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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    Elevated viscosities in a simulated moving bed for γ-aminobutyric acid recovery
    Schultze-Jena, A. ; Boon, M.A. ; Vroon, R.C. ; Bussmann, P.J.Th. ; Janssen, A.E.M. ; Padt, A. van der - \ 2020
    Journal of Separation Science 43 (2020)7. - ISSN 1615-9306 - p. 1256 - 1264.
    chromatography - concentration profile - productivity - simulated moving bed - viscosity

    Process streams of agro-food industries are often large and viscous. In order to fractionate such a stream the viscosity can be reduced by either a high temperature or dilution, the former is not an option in case of temperature sensitive components. Such streams are diluted prior to chromatographic fractionation, resulting in even larger volumes and high energy costs for sub-sequential water removal. The influence of feed viscosity on the performance of simulated moving bed chromatography has been investigated in a case study of the recovery of a γ-aminobutyric acid rich fraction from tomato serum. This work addresses the chromatographic system design, evaluates results from a pilot scale operation, and uses these to calculate the productivity and water use at elevated feed concentration. At the two higher feed viscosities (2.5 and 4 mPa·s) water use is lower and productivity higher, compared to the lowest feed viscosity (1 mPa·s). The behavior of the sugars for different feed viscosities can be described well by the model using the ratio of feed to eluent as dilution factor. The behavior of γ-aminobutyric acid is highly concentration dependent and the recovery could not be accurately predicted.

    Sugar Union extracts protein from waste stream: From worthless leaves to valuable powder
    Bussmann, Paul - \ 2020
    High viscosity preparative chromatography for food applications
    Schultze-Jena, A. ; Boon, M.A. ; Vroon, R.C. ; Bussmann, P.J.Th. ; Janssen, A.E.M. ; Padt, A. van der - \ 2020
    Separation and Purification Technology 237 (2020). - ISSN 1383-5866
    Food fractionation - Preparative chromatography - Productivity - System size - Viscosity

    The strength of chromatography lies in the ability of fine-tuning recovery for specific target components or fractions of interest. A downside of industrial chromatography is the need to dilute streams, as it is often applied today. This article challenges the conventional low concentration of input streams and investigates size exclusion chromatography at concentrated streams of high viscosity. Chromatographic operation with concentrated streams leads to an increased pressure drop over the column and decreased mass transfer kinetics, but also lower volumes compared to diluted streams. The objective of this research was to investigate separation performance and system dimensions as a function of viscosity for food type streams, in scenarios where viscosity is not caused by target components. Disadvantages due to increased stream volume with decreasing concentration and benefits due to decreased viscosity were evaluated, aiming to find minimal column volume. Separation performance was evaluated for a range of target components in a preparative lab-scale system using a size exclusion resin and mobile phase viscosities in the range of 1.2–8.7 mPa⋅s. Mobile phases were viscosified through addition of sucrose, glycerol, or dextran. Change in mass transfer resistance, measured via van Deemter curves, was related to the change in diffusivity through viscosity. The analysis of different viscosifying agents emphasized the influence of viscosity inside the pores, rather than viscosity of the bulk phase. The viscosity inside the pores was calculated via the partition coefficient of each viscosifying agent. Based on the slopes of van Deemter curves, column dimensions were calculated for different scenarios, assuming a non-compressible stationary phase. Column volume remained constant with stream dilution from 8.7 mPa⋅s down to about 2.5 mPa⋅s. However, at the same time column geometry changed to thinner and longer columns with decreasing viscosity, in order to accommodate throughput and pressure drop. When diluting to even lower viscosities, column volume increased, since stream viscosity is less sensitive to stream concentration at the low viscosity range. These results are relevant to a wide range of industries utilizing weak interaction chromatography, especially those where the main driver of process development is cost reduction and where a trade-off between purity, yield, and costs has to be made.

    Predicting intraparticle diffusivity as function of stationary phase characteristics in preparative chromatography
    Schultze-Jena, A. ; Boon, M.A. ; Winter, D.A.M. de; Bussmann, P.J.T. ; Janssen, A.E.M. ; Padt, A. van der - \ 2020
    Journal of Chromatography. A, Including electrophoresis and other separation methods 1613 (2020). - ISSN 0021-9673
    Intraparticle diffusivity - Parallel pore model - Porosity - Preparative chromatography

    Diffusion inside pores is the rate limiting step in many preparative chromatographic separations and a key parameter for process design in weak interaction aqueous chromatographic separations employed in food and bio processing. This work aims at relating diffusion inside porous networks to properties of stationary phase and of diffusing molecules. Intraparticle diffusivities were determined for eight small molecules in nine different stationary phases made from three different backbone materials. Measured intraparticle diffusivities were compared to the predictive capability of the correlation by Mackie and Meares and the parallel pore model. All stationary phases were analyzed for their porosity, apparent pore size distribution and tortuosity, which are input parameters for the models. The parallel pore model provides understanding of the occurring phenomena, but the input parameters were difficult to determine experimentally. The model predictions of intraparticle diffusion were of limited accuracy. We show that prediction can be improved when combining the model of Mackie and Meares with the fraction of accessible pore volume. The accessible pore volume fraction can be determined from inverse size exclusion chromatographic measurements. Future work should further challenge the improved model, specifically widening the applicability to greater accessible pore fractions (> 0.7) with corresponding higher intraparticle diffusivities (Dp/Dm > 0.2). A database of intraparticle diffusion and stationary phase pore property measurements is supplied, to contribute to general understanding of the relationship between intraparticle diffusion and pore properties.

    Circulaire systemen
    Bos, Harriëtte ; Groenestijn, John van; Harmsen, Paulien ; Hugenholtz, Jeroen ; Appelmans, Wilfred ; Jetten, Jan ; Bussmann, Pauil ; Bon, Jeroen van; Burgering, Maurits ; Verdoes, Nico ; Groenestein, Karin ; Duinkerken, Gert van; Fels-Klerx, Ine van der; Schans, Milou van de; Gerrits, Elise ; Schoumans, Oscar ; Haas, Wim de; Regelink, Inge ; Stuiver, Marian ; Bakker, Sjaak ; Dijk, Wim van; Visser, Saskia - \ 2019
    Wageningen : Wageningen University & Research - 41
    Recommended standards for conducting and reporting ethnopharmacological field studies
    Weckerle, Caroline S. ; Boer, Hugo J. de; Puri, Rajindra K. ; Andel, Tinde van; Bussmann, Rainer W. ; Leonti, Marco - \ 2018
    Journal of Ethnopharmacology 210 (2018). - ISSN 0378-8741 - p. 125 - 132.
    Ethnobotany - Ethnopharmacology - Field research - Methods - Standards - Traditional medicine

    Ethnopharmacological relevance What are the minimum methodological and conceptual requirements for an ethnopharmacological field study? How can the results of ethnopharmacological field studies be reported so that researchers with different backgrounds can draw on the results and develop new research questions and projects? And how should these field data be presented to get accepted in a scientific journal such as the Journal of Ethnopharmacology? The objective of this commentary is to create a reference that covers the basic standards necessary during planning, conducting and reporting of field research. Materials and methods We focus on conducting and reporting ethnopharmacological field studies on medicinal plants or materia medica and associated knowledge of a specific people or region. The article highlights the most frequent problems and pitfalls, and draws on published literature, fieldwork experience, and extensive insights from peer-review of field studies. Results Research needs to be ethical and legal, and follow local and national regulations. Primary ethnopharmacological field data need to be collected and presented in a transparent and comprehensible way. In short this includes: 1) Relevant and concise research questions, 2) Thorough literature study encompassing all available information on the study site from different disciplines, 3) Appropriate methods to answer the research questions, 4) Proper plant use documentation, unambiguously linked to voucher specimens, and 5) Qualitative and quantitative analyses of the collected data, the latter relying on use-reports as basic units. Conclusion Although not exhaustive, we provide an overview of the necessary main issues to consider for field research and data reporting including a list of minimal standards and recommendations for best practices. For methodological details and how to correctly apply specific methods, we refer to further reading of suggested textbooks and methods manuals.

    The counterintuitive role of extra-column volume in the determination of column efficiency and scaling of chromatographic processes
    Schultze-Jena, A. ; Boon, M.A. ; Bussmann, P.J.Th. ; Janssen, A.E.M. ; Padt, A. van der - \ 2017
    Journal of Chromatography. A, Including electrophoresis and other separation methods 1493 (2017). - ISSN 0021-9673 - p. 49 - 56.
    Dead volume - Extra-column contribution - Industrial chromatography - Separation performance

    In industrial liquid separation processes chromatography often has a key function in the optimization of yield and purity. For the design of an industrial system, chromatographic processes are generally simulated using mathematical models, tested and optimized at laboratory level, and then scaled up to pilot and subsequently industrial scale. To describe the system, experimental data and model data need to be fitted and extra column contribution must be determined. This paper describes the influence of extra-column volume on overall separation efficiency for lab scale and its impact on the design of large scale systems.Measurement of extra-column contribution was investigated in terms of mean retention time and variance using two different methods the commonly used zero dead volume connector and as an alternative the zero length column. Further a technique is presented to estimate extra-column contribution to band broadening for different injection volumes, velocities, and tracers based on representative measurements.When scaling up, often contribution of extra-column volume from laboratory equipment is neglected assuming to be on the safe side, however column efficiency is often lower than efficiency measured for the entire chromatographic system. Relation between system efficiency and column efficiency was investigated using laboratory data and the lumped kinetic model. Depending on the ratio of extra-column volume to retention volume in the system, deduced column efficiency was up to 20% smaller than overall system efficiency. This ratio revealed the misleading nature of the term efficiency loss, when describing influence of extra-column volume on column efficiency. A scheme, which relates the relative variance of the system to the relative extra-column volume, provided an assessment of under- or overestimation of column efficiency. In this article it is shown how scaling up a system based on laboratory data, where extra-column volume contribution is not accounted for, may severely overestimate column efficiency. This overestimation results in underestimated column dimensions at pilot and industrial scale, and hence underperformance of the industrial system.

    The role of extra-column volume in column efficiency and upscaling
    Schultze-Jena, A.S.C. ; Boon, M.A. ; Bussmann, P.J.Th. ; Janssen, A.E.M. ; Padt, A. van der - \ 2016
    •Column efficiency is higher when extra-column volume is not taken into account
    •Column dimensions could be up to 20% underestimated
    •The term efficiency loss is misleading in preparative chromatography
    Traditional medicine
    Payyappallimana, U. ; Subramanian, M. ; Timoshyna, A. ; Graz, B. ; Leaman, D. ; Bussmann, R.W. ; Hariramamurthi, G. ; Shankar, D. ; Klooster, C.I.E.A. van 't; Bodeker, G. ; Sekagya, Y. ; Hemstra, W. ; Gomez, F. ; Verschuuren, B. ; Ravin, E. de; Ligare, J. ; Reid, A.M. ; Petersen, L.M. - \ 2015
    In: Connecting Global Priorities: Biodiversity and Human Health World Health Organization - ISBN 9789241508537 - p. 180 - 199.
    Entpd5 is essential for skeletal mineralization and regulates phosphate homeostasis in zebrafish (online)
    Huitema, L.F.A. ; Apschner, A. ; Logister, I. ; Spoorendonk, K.M. ; Bussmann, J. ; Hammond, C.L. ; Schulte-Merker, S. - \ 2012
    Proceedings of the National Academy of Sciences of the United States of America 109 (2012)52. - ISSN 0027-8424 - p. 21372 - 21377.
    bone - model - osteoblasts - expression - calcification - members - cd39l4 - family - genes - acid
    Bone mineralization is an essential step during the embryonic development of vertebrates, and bone serves vital functions in human physiology. To systematically identify unique gene functions essential for osteogenesis, we performed a forward genetic screen in zebrafish and isolated a mutant, no bone (nob), that does not form any mineralized bone. Positional cloning of nob identified the causative gene to encode ectonucleoside triphosphate/diphosphohydrolase 5 (entpd5); analysis of its expression pattern demonstrates that entpd5 is specifically expressed in osteoblasts. An additional mutant, dragonfish (dgf), exhibits ectopic mineralization in the craniofacial and axial skeleton and encodes a loss-of-function allele of ectonucleotide pyrophosphatase phosphodiesterase 1 (enpp1). Intriguingly, generation of double-mutant nob/dgf embryos restored skeletal mineralization in nob mutants, indicating that mechanistically, Entpd5 and Enpp1 act as reciprocal regulators of phosphate/pyrophosphate homeostasis in vivo. Consistent with this, entpd5 mutant embryos can be rescued by high levels of inorganic phosphate, and phosphate-regulating factors, such as fgf23 and npt2a, are significantly affected in entpd5 mutant embryos. Our study demonstrates that Entpd5 represents a previously unappreciated essential player in phosphate homeostasis and skeletal mineralization.
    Zeolites for reducing drying energy usage
    Boxtel, A.J.B. van; Boon, M.A. ; Deventer, H. van; Bussmann, P.J.T. - \ 2012
    In: Modern Drying Technology / Tsotsas, E., Mujumdar, A.S., Weinhem, Germany : Wiley-VCH Verlag GmbH & Co. KGaA (Energy Savings 4) - ISBN 9783527315598 - p. 163 - 197.
    Rapid BAC selection for tol2-mediated transgenesis in zebrafish
    Bussmann, J. ; Schulte-Merker, S. - \ 2011
    Development 138 (2011)19. - ISSN 0950-1991 - p. 4327 - 4332.
    bacterial artificial chromosomes - fluorescent protein - expression - embryos - gene - integration - circuits - tol2 - mice
    The generation of zebrafish transgenic lines that express specific fluorophores in a cell-or tissue-specific manner is an important technique that takes full advantage of the optical clarity of the embryo. Identifying promoter fragments that faithfully recapitulate endogenous expression patterns and levels is often difficult and using large genomic DNA fragments, such as bacterial artificial chromosomes (BACs), makes the process of transgenesis less reliable. Here we provide a detailed protocol that allows for BAC selection and subsequent rapid modification through recombineering in Escherichia coli, resulting in BACs that can be injected into zebrafish embryos and, aided by tol2-mediated transgenesis, reliably yield stable transgenic lines. A number of BACs can be prepared in parallel, and injection of the BACs containing CFP/YFP/RFP or Gal4 cassettes allows for immediate testing of whether a particular BAC will yield the desired result. Furthermore, since injected embryos often show widespread expression, recombineered BACs provide an alternative to two-color in situ hybridizations: BACs injected into embryos of a different transgenic reporter line thus enable in vivo colocalization studies. Using this protocol, we have generated 66 stable lines for 23 different genes, with an average transgenesis rate above 10%. Importantly, we provide evidence that BAC size shows no apparent correlation to the transgenesis rate achieved and that there are no severe position effects.
    Landsliding and its multiscale influence on mountainscapes
    Restrepo, C. ; Walker, L.R. ; Bussmann, R. ; Claessens, L. - \ 2009
    Bioscience 59 (2009)8. - ISSN 0006-3568 - p. 685 - 698.
    puerto-rican landslides - british-columbia - new-zealand - land-cover - vegetation - forest - soil - disturbance - succession - recovery
    Landsliding is a complex process that modifies mountainscapes worldwide. Its severe and sometimes long-lasting negative effects contrast with the less-documented positive effects on ecosystems, raising numerous questions about the dual role of landsliding, the feedbacks between biotic and geomorphic processes, and, ultimately, the ecological and evolutionary responses of organisms. We present a conceptual model in which feedbacks between biotic and geomorphic processes, landslides, and ecosystem attributes are hypothesized to drive the dynamics of mountain ecosystems at multiple scales. This model is used to integrate and synthesize a rich, but fragmented, body of literature generated in different disciplines, and to highlight the need for profitable collaborations between biologists and geoscientists. Such efforts should help identify attributes that contribute to the resilience of mountain ecosystems, and also should help in conservation, restoration, and hazard assessment. Given the sensitivity of mountains to land-use and global climate change, these endeavors are both relevant and timely
    Granular mixing and segregation in a horizontal rotating drum: a simulation study on the impact of rotational speed and fill level
    Arntz, M.M.H.D. ; Otter, W.K. den; Briels, W.J. ; Bussmann, P.J.T. ; Beeftink, H.H. ; Boom, R.M. - \ 2008
    AIChE Journal 54 (2008)12. - ISSN 0001-1541 - p. 3133 - 3146.
    size segregation - radial segregation - transverse plane - rotary kilns - flow - cylinders - solids - particles - dynamics - model
    The rich phase behavior of granular beds of bidisperse hard spherical particles in a rotating horizontal drum is studied by Discrete Element Method (DEM) simulations. Several flow regimes and various forms of radial segregation, as well as mixing, are observed by systematically varying the operational parameters of the drum, i.e. fill level and angular velocity, over a wide range. Steady states after several dozen revolutions are summarized in two bed behavior diagrams, showing strong correlations between flow regime and segregation pattern. An entropy method quantifies the overall degree of mixing, while density and velocity plots are used to analyze the local properties of the granular bed. The percolation mechanism may provide a qualitative explanation for the distinct segregation processes, and for the transient mixing in nonradially segregated beds. Initially blockwise segregated beds are found to mix before radial segregation sets in. High fill fractions (>65%) show the most intense segregation
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