279 - 174
    oil spills - pollution - adverse effects - oils - dispersion - models - thickness - olieverontreinigingen - verontreiniging - nadelige gevolgen - oliën - dispersie - modellen - dikte

    In certain conditions, (part of) an oil spill can disappear from the water surface through a process called natural dispersion. One available oil spill response option is to enhance this process by addition of dispersants (chemical dispersion). An informed decision for such response requires insight in the oil slick size WITH and WITHOUT treatment. This thesis aims to enable such assessment of net effectiveness, by providing a strategy for modelling the dispersion process.

    A plunging jet test was developed for investigating entrainment and droplet breakup. Using this set up the relevance of oil layer thickness was proven and an algorithm to model droplet sizes of dispersed oil was defined. The findings were applied in a model simulating dispersion and resurfacing as well as the wind-driven differential transport between the floating slick and suspended droplets. The simulation outputs help assess the added value (or not) of dispersant application in reducing the surface oil slick size for different oil types and conditions.


    An economic model for offshore cultivation of macroalgae
    Dijk, Wim van; Schoot, Jan Rinze van der; Edwards, Maeve ; Queguineur, Benoit ; Champenois, Jennifer ; Mooney, Karen ; Barrento, Sara - \ 2015
    Swansea : Swansea University - 21
    biobased economy - biomass - biofuels - algae - algae culture - oils - seaweeds - seaweed culture - biobased economy - biomassa - biobrandstoffen - algen - algenteelt - oliën - zeewieren - zeewierenteelt
    Algae biomass is considered as a potential non-fossil source of raw materials to produce fuel, feed, chemicals and materials. For this purpose microalgae as well as macroalgae can be used, and in this report we focus on the latter. More than 99% of the world production of aquatic plants is produced in Asia (FAO 2012, Table 1). From the remaining 1% about 4% is cultivated in Europe. Important European countries with commercial seaweed cultivation are Denmark, Ireland and France. Depending on their pigmentation seaweed species are commonly grouped in brown, red and green seaweeds.
    Strain improvement of oleaginous microalgae
    Jaeger, L. de - \ 2015
    Wageningen University. Promotor(en): Gerrit Eggink; Rene Wijffels, co-promotor(en): Dirk Martens. - Wageningen : Wageningen University - ISBN 9789462574847 - 200
    algen - biomassa - oliën - productiviteit - opbrengsten - transcriptomica - triacylglycerol lipase - bioreactoren - transformatie - mutanten - algenteelt - biomassa productie - algae - biomass - oils - productivity - yields - transcriptomics - triacylglycerol lipase - bioreactors - transformation - mutants - algae culture - biomass production

    The increasing world population and living standards have enlarged the demand for food, feed, and for chemicals. Traditional fossil fuel based commodities need to be replaced, not only because these resources are finite, but also to relieve the impact of carbon emission and pollution, resulting from fossil fuel derived processes. Much attention is on using plants to produce sustainable, renewable alternatives to petrochemical based processes. Palm oil is the crop with the highest lipid yield known today, but the production of palm oil causes deforestation on a large scale. Microalgae are a promising platform for the production of sustainable commodity products. A commodity product that can be produced in microalgae is triacylglycerol (TAG). The TAG molecules that are accumulated in microalgae are comparable to the TAG profiles of commonly used vegetable oils, and can directly be applied for edible oil as well as for biodiesel production. Currently, microalgae derived products have proven to be functional and a potential replacement for conventional crops. However, microalgae derived products, especially TAGs, are not economically feasible yet. In order to make microalgal derived products a reality we need to decrease the production costs by smart technological solutions, biological understanding and metabolic engineering.

    To get more insight in the lipid accumulation mechanism of microalgae, and to define targets for future strain improvement strategies, transcriptome sequencing of the oleaginous microalgae Neochloris oleoabundans was done. This oleaginous microalga can be cultivated in fresh water as well as salt water. The possibility to use salt water gives opportunities for reducing production costs and fresh water footprint for large scale cultivation.

    In chapter 2 the lipid accumulation pathway was studied to gain insight in the gene regulation 24 hours after nitrogen was depleted. Oil accumulation is increased under nitrogen depleted conditions in a comparable way in both fresh and salt water. The transcriptome sequencing revealed a number of genes, such as glycerol-3-phosphate acyltransferase and via glycerol-3-phosphate dehydrogenase, that are of special interest and can be targeted to increase TAG accumulation in microalgae. NMR spectroscopy revealed an increase in proline content in saline adapted cells, which was supported by up regulation of the genes involved in proline biosynthesis. In addition to proline, the ascorbate-glutathione cycle seems to be of importance for successful osmoregulation by removal of reactive oxygen species in N. oleoabundans, because multiple genes in this pathway were upregulated under salt conditions. The mechanism behind the biosynthesis of compatible osmolytes in N. oleoabundans can be used to improve salt resistance in other industrially relevant microalgal strains.

    Another very promising candidate for TAG production is the oleaginous green microalga Scenedesmus obliquus.

    In chapter 3, UV mutagenesis was used to create starchless mutants, since no transformation approach was available for this species, due to its rigid and robust cell wall. All five starchless mutants that were isolated from over 3500 screened mutants, showed an increased triacylglycerol productivity. All five starchless mutants showed a decreased or completely absent starch content. In parallel, an increased TAG accumulation rate was observed for the starchless mutants and no substantial decrease in biomass productivity was perceived. The most promising mutant (Slm1) showed an increase in TFA productivity of 41% at 4 days after nitrogen depletion and reached a TAG content of 49.4% (%CDW).

    In chapter 4 the Slm1 strain was compared to the wild type strain using photobioreactors. In the wild type, TAG and starch accumulated simultaneously during initial nitrogen starvation, and starch was subsequently degraded and likely converted into TAG. The Slm1 did not produce starch and the carbon and energy acquired from photosynthesis was partitioned towards TAG synthesis. This resulted in an increase of the maximum TAG content in Slm1 to 57% (%CDW) compared to 45% (%CDW) in the wild type. Furthermore, it increased the maximum yield of TAG on light by 51%, from 0.144 in the wild type to 0.217 g TAG mol-1 photon-1 in the Slm1 mutant. No differences in photosynthetic efficiency between the Slm1 mutant and the wild type were observed, indicating that the mutation specifically improved carbon partitioning towards TAG and the photosynthetic capacity was not affected.

    To identify the mutation that caused the starchless phenotype of Slm1 the transcriptome of both the wild type and the Slm1 mutant was sequenced as described in chapter 5. A single nucleotide polymorphism (SNP) was discovered in the small subunit of the starch biosynthesis rate-controlling enzyme ADP-glucose pyrophosphorylase, which resulted in the introduction of a STOP codon in the messenger RNA of the enzyme. The characterization of the mutation increases the understanding of carbon partitioning in oleaginous microalgae, leading to a promising target for future genetic engineering approaches to increase TAG accumulation in microalgae.

    To use the insight that is gained in chapters 2-5 for metabolic engineering of TAG accumulation and carbon partitioning, a metabolic engineering toolbox is required. However, the development of transformation protocols for new and less well studied industrially relevant microalgae is challenging. In chapter 6, a simple and effective tool for the optimization of transformation protocols is proposed. Optimal voltage settings were determined for five microalgae: C. reinhardtii, Chlorella vulgaris, N. oleoabundans, S. obliquus, and Nannochloropsis sp. This method can be used to speed up the screening process for species that are susceptible for transformation and to successfully develop transformation strategies for industrially relevant microalgae, which lack an efficient transformation protocol.

    In addition to the increase in productivity, improving the quality in terms of fatty acid composition of TAG molecules would be desired as well. For example, the accumulation of stearic acid rich TAG molecules is of special interest, because of the improved structural properties. The lipid accumulating starchless mutant of the model species C. reinhardtii BAFJ5 was used as model species in chapter 7, since genetic toolbox is well established for this species. In this chapter, stearoyl-ACP desaturase (SAD), is silenced by artificial microRNA. The mRNA levels for SAD were reduced after the silencing construct was induced. In one of the strains, the reduction in SAD mRNA resulted in a doubling of the stearic acid content in triacylglycerol molecules, which shows that increasing the fraction of stearic acid in TAG is possible. Furthermore, we hypothesize that in addition to direct conversion in the chloroplast, C. reinhardtii is able to redirect stearic acid from the chloroplast to the cytosol and convert it to oleic acid in the endoplasmic reticulum by stearoyl-CoA desaturase.

    In chapter 8, an outlook is given on microalgal strain improvement strategies for the future, reflecting on the results obtained in this thesis. Also a roadmap is suggested to get genetically modified microalgal derived products on the market. The results presented in this thesis, provide a significant improvement in the understanding of TAG accumulation and carbon partitioning in oleaginous microalgae. Furthermore, improved microalgal strains with increased TAG accumulation or improved TAG fatty acid composition under nitrogen depleted conditions were generated. In addition, an outlook is presented in which the major bottlenecks are presented in future industrial applications of microalgae.

    The dynamics of oil accumulation in Scenedesmus obliquus
    Breuer, G. - \ 2015
    Wageningen University. Promotor(en): Rene Wijffels, co-promotor(en): Dirk Martens; Packo Lamers. - Wageningen : Wageningen University - ISBN 9789462572348 - 268
    algen - stikstof - uithongering - triacylglycerolen - productiviteit - fotosynthese - koolstof - tussenmuren - oliën - algae - nitrogen - starvation - triacylglycerols - productivity - photosynthesis - carbon - partitions - oils

    .Abstract long

    Global demands for food and biofuels increase rapidly, together with an increase of concerns for depleting fossil resources and climate change. New sustainable sources of vegetable oil, from now on referred to as triacylglycerol (TAG), are therefore highly desired. Arable land to produce these TAGs is however limited. Microalgae have the potential to achieve much higher TAG productivities than commonly used terrestrial plants and can be cultivated on non-arable land. Microalgae are therefore often considered as a promising alternative natural-source of TAGs. Microalgae can accumulate up to 50% of their weight as TAGs, but only do so in response to nitrogen starvation. At the same time, nitrogen starvation also affects many other cellular processes, including photosynthesis. At the start of the work presented in this thesis, little was known about the quantitative aspects of photosynthesis and TAG production during nitrogen starvation. This contributed to a large uncertainty in what could be expected from microalgae. This thesis therefore provides a quantitative understanding of the microalgal response to nitrogen starvation, that can be used to understand and optimize TAG production.

    The differences between microalgae species in their response to nitrogen starvation are characterized. It was found that the difference in the response to nitrogen starvation between microalgae could be characterized in 1) how long the species could retain their photosynthetic efficiency during nitrogen starvation, 2) how much the species could in increase in biomass concentration in the absence of a nitrogen source, and 3) which fraction of the newly made biomass constitutes of TAG. The microalga species S. obliquus was chosen as the most suitable species for TAG production and used in all further studies.

    It is quantified how process conditions, such as the light intensity, pH, and temperature, influence TAG production during nitrogen starvation in S. obliquus. It was found that TAG could be produced in the ranges pH 5-9, temperature of 20-35°C, and incident light intensity of 200-1500 µmol m-2 s-1. The light intensity did not affect the maximum TAG content. The light intensity did, however, have a major effect on the photosynthetic efficiency. Suboptimal pH values and temperatures resulted in both a reduction in photosynthetic efficiency and reduction in maximum TAG content.

    It was found that during nitrogen starvation, at best approximately half of the biomass produced during nitrogen starvation is TAG. Large amounts of starch were produced simultaneously. This simultaneous starch and TAG production was therefore investigated in more detail. It was investigated how the carbon partitioning ratio (the ratio between fatty acid and starch synthesis rates), and the photosynthetic efficiency during nitrogen starvation, are influenced by the light intensity during nitrogen starvation and by the photoacclimated state at the onset of nitrogen starvation. It was found that the ratio between starch and fatty acid synthesis strongly correlated to the extent of nitrogen starvation, quantified as the biomass nitrogen content. Immediately after nitrogen depletion, mostly starch was made, but when nitrogen starvation progressed, this ratio shifted in favour of fatty acid synthesis. When nitrogen starvation progressed further, only fatty acids were made. Hereafter, the initially accumulated starch was degraded while fatty acid synthesis continued. The effects caused by the photoacclimated state persisted during nitrogen starvation. This did however not affect the photosynthetic efficiency or the carbon partitioning ratio during nitrogen starvation. The light intensity during nitrogen starvation had a major impact on the photosynthetic efficiency, but only a minor impact on the carbon partitioning ratio.

    Because large amounts of starch are produced during nitrogen starvation in wild-type S. obliquus, it is investigated how starchless mutants of S. obliquus can be used to improve TAG production. The carbon-partitioning of the wild-type and the slm1 starchless mutant of S. obliquus are therefore compared. It was found that the starchless mutant diverted all photosynthetic capacity, that was used for starch synthesis in the wild-type, towards TAG synthesis. This resulted in much higher TAG accumulation rates during initial nitrogen starvation. Furthermore, it was found that the efficiency of photosynthesis was not negatively affected in this starchless mutant. Altogether, the TAG yield on light increased by 51%.

    Using these insights, a mechanistic model was developed that describes photosynthesis and carbon partitioning during nitrogen starvation. The model was validated using experimental data from both the wild-type and starchless mutant of S. obliquus. This model was used to investigate how TAG production could be improved by advances in reactor design and strain improvement. Projections are made for productivities that seem feasible when various technologies are implemented in the microalgal cultivation process, using S. obliquus as a case-study.

    Finally, the findings of this thesis are used to evaluate the outcomes of techno-economic and life cycle analysis (LCA) studies that investigated the cost-price and net energy ratio of microalgal products, mostly biodiesel. It was found that the biomass productivity and biochemical composition associated with the cultivation of microalgae are large uncertainties in the input values for these studies. Several scenarios for microalgal cultivation are therefore presented based on the findings of this thesis. For each scenario, productivities, biochemical compositions, and nutrient requirements are provided that can be used as more realistic input values for techno-economic and LCA studies. It was concluded that the TAG productivity is commonly overestimated by 3 to 6-fold. According to these studies, approximately half of the costs and energy are used in the cultivation step. It was therefore concluded that these techno-economic and LCA studies underestimate the cost-price and energy consumption by 2 to 3.5-fold. The future improvements in productivity that might seem feasible according to the model simulations, could potentially improve the productivity such that it approaches the productivity that is commonly assumed as the base-case in current techno-economic and LCA studies. These advances in productivity can help to reduce the cost-price and specific energy consumption, but in addition, a reduction in costs and energy consumption of photobioreactors is needed before microalgal TAG production can be commercialized.

    Rheological behaviour of fibre-rich plant materials in fat-based food systems
    Bonarius, G.A. ; Vieira, J.B. ; Goot, A.J. van der; Bodnar, I. - \ 2014
    Food Hydrocolloids 40 (2014). - ISSN 0268-005X - p. 254 - 261.
    suspension rheology - sugar dispersions - chocolate - oils - emulsifiers - particles - sucrose - forces
    The potential use of fibre-rich materials as bulking agents to replace sucrose in chocolate confectionary products is investigated. Since the rheological behaviour of the molten chocolate mass is key in chocolate production, the rheology of fibre-rich materials in medium chain triglycerides (MCT) is studied and compared to the rheology of sucrose in MCT. The materials studied are side streams of the fruit and vegetable processing industry: lemon peels, spent grain, grape pomace and pecan fibre. All suspensions showed shear thinning behaviour at volume fractions >0.2, where side stream materials showed lower shear thinning behaviour than sucrose. The values for the maximum packing fraction, obtained via the Maron–Pierce equation and using the Casson Plastic Viscosities, were lower for the side stream materials than for sucrose. Addition of lecithin resulted in a decrease in the Casson Yield Value of sucrose suspensions, which was not observed with the fibre-rich materials. The rheological behaviour of the fibre-rich materials suspended in MCT is explained by the effective volume of the irregularly shaped particles. The behaviour of sucrose suspensions is explained by the formation of aggregates, which seem to be promoted by water bridges between the particles. Overall, the behaviour of the sucrose dispersions was very different compared to the other materials with respect to the shear thinning behaviour, the impact of lecithin as well as the impact of water. Therefore it is suggested that only partial replacement of sucrose by fibre-rich materials will be successful in industrial product development.
    Insect lipid profile: aqueous versus organic solvent-based extraction methods
    Tzompa Sosa, D.A. ; Yi, L. ; Valenberg, H.J.F. van; Boekel, M.A.J.S. van; Lakemond, C.M.M. - \ 2014
    Food Research International 62 (2014). - ISSN 0963-9969 - p. 1087 - 1094.
    edible insects - fatty-acids - nutrient composition - food - invertebrates - meat - seed - oils
    In view of future expected industrial bio-fractionation of insects, we investigated the influence of extraction methods on chemical characteristics of insect lipids. Lipids from Tenebrio molitor, Alphitobius diaperinus, Acheta domesticus and Blaptica dubia, reared in the Netherlands, were extracted by two industrial extraction processes (aqueous and Soxhlet) and one laboratory method (Folch extraction). Chemical characterization in terms of fatty acid composition (GC-FID), triacylglycerol profile (GC) and lipid classes (TLC) was performed on all the extracted lipids. The major findings on lipid chemical characterization were the following: (1) T. molitor had the highest lipid content around 13%; (2) the highest yield was obtained using Folch extraction, and the lowest yield using the aqueous method (from 19 to 60% related to the lipid recovery of Folch extraction); (3) ¿-3 fatty acids,which are related to health benefits, weremost abundant in lipids fromaqueous extraction,while¿-6 fatty acids were most abundant in Folch extractions, except for B. dubia; (4) lipids from Folch and Soxhlet extractions contained free fatty acids and partial glycerides, which were absent in aqueous extractions; (5) triacylglycerol distribution is similar among insect species, with high levels of ECN 50–54 and low amounts of ECN 36–38. In conclusion, aqueous extraction gave the lowest lipid yield, but provided a lipid extract low in ¿-6/¿-3 ratio and with less polar lipids than Soxhlet and Folch extractions. These characteristics are desirable in edible lipids. This is the first time that the triacylglycerol profile of insect lipids is reported. It is also the first time that C18:1 and C18:2 are reported as separated isomers and that trans isomers of C16:1 and C18:1 are reported in insect lipids.
    Comparison of Tungsten and Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Oleic Acid
    Hollak, S.A.W. ; Gosselink, R.J.A. ; Es, D.S. van; Bitter, J.H. - \ 2013
    ACS Catalysis 3 (2013)12. - ISSN 2155-5435 - p. 2837 - 2844.
    stearic-acid - fatty-acids - ruthenium catalysts - diesel production - reaction pathways - deoxygenation - biodiesel - hydrocarbons - adsorption - oils
    Group 6 (W, Mo) metal carbide catalysts are promising alternatives to hydrodesulfurization (NiMo, CoMo) catalysts and group 10 (Pd) type catalysts in the deoxygenation of vegetable fats/oils. Herein, we report a comparison of carbon nanofiber-supported W2C and Mo2C catalysts on activity, selectivity, and stability for the hydrodeoxygenation of oleic acid to evaluate the catalytic potential for the upgrading of fat/oil feeds. W2C/CNF was more selective toward olefins, whereas Mo2C/CNF was more selective toward paraffins. This was related to the hydrogenation activities of the respective metal carbides. Mo2C/CNF showed higher activity and stability compared with W2C/CNF.
    Functionalized carbon nanofibers as solid-acid catalysts for transesterification
    Stellwagen, D.R. ; Klis, F. van der; Es, D.S. van; Jong, K.P. de; Bitter, J.H. - \ 2013
    ChemSusChem 6 (2013)9. - ISSN 1864-5631 - p. 1668 - 1672.
    ordered mesoporous carbon - heterogeneous catalysts - biodiesel - nanotubes - chemistry - black - ions - oils
    Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient catalyst for the transesterification of triolein and methanol, outperforming conventional sulfonated carbons in both stability and activity per acid site. Upon comparing CNFs with varying degrees of functionalization, a linear correlation between sulfonic acid sites and catalytic performance was found.
    Isolation, identification and activity of natural antioxidants from horehound (Marrubium vulgare L.) cultivated in Lithuania
    Pukalskas, A. ; Venskutonis, P.R. ; Salido, S. ; Waard, P. de; Beek, T.A. van - \ 2012
    Food Chemistry 130 (2012)3. - ISSN 0308-8146 - p. 695 - 701.
    plant-extracts - liquid-chromatography - glycosides - online - leaves - iran - oils
    In an earlier screening of Lithuanian plants, horehound (Marrubium vulgare) showed good antioxidant activity and as this species is used in herbal teas and cough pastilles it was selected for further investigation. Some fractions of the aerial parts were strong scavengers of the model free radicals DPPH and ABTS'. Activity in the beta-carotene bleaching assay and the rapeseed oil oxidation assay was lower. Several active compounds were observed in the crude methanol-water extract, and in butanol and methyl tert-butyl ether fractions using HPLC with on-line radical scavenging detection. After multi-step fractionation of these fractions five compounds possessing radical scavenging activity were purified and their structures were elucidated by NMR and MS as 5,6-dihydroxy-7,4'-dimethoxyflavone (syn. ladanein), 7-O-beta-glucopyranosyl luteolin, 7-O-beta-glucuronyl luteolin, verbascoside and forsythoside B. Their activities were tested in off-line DPPH and ABTS(+) free radical scavenging assays, and compared with the antioxidants rosmarinic acid and Trolox. (C) 2011 Elsevier Ltd. All rights reserved.
    Modeling lipid accumulation in oleaginous fungi in chemostat cultures: I. Development and validation of a chemostat model for Umbelopsis isabellina
    Meeuwse, P. ; Tramper, J. ; Rinzema, A. - \ 2011
    Bioprocess and Biosystems Engineering 34 (2011)8. - ISSN 1615-7591 - p. 939 - 949.
    solid-state fermentation - fatty-acid-composition - gamma-linolenic acid - mortierella-isabellina - mucor-circinelloides - biodiesel production - malic enzyme - carbon - growth - oils
    Lipid-accumulating fungi may be able to produce biodiesel precursors from agricultural wastes. As a first step in understanding and evaluating their potential, a mathematical model was developed to describe growth, lipid accumulation and substrate consumption of the oleaginous fungus Umbelopsis isabellina (also known as Mortierella isabellina) in submerged chemostat cultures. Key points of the model are: (1) if the C-source supply rate is limited, maintenance has a higher priority than growth, which has a higher priority than lipid production; (2) the maximum specific lipid production rate of the fungus is independent of the actual specific growth rate. Model parameters were obtained from chemostat cultures of U. isabellina grown on mineral media with glucose and NH4+. The model describes the results of chemostat cultures well for D > 0.04 h-1, but it has not been validated for lower dilution rates because of practical problems with the filamentous fungus. Further validation using literature data for oleaginous yeasts is described in part II of this paper. Our model shows that not only the C/N-ratio of the feed, but also the dilution rate highly influences the lipid yield in chemostat cultures.
    Dioxin monitoring in fats oils for the feed industry
    Asselt, E.D. van; Sterrenburg, P. - \ 2011
    Wageningen : Rikilt - Institute of Food Safety (Report / RIKILT, Institute of Food Safety 2011.004) - 37
    dioxinen - monitoring - vetten - oliën - veevoederindustrie - analytische scheikunde - productieprocessen - voedselveiligheid - dioxins - monitoring - fats - oils - feed industry - analytical chemistry - production processes - food safety
    The aim of the present project was to determine the most critical steps in the production of fats and oils. First, production processes of vegetables oils, animal fat, fish oil, biodiesel and fat blending were studied and experts from the industry as well as in-house dioxin experts were consulted to identify the most critical steps. Then, monitoring data for vegetable oil, animal fat and fish oil were analysed to determine which products have an increased risk of dioxin contamination.
    Maatregelen ter vermindering van fijnstofemissie uit de pluimveehouderij: validatie van een oliefilmsysteem op vleeskuikenbedrijven = Measures to reduce fine dust emission from poultry houses: validation of an oil spraying system on broiler farms
    Winkel, A. ; Mosquera, J. ; Harn, J. van; Nijeboer, G.M. ; Ogink, N.W.M. ; Aarnink, A.J.A. - \ 2011
    Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 392) - 28
    pluimveehouderij - vleeskuikens - fijn stof - emissie - stofbestrijding - meting - oliën - stalklimaat - poultry farming - broilers - particulate matter - emission - dust control - measurement - oils - stall climate
    In this study, the fine dust emission reduction of an oil spraying system was determined through validation measurements on broiler farms.
    Lipid oxidation promotes acrylamide formation in fat-rich model systems
    Capuano, E. ; Oliviero, T. ; Açar, Ö. ; Gökmen, V. ; Fogliano, V. - \ 2010
    Food Research International 43 (2010)4. - ISSN 0963-9969 - p. 1021 - 1026.
    maillard reaction - phenylalanine - antioxidant - products - foods - oils
    Lipid oxidation is one of the major chemical reactions occurring during food processing or storage and may have a strong impact on the final quality of foods. A significant role of carbonyl compounds derived from lipid oxidation in acrylamide formation has been recently proposed. In this work, the effect of lipid oxidation level on acrylamide formation was investigated by thermal treatment of differently formulated fat-rich model systems. Results showed that lipid oxidation positively influenced the formation of acrylamide. The effect was more evident in sugar-free system where lipid become the main sources of carbonyls. Catechins reduced acrylamide formation presumably by trapping carbohydrates and/or preventing lipid oxidation. More acrylamide was formed in model systems composed with sunflower oil than in those containing palm oil which is less susceptible to oxidation. In systems containing higher amount of water, acrylamide formation was delayed due to evaporative cooling. In these systems, the effect of catechin was more pronounced and the effect of lipid oxidation became detectable only after a prolonged reaction time. These findings suggested that lipid oxidation could become a relevant factor for acrylamide formation, particularly for dry foods with low carbohydrate content.
    Maatregelen ter vermindering van fijnstofemissie uit de pluimveehouderij : alternatieve manieren van aanbrengen oliefilm op strooisel = Measures to reduce fine dust from poultry houses : alternative ways of oil film application on litter
    Slingerland, R. ; Ooster, A. van 't; Harn, J. van; Hattum, T.G. van; Aarnink, A.J.A. - \ 2010
    Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 348) - 22
    luchtkwaliteit - pluimvee - stofbestrijding - oliën - strooisel - fijn stof - emissie - pluimveehouderij - air quality - poultry - dust control - oils - litter (plant) - particulate matter - emission - poultry farming
    In this desk study alternative ways of oil application to reduce dust emission from poultry houses were investigated.
    Influence of the biobased economy on agricultural markets. Preperation of a modelling approach
    Nowicki, P.L. ; Leeuwen, M.G.A. van; Bos, H.L. ; Chant, L.J. ; Molenveld, K. ; Tabeau, A.A. - \ 2010
    Den Haag : LEI Wageningen UR (LEI report 2010-026) - ISBN 9789086154319 - 57
    biomassa - biomassa productie - oliën - economisch beleid - nederland - biobased economy - marktanalyse - productieprocessen - biomass - biomass production - oils - economic policy - netherlands - biobased economy - market analysis - production processes
    This report is the conclusion of research undertaken to better understand the impact of the developing biobased economy on agricultural land markets. This has involved understanding the true dimension of the biobased economy, namely the large range of products for which a biobased component exists or could exist, and in this regard the likely evolution in the substitution of elements produced from fossil oil. This research is also a first step to determine whether the overall result of the development of the biobased economy will be positive, negative or neutral for the Dutch economy as a whole.
    Identification and analysis of interactions between sea use functions
    Wal, J.T. van der; Quirijns, F.J. ; Leopold, M.F. ; Slijkerman, D.M.E. ; Jongbloed, R.H. - \ 2009
    Den Helder : IMARES (Report / IMARES Wageningen UR C132/09) - 34
    windmolens - parken - noordzee - mariene parken - nutfunctie - zeetransport - oliën - gasproductie - windmills - parks - north sea - marine parks - utility functions - sea transport - oils - gas production
    This report focuses on the interactions both positive and negative between offshore wind energy and the non-wind sea use functions.Some sea use functions can co-exist without substantial negative effects. Other combinations are problematic or even impossible and should be avoided. Therefore the interactions of the sea use functions are of importance.
    Inventory of current and future presence of non-wind sea use functions
    Wal, J.T. van der; Quirijns, F.J. ; Leopold, M.F. ; Slijkerman, D.M.E. ; Jongbloed, R.H. - \ 2009
    Den Helder : IMARES (Report / IMARES Wageningen UR C131/09) - 71
    windmolens - parken - noordzee - mariene parken - nutfunctie - zeetransport - oliën - gasproductie - windmills - parks - north sea - marine parks - utility functions - sea transport - oils - gas production
    In order to assess the suitability of locations on the Central and Southern North Sea for wind parks present sea use functions should also be taken into account. These sea use functions comprise shipping, oil and gas extraction, fisheries, cables and pipelines, military activities, sand extraction, radar interference and nature conservation. IMARES has collected data on these other sea use functions. Data was gathered from several national institutions, with a good deal of help from our project partners in identifying the best available sources.
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