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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De boer op de tractor wordt mogelijk verleden tijd
Veldhuisen, Bram - \ 2019
The diurnal transcriptional landscape of the microalga Tetradesmus obliquus
Carreres, Benoit M. ; Mitsue León-Saiki, G. ; Schaap, Peter J. ; Remmers, Ilse M. ; Veen, Douwe van der; Martins dos Santos, Vitor A.P. ; Wijffels, René H. ; Martens, Dirk E. ; Suarez-Diez, Maria - \ 2019
Algal Research 40 (2019). - ISSN 2211-9264
Day/night cycles - Diurnal transcription changes - Microalgae - Photosynthetic efficiency - Scenedesmus obliquus - starchless mutant

Tetradesmus obliquus is a promising oleaginous microalga. We functionally annotated its genome and characterized the transcriptional landscape of T. obliquus adapted to 16:8 h light dark (LD) cycles in turbidostat culture conditions at very high temporal resolution (1 h intervals). Revealing a cycle of cellular events, six distinct expression profiles were obtained, each with transcriptional phenotypes correlating with measurements of biochemical composition. The impact of starch deficiency was studied using the starchless mutant slm1. Significant changes in the transcriptional landscape were observed. Starch deficiency resulted in incapacity to supply energy during the dark period, resulting in a shift of energy demanding processes to an earlier or later time point. Our study provides new perspectives on the role of starch and the adaptation to LD cycles of oleaginous microalgae.

Influence of Cell Configuration and Long-Term Operation on Electrochemical Phosphorus Recovery from Domestic Wastewater
Lei, Yang ; Remmers, Jorrit Christiaan ; Saakes, Michel ; Weijden, Renata D. Van Der; Buisman, Cees J.N. - \ 2019
ACS sustainable chemistry & engineering 7 (2019)7. - ISSN 2168-0485 - p. 7362 - 7368.
Calcium phosphate - Current density - Electrode distance - Energy consumption - Local high pH

Phosphorus (P) is an important, scarce, and irreplaceable element, and therefore its recovery and recycling are essential for the sustainability of the modern world. We previously demonstrated the possibility of P recovery by electrochemically induced calcium phosphate precipitation. In this Article, we further investigated the influence of cell configuration and long-term operation on the removal of P and coremoved calcium (Ca), magnesium (Mg), and inorganic carbon. The results indicated that the relative removal of P was faster than that of Ca, Mg, and inorganic carbon initially, but later, due to decreased P concentration, the removal of Ca and Mg became dominant. A maximum P removal in 4 days is 75% at 1.4 A m -2 , 85% at 8.3 A m -2 and 92% at 27.8 A m -2 . While a higher current density improves the removal of all ions, the relative increased removal of Ca and Mg affects the product quality. While the variation of electrode distance and electrode material have no significant effects on P removal, it has implication for reducing the energy cost. A 16-day continuous-flow test proved calcium phosphate precipitation could continue for 6 days without losing efficiency even when the cathode was covered with precipitates. However, after 6 days, the precipitates need to be collected; otherwise, the removal efficiency dropped for P removal. Economic evaluation indicates that the recovery cost lies in the range of 2.3-201.4 euro/kg P, depending on P concentration in targeted wastewater and electrolysis current. We concluded that a better strategy for producing a product with high P content in an energy-efficient way is to construct the electrochemical cell with cheaper stainless steel cathode, with a shorter electrode distance, and that targets P-rich wastewater.

Is There a Precipitation Sequence in Municipal Wastewater Induced by Electrolysis?
Lei, Yang ; Remmers, Jorrit Christiaan ; Saakes, Michel ; Weijden, Renata D. van der; Buisman, Cees J.N. - \ 2018
Environmental Science and Technology 52 (2018)15. - ISSN 0013-936X - p. 8399 - 8407.

Electrochemical wastewater treatment can induce calcium phosphate precipitation on the cathode surface. This provides a simple yet efficient way for extracting phosphorus from municipal wastewater without dosing chemicals. However, the precipitation of amorphous calcium phosphate (ACP) is accompanied by the precipitation of calcite (CaCO3) and brucite (Mg(OH)2). To increase the content of ACP in the products, it is essential to understand the precipitation sequence of ACP, calcite, and brucite in electrochemical wastewater treatment. Given the fact that calcium phosphate (i.e., hydroxyapatite) has the lowest thermodynamic solubility product and highest saturation index in the wastewater, it has the potential to precipitate first. However, this is not observed in electrochemical phosphate recovery from raw wastewater, which is probably because of the very high Ca/P molar ratio (7.5) and high bicarbonate concentration in the wastewater resulting in formation of calcite. In the case of decreased Ca/P molar ratio (1.77) by spiking external phosphate, most of the removed Ca in the wastewater was used for ACP formation instead of calcite. The formation of of brucite, however, was only affected when the current density was decreased or the size of cathode was changed. Overall, the removal of Ca and Mg is much more affected by current density than the surface area of cathode, whereas for P removal, the reverse is true. Because of these dependencies, though there is no definite precipitation sequence among ACP, calcite, and brucite, it is still possible to influence the precipitation degree of these species by relatively low current density and high surface area or by targeting phosphorus-rich wastewaters.

Orchestration of transcriptome, proteome and metabolome in the diatom Phaeodactylum tricornutum during nitrogen limitation
Remmers, Ilse M. ; Adamo, Sarah D'; Martens, Dirk E. ; Vos, Ric C.H. de; Mumm, Roland ; America, Antoine H.P. ; Cordewener, Jan H.G. ; Bakker, Linda V. ; Peters, Sander A. ; Wijffels, René H. ; Lamers, Packo P. - \ 2018
Algal Research 35 (2018). - ISSN 2211-9264 - p. 33 - 49.
Diatoms - Diurnal metabolism - Lipids - Mitochondrion - Omics - Triacylglycerol

Nitrogen deprivation increases the triacylglycerol (TAG) content in microalgae but also severely decreases the growth rate. Most approaches that attempted to increase TAG productivity by overexpression or knockdown of specific genes related to the regulation of the lipid synthesis have reported only little success. More insight into the molecular mechanisms related to lipid accumulation and impaired growth rate is needed to find targets for improving TAG productivity. By using the emerging “omics” approach, we comprehensively profiled the physiology, transcriptome, proteome and metabolome of the diatom Phaeodactylum tricornutum during steady state growth at both nitrogen limited and replete levels during light:dark cycles. Under nitrogen limited conditions, 22% (2699) of the total identified transcripts, 17% (543) of the proteins and 44% (345) of the metabolites were significantly differentially regulated compared to nitrogen replete growth conditions. Although nitrogen limitation was responsible for the majority of significant differential transcript, protein and metabolite accumulation, we also observed differential expression over a diurnal cycle. Nitrogen limitation mainly induced an upregulation of nitrogen fixation, central carbon metabolism and TCA cycle, while photosynthetic and ribosomal protein synthesis are mainly downregulated. Regulation of the lipid metabolism and the expression of predicted proteins involved in lipid processes suggest that lipid rearrangements may substantially contribute to TAG distribution. However, TAG synthesis is also limited by the reduced carbon flux through central metabolism. Future strain improvements should therefore focus on understanding and improving the carbon flux through central carbon metabolism, selectivity and activity of DGAT isoforms and lipase enzymes.

Can We Approach Theoretical Lipid Yields in Microalgae?
Remmers, Ilse M. ; Wijffels, René H. ; Barbosa, Maria J. ; Lamers, Packo P. - \ 2018
Trends in Biotechnology 36 (2018)3. - ISSN 0167-7799 - p. 265 - 276.
Cultivation strategies - Metabolism - Microalgae - Outdoor production - Strain improvement - Triacylglycerol (TAG)
Can we approach theoretical lipid yields in microalgae? Yes: we can substantially reduce the gap between current and theoretical maximum yield. A realistic maximum is approximately 0.5. g triacylglycerol (TAG) per mol photons, about five times higher than what is currently achieved in outdoor cultivation. Achieving this realistic maximum will require several breakthroughs. First, outdoor operation typically has low yields, mainly caused by fluctuating insolation. Future adaptive control models will help increase these yields. Additionally, the lipid production capacity of currently used strains needs to increase. Powerful strain-specific molecular toolboxes are being developed, shifting the bottleneck towards understanding metabolism and identifying target genes. Finally, strains and processes should be improved concurrently to fully exploit the potential lipid production from microalgae. To fulfill the necessity for improved yields in microalgal lipid production, current research is moving towards advanced cultivation strategies, including adaptation to fluctuating outdoor weather conditions.Recent developments of targeted gene-editing technology (e.g., CRISPR/Cas9) and improved high-throughput screening techniques in microalgae contribute to fast and automatized strain improvement approaches.Industrial needs and higher oil productivities of microalgae compared with plants will foster the development of tailored microalgal oils.
Photosynthetic efficiency in microalgal lipid production
Remmers, Ilse M. - \ 2017
Wageningen University. Promotor(en): R.H. Wijffels, co-promotor(en): P.P. Lamers. - Wageningen : Wageningen University - ISBN 9789463434607 - 200
algae - biofuels - light - triacylglycerols - lipids - metabolism - algae culture - cultural methods - algen - biobrandstoffen - licht - triacylglycerolen - lipiden - metabolisme - algenteelt - cultuurmethoden

Microalgae can contain large amounts of lipids which make them a promising feedstock for sustainable production of food, feed, fuels and chemicals. Various studies, including pilot-scale, have been performed and the knowledge on microalgal processes has advanced quickly. Unfortunately, current production costs for cultivation are still too high for bulk lipid production from microalgae.

One of the major causes for the high costs of bulk lipid production is the reduced solar-to-lipid conversion efficiency. Current research, however, does not provide sufficient insight to identify optimization targets. Therefore, in this thesis we have studied the lipid production in microalgae in depth.

Different TAG-accumulation strategies were investigated from a process engineering and metabolic point of view. The combination of all findings were used in the general discussion to thoroughly evaluate the microalgal lipid accumulation strategies. Current phototrophic microalgal lipid yields are still 10 times lower than the theoretical maximum. There is, however, still an enormous potential for further improvements. Future research should focus on (genetically) improved strains and advanced cultivation strategies, including adaptation to fluctuating outdoor weather conditions.

This thesis was performed within the EU FP7 FUEL4ME project under grand agreement No 308938. Objective of this program is to develop a sustainable and scalable process for biofuels from microalgae and to valorize the by-products.

The role of starch as transient energy buffer in synchronized microalgal growth in Acutodesmus obliquus
Leon Saiki, Mitsue ; Remmers, Ilse M. ; Martens, Dirk E. ; Lamers, Packo P. ; Wijffels, René H. ; Veen, Douwe van der - \ 2017
Algal Research 25 (2017). - ISSN 2211-9264 - p. 160 - 167.
Day/night cycles - Diurnal biochemical changes - Microalgae - Photosynthetic efficiency - Scenedesmus obliquus - Starchless mutant

Photosynthetic organisms have evolved to use light efficiently by scheduling their cellular processes, such as growth and cell division, at specific times of the day. During the day, fixed carbon is used for growth and is partially stored as carbohydrates (e.g., starch). It is commonly assumed that this accumulated starch is essential for fuelling up cell division at night. To test this hypothesis, this study investigates growth, cell division and presence of a transitory energy storage (TES) in both the wild-type and starchless mutant strain of Acutodesmus obliquus under light/dark (LD) cycles and nitrogen replete conditions. A. obliquus (formerly known as Scenedesmus obliquus) wild-type utilized light 20% more efficiently under LD regimes compared with continuous light. When exposed to LD regimes, the wild-type scheduled cell division in a 4-hour period starting 2 h before ‘sunset’. Starch acted as the major transitory energy storage (TES) compound: it was accumulated during the last part of the light period and was consumed throughout the entire dark period. The slm1 mutant, with a blocked starch synthesis pathway, showed diurnal rhythms in growth and cell division. However, no other carbohydrates nor triacylglycerols took over the role of TES compound in slm1. Therefore, in contrast to what is generally acknowledged, this study shows that neither starch nor any other major alternative TES is required for synchronized growth and cell division in A. obliquus. The starchless mutant did show a reduced growth and cell division rate compared to the wild-type. Starch, thus, plays a major role in efficient harnessing of light energy over LD cycles, likely because the ability to accumulate starch enhances biomass production capacity and accelerates cell division rate in A. obliquus.

Continuous versus batch production of lipids in the microalgae Acutodesmus obliquus
Remmers, I.M. ; Hidalgo-Ulloa, A. ; Brandt, B.P. ; Evers, W.A.C. ; Wijffels, R.H. ; Lamers, P.P. - \ 2017
Bioresource Technology 244 (2017). - ISSN 0960-8524 - p. 1384 - 1392.
Diurnal LD cycles - Microalgae - Scenedesmus obliquus - Starch - Triacylglycerol (TAG)
This work provides a novel quantitative comparison of batch versus continuous microalgal lipid production in the wild type and starchless mutant strain of Acutodesmus obliquus. Both strains showed higher TAG yields on light under batch operation compared to continuous nitrogen limitation. The starchless mutant showed 0.20gTAGmolph -1 for batch and 0.12gTAGmolph -1 for continuous operation, while the wildtype only showed 0.16gTAGmolph -1 for batch and 0.08gTAGmolph -1 for continuous operation. Also, higher TAG contents were found under batch starvation (26% of dry weight for the wildtype and 43% of dry weight for starchless mutant) compared to continuous cultivations (16% of dry weight for the wildtype and 33% of dry weight for starchless mutant). Starch acts as the favoured storage metabolite during nitrogen limitation in A. obliquus, whereas TAG is only accumulated after starch reaches a cellular maximum of 40% of dry weight.
Dynamics of triacylglycerol and EPA production in Phaeodactylum tricornutum under nitrogen starvation at different light intensities
Remmers, Ilse M. ; Martens, Dirk E. ; Wijffels, René H. ; Lamers, Packo P. - \ 2017
PLoS ONE 12 (2017)4. - ISSN 1932-6203

Lipid production in microalgae is highly dependent on the applied light intensity. However, for the EPA producing model-diatom Phaeodactylum tricornutum, clear consensus on the impact of incident light intensity on lipid productivity is still lacking. This study quantifies the impact of different incident light intensities on the biomass, TAG and EPA yield on light in nitrogen starved batch cultures of P. tricornutum. The maximum biomass concentration and maximum TAG and EPA contents were found to be independent of the applied light intensity. The lipid yield on light was reduced at elevated light intensities (>100 μmol m-2 s-1). The highest TAG yield on light (112 mg TAG molph -1) was found at the lowest light intensity tested (60 μmol m-2 s-1), which is still relatively low to values reported in literature for other algae. Furthermore, mass balance analysis showed that the EPA fraction in TAG may originate from photosynthetic membrane lipids.

Continuous versus batch production of microalgal lipids
Remmers, Ilse - \ 2016
Development of a lactic acid production process using lignocellulosic biomass as feedstock
Pol, E.C. van der - \ 2016
Wageningen University. Promotor(en): Gerrit Eggink, co-promotor(en): Ruud Weusthuis. - Wageningen : s.n. - ISBN 9789462576735 - 167
lignocellulose - biomass - biobased chemicals - sugarcane bagasse - lactic acid - sugars - byproducts - inhibitors - pretreatment - bacillus coagulans - furfural - saccharification - fermentation - quantitative techniques - production processes - lignocellulose - biomassa - chemicaliën uit biologische grondstoffen - suikerrietbagasse - melkzuur - suikers - bijproducten - remmers - voorbehandeling - bacillus coagulans - furfural - versuikering - fermentatie - kwantitatieve technieken - productieprocessen

The availability of crude oil is finite. Therefore, an alternative feedstock has to be found for the production of fuels and plastics. Lignocellulose is such an alternative feedstock. It is present in large quantities in agricultural waste material such as sugarcane bagasse.

In this PhD thesis, lignocellulose is chemically and enzymatically pretreated to depolymerise sugars present in this structure. The released sugar monomers are fermented by micro-organisms to lactic acid, which is a precursor for the bioplastic PLA. In this thesis, it is shown that it is possible to produce lactic acid from lignocellulosic biomass with high yields and high productivities.

Lipid production in Phaeodactylum tricornutum
Remmers, Ilse - \ 2014
Lipid production in Phaeodactylum tricornutum
Remmers, Ilse - \ 2014
Lipid production in Phaeodactylum tricornutum
Remmers, Ilse - \ 2014
GM1-derived carbohydrates for pathogen and antibody detection : synthesis and biological evaluation
Garcia Hartjes, J. - \ 2014
Wageningen University. Promotor(en): Han Zuilhof, co-promotor(en): Tom Wennekes. - Wageningen : Wageningen University - ISBN 9789462571273 - 240
koolhydraten - moleculaire detectie - antilichamen - pathogenen - remmers - biotesten - carbohydrates - molecular detection - antibodies - pathogens - inhibitors - bioassays
Growing Green Cities: an Emerging Strategy for Sustainable Regional Food Planning in the Amsterdam Metropolitan Area
Valk, A.J.J. van der; Remmers, G. - \ 2013
In: Book of Abstracts, Innovations in Urban Food Systems, Montpellier, France, 28-29 October 2013. - Montpellier : - p. 102 - 102.
Algen voor de productie van voeding, biobrandstoffen en chemicalien
Remmers, Ilse - \ 2012
Het hangt in de lucht!
Derkzen, P.H.M. ; Coenders, S. - \ 2009
In: Bezieling. De x-factor in gebiedsontwikkeling / Horlings, I., Remmers, G., Duffues, T., Tilburg : Telos - ISBN 9789077572054 - p. 112 - 121.
Pleidooi voor constructieve interactie
Aarts, N. - \ 2007
In: De Innerlijke Ruimte van de Nederlandse delta. Werkboek voor een nieuwe ruimtelijke inrichting / Remmers, G., Utrecht : InnovatieNetwerk - ISBN 9789050593212 - p. 54 - 62.
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