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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    Outdoor production of microalgae
    Vree, Jeroen H. de - \ 2016
    Wageningen University. Promotor(en): Rene Wijffels, co-promotor(en): Rouke Bosma; Maria Barbosa. - Wageningen : Wageningen University - ISBN 9789462578784 - 179
    algae - algae culture - design - bioreactors - photobioreactors - modeling - algen - algenteelt - ontwerp - bioreactoren - fotobioreactoren - modelleren

    This thesis describes the production of microalgae under outdoor conditions, for this research was done at pilot scale. Microalgae are an interesting alternative to currently used sources for bulk commodities as food, feed and chemicals. Research activities within the field are shattered; different reactor systems are investigated at different locations while the systems are operated with different species. The shattered activities prevent a consensus to be reached within the scientific community on the reactor system that has the best performance. Selecting the best performing reactor system will bring the algae industry to the next level. In this PhD thesis different reactor designs were compared on a single location while using the same species in all systems. For this purpose the microalgal pilot facility AlgaePARC (Production And Research Centre) was designed and is described within this thesis. Followed by a comparison of the different reactor designs while using for each comparison a different operational strategy. Operational strategies investigated were chemostat operation and turbidostat operation. During chemostat operation a fixed daily dilution rate is applied to the reactor system, biomass concentrations vary as a result of the applied dilution rate and light conditions. During turbidostat operation the biomass concentration within a system is fixed and as a result of the set biomass concentration and light conditions the daily dilution rate varies. Findings from laboratory scale to pilot scale experiments are extrapolated to indicate the potential of microalgae production at a commercial scale. For these extrapolations mathematical models should be used, which require microalgae species specific input parameters. In this thesis input parameters for two industrially relevant microalgae species were obtained and reported. Finally a techno-economic evaluation was developed to indicate the potential of microalgae as a bulk commodity and to pinpoint focal points for future research.

    Antenna size reduction in microalgae mass culture
    Mooij, T. de - \ 2016
    Wageningen University. Promotor(en): Rene Wijffels, co-promotor(en): Marcel Janssen. - Wageningen : Wageningen University - ISBN 9789462578890 - 196
    algae culture - algae - light - photobioreactors - photosynthesis - mutants - algenteelt - algen - licht - fotobioreactoren - fotosynthese - mutanten

    The thesis describes the potential of microalgae with a reduced light harvesting antenna for biomass production under mass culture conditions (high biomass density, high light intensity). Theoretically, the lower chlorophyll content reduces the light harvesting capacity and with that the amount of photosaturation. The result would be an increase of the biomass yield on light energy, which is especially favorable at high light intensities. In practice, it was found that the productivity of several antenna size mutants strains was equal, or even lower than that of wild type microalgae. The genetically modified algae suffered from a reduced fitness, possibly because the antenna alterations led to impaired photoprotection mechanisms. In an alternative approach, it was found that by spectral tuning (applying different light colours) oversaturation was decreased and the productivity of wild type microalgae was increased. Special attention was paid to photoacclimation behavior of wild type microalgae. It was investigated whether ‘natural acclimation’ can be exploited to maximize productivity. In the last chapter, the competition between antenna size mutants and wild type cells is investigated by means of a modeling approach. It became clear that a wild type infection of an antenna size mutant culture should be prevented at all costs, as the mutants have a reduced competitive strength.

    Microalgae for aquaculture
    Michels, M.H.A. - \ 2015
    Wageningen University. Promotor(en): Rene Wijffels, co-promotor(en): Marian Vermue. - Wageningen : Wageningen University - ISBN 9789462572249
    aquacultuur - aquacultuursystemen - algenteelt - visvoeding - fotobioreactoren - biomassa productie - biobased economy - aquaculture - aquaculture systems - algae culture - fish feeding - photobioreactors - biomass production - biobased economy
    In 2007, the project ‘Zeeuwse Tong’ (Zeeland Sole) was founded with support of the province of Zeeland, the Netherlands. The aim of the Zeeuwse Tong project was to establish an innovative land-based integrated multi-trophic aquaculture sector, which is producing sole, ragworms, algae, shellfish and saline crops in close harmony with nature. The project was divided into two sub-projects: The integrated saline aquaculture farm and the integrated nursery. The research described in this thesis resides within the integrated nursery subproject. In this project the rearing of fingerlings of sole would be combined with the cultivation of microalgae as feed for shellfish larvae and spat inside a greenhouse. An integrated nursery in a greenhouse has several advantages: a greenhouse with a multipurpose use of space, sole culture combined with the cultivation of microalgae and shellfish larvae or spat, an integrated thermoregulation and the reuse of nutrients from the wastewater of the fish basins for the production of microalgae in closed photobioreactors (PBRs). For this thesis, a horizontal tubular PBR needed to be designed and constructed to investigate the productivity and yield of microalgae applied as feed for shellfish larvae or spat, within the context of an integrated nursery.
    Microalgae cultivation for nutrient recovery from human urine
    Tuantet, K. - \ 2015
    Wageningen University. Promotor(en): Grietje Zeeman, co-promotor(en): Hardy Temmink; Marcel Janssen. - Wageningen : Wageningen University - ISBN 9789462572676 - 174
    afvalwaterbehandeling - afvalwateraquacultuur - urine - algenteelt - terugwinning - fosfor - stikstof - fotobioreactoren - biomassa productie - biobased economy - nieuwe sanitatie - waste water treatment - wastewater aquaculture - urine - algae culture - recovery - phosphorus - nitrogen - photobioreactors - biomass production - biobased economy - new sanitation
    Nieuwe, brongerichte sanitatieconcepten krijgen meer en meer aandacht en laten een groot potentieel zien voor het terugwinnen van nutriënten, organische stof en water, en voor de productie van energie. Verschillende van deze nieuwe sanitatieconcepten zijn geïmplementeerd in landen zoals Nederland, Duitsland, Zweden en China. Van de beschikbare terugwinningstechnieken voor urine is er geen één die zowel stikstof als fosfor kan terugwinnen. Dat is wel mogelijk door algen te kweken op urine, vanwege de hoge N:P ratio in de algen biomassa. Tot nu toe zijn er maar een beperkt aantal studies uitgevoerd gericht op het gebruik van urine voor het kweken van microalgen. Microalgenkweek heeft een groot potentieel voor de behandeling van urine in vergelijking met de meeste andere technieken die op dit moment al commercieel beschikbaar zijn. Een model system voor Nederlandse omstandigheden werd geëvalueerd, gebruik makend van parameterwaarden uit de experimenten beschreven in dit proefschrift als wel uit de literatuur. Dit heeft aangetoond dat in Nederland microalgenkweek mogelijk is van de late lente tot laat in de zomer.
    Scenario studies for algae production
    Slegers, P.M. - \ 2014
    Wageningen University. Promotor(en): Gerrit van Straten; Rene Wijffels, co-promotor(en): Ton van Boxtel. - Wageningen : Wageningen University - ISBN 9789461738448 - 221
    algen - algenteelt - ontwerp - fotobioreactoren - plassen - biomassa productie - biomassa - energiegebruik - bioproceskunde - algae - algae culture - design - photobioreactors - ponds - biomass production - biomass - energy consumption - bioprocess engineering

    Microalgae are a promising biomass for the biobased economy to produce food, feed, fuel, chemicals and materials. So far, large-scale production of algae is limited and as a result estimates on the performance of such large systems are scarce. There is a need to estimate large-scale biomass productivity and energy consumption, while considering the uncertainty and complexity in such large-scale systems.

    In this thesis frameworks are developed to assess 1) the productivity during algae cultivation, 2) energy consumption during the transport of resources and processing biomass to biodiesel, and 3) the frameworks are applied to estimate the impact of algae cultivation in the production of algae-based food commodities. Design, location and future scenario are applied to deal with the complexity and uncertainty arising in the various data and models used.

    The first part of this thesis focuses on the development of a productivity framework for biomass production for flat panels (Chapter 2), horizontal and vertical tubular photobioreactors (Chapter 3) and raceway ponds (Chapter 4). The framework uses bio-physics-based models to simulate the light input on the reactor surface and the light gradient inside the reactor systems. The internal light gradient depends on the reactor geometry and dimensions, and the penetration of diffuse light between parallel reactors, which includes the canyon effect, and the reflection of light from the ground surface to the reactors are incorporated as well. Specific growth rates are derived from this internal light gradient based on species-specific growth characteristics. In raceway ponds the effect of the dynamic water temperature on the specific growth rate is included.

    The productivity framework enables to study cultivation under a wide range of process conditions and reactor designs, even those which have not been yet developed or tested under outdoor conditions. The results show that regional weather conditions, solar angles and algae species are key factors in making the best choice for the specific reactor design. The productivity framework allows to optimise the reactor design (e.g. geometry, light path, distances between parallel units and height) to the regional light conditions and growth characteristics of the algae species of interest. The best biomass concentration for cultivation varies between the reactor design, location and algae species. We recommend to select species suited to growth well at the regional light angles and weather conditions. An initial global sensitivity analysis shows that the absorption coefficient, maximum specific growth rate and functional cross section of the photosynthetic apparatus are the essential parameters of the model for single flat panels. An important next step is to validate and calibrate the productivity framework using data from outdoor experiments in various reactor designs, at different locations and with several algae species.

    Algae production is strongly connected to regional weather conditions, but also to the infrastructure for resource supply and to the processing of biomass. The energy consumption for resource supply has not been quantified yet and the energy consumption of biomass processing is mostly based on fixed values. These elements are tackled in part 2 of this thesis.

    In Chapter 5the productivity framework is combined with logistic models to optimise the supply network for algae cultivation. The results show that the availability, supply and demand of resources has a dominant effect on the feasibility of regions for algae cultivation. Not all locations achieve a positive energy balance for transport and the supply logistics is essential for planning algae cultivation locations. In the Benelux many locations are feasible for algae production due to the availability of large amounts of resources, while the limited supply of CO2in southern France and the Sahara demands for plants which are scattered over the regions. For the Sahara the distance for water transport should be minimal. Still, the average transport distances are higher than commonly assumed and algae cultivation does not necessarily need to take place in proximity of CO2supply. The transport energy consumption is found to be low compared to the energy contained in algae biomass (mostly below 3%).

    Chapter 6 describesa model-based combinatorial optimisation approach for the energy-efficientprocessing of algae biomass. In this approach, mass and energy balances and additional relations are used to relate the product yield and energy consumption of process units and process routes to the processing conditions. Process routes with the highest net energy ratios are derived by optimising the process conditions of each process unit in a given superstructure. This optimisation leads to 5-38% improvement of the net energy ratio compared to fixed process conditions. The approach moreover allows a bottleneck analysis for each process route. The results show that process design should be tailor-made. The model-based approach proves to be a versatile tool for the design of efficient microalgae processing systems.

    The developed frameworks combined with scenario studies are a powerful tool to assess algae production. The presented approaches help to reduce the uncertainty in the interpretation of data and are thereby an appropriate basis to use in impact analysis. In Chapter 7this is illustrated for the production of algae protein and oil as food commodities. The design scenarios show the implications of various reactor designs, two algae species and at two locations on biomass productivity, production cost and environmental life cycle indicators.

    The achievements of this work and the new horizons from this work are discussed in Chapter 8. The results of the developed frameworks demonstrate the power of the scenario approach and show that sensible predictions and projections of biomass productivity and energy consumption for logistics and biomass processing follow from the models.

    Algenteelt in fotobioreactoren in kas in Bleiswijk: ervaringen na een jaar
    Voogt, W. ; Hemming, S. ; Sapounas, A. ; Scheffers, C.P. ; Winkel, A. van - \ 2013
    teeltsystemen - algenteelt - algen - fotobioreactoren - proeven op proefstations - glastuinbouw - biobased economy - cropping systems - algae culture - algae - photobioreactors - station tests - greenhouse horticulture - biobased economy
    Poster met onderzoeksinfgormatie. Doel van dit onderzoek is het leren telen van algen in een kas, verzamelen van meetgegevens en kengetallen en ervaring opdoen met het effect van groeifactoren op de groei en ontwikkeling van algen.
    Effects of oxygen concentration on the growth of Nannochloropsis sp.
    Raso, S. - \ 2013
    Wageningen University. Promotor(en): Rene Wijffels, co-promotor(en): Marian Vermue. - S.l. : s.n. - ISBN 9789461737472 - 157
    algen - voer - aquacultuur - visvoeding - fotobioreactoren - eicosapentaeenzuur - zuurstof - algae - feeds - aquaculture - fish feeding - photobioreactors - eicosapentaenoic acid - oxygen

    ANannochloropsissp. is a promising microalgal resource for production of food, feed and bio-based commodities, as it can grow relatively fast and combines high lipid content with high content of poly-unsaturated fatty acids. High productivity with constant product quality can be achieved in fully controlled closed photobioreactors. In these closed photobioreactors, however, oxygen accumulation occurs and causes inhibition of the growth by photorespiration combined with photoinhibition.

    The inhibitory effects of photorespiration and photoinhibition can be partly dealt with via the carbon concentration mechanism of the cells and by activation of the water-water cycle. At constant high oxygen concentration and high light intensity, however, the growth of the cells ceases. To our surprise, the accumulating oxygen did not affect the growth rate of the algae if the oxygen was removed regularly. In large scale production in closed photobioreactors, it is thus crucial apply degassing to achieve high algal productivity.

    Oxygen accumulation in photobioreactors
    Fonseca e Sousa, C.A. da - \ 2013
    Wageningen University. Promotor(en): Rene Wijffels, co-promotor(en): Marian Vermue. - S.l. : s.n. - ISBN 9789461735546 - 121
    fotobioreactoren - zuurstof - algen - algenteelt - ontgassing - photobioreactors - oxygen - algae - algae culture - degassing

    Phototropic microalgae are regarded as a promising feedstock for sustainable biodiesel production, as microalgae can use natural sunlight as light source and are able to utilize CO2from flue gases and nutrients (P, N) from waste streams. To make large-scale outdoor microalgae production in closed photobioreactors economically feasible and sustainable, the costs for mixing and degassing should be reduced and the overall energy balance should become positive. This thesis focused on the effect of the accumulation of oxygen on the growth of the oleaginous microalga Neochloris oleoabundansat different light intensities. This study showed at what concentrations oxygen becomes toxic for the algae at the different light conditions encountered during outdoor cultivation and different strategies to overcome the inhibiting factor. The implementations of the main findings of this thesis wereevaluated using an economic model. The model was used to calculatethe energy and costs associated to microalgal biomass production in The Netherlands.The two methods adopted to overcome the negative effect of oxygen in microalgal cultures did result in a decrease in biomass production costs. Moreover, it showed that using the findings of this thesis, a positive energy balance for outdoor production of Neochloris oleoabundans in closed photobioreactors can be reached.

    Uncertainty and sensitivity analysis of algae production models for flat panel photobioreactors
    Stefanov, M.S. ; Slegers, P.M. ; Boxtel, A.J.B. van - \ 2012
    gewasgroeimodellen - algen - algenteelt - oogstvoorspelling - fotobioreactoren - onderzoeksprojecten - biobased economy - biomassa productie - crop growth models - algae - algae culture - yield forecasting - photobioreactors - research projects - biobased economy - biomass production
    Poster met onderzoeksinformatie.
    Cultivation of microalgae in a high irradiance area
    Cuaresma, M. - \ 2011
    Wageningen University. Promotor(en): Rene Wijffels, co-promotor(en): Marcel Janssen. - [S.l.] : S.n. - ISBN 9789085859543 - 197
    algen - algenteelt - bestraling - chlorella sorokiniana - fotobioreactoren - klimaatfactoren - algae - algae culture - irradiation - chlorella sorokiniana - photobioreactors - climatic factors

    Microalgae are a promising source of high-value products (i.e. carotenoids, ω-3 fatty acids), as well as feedstocks for food, bulk chemicals and biofuels. Industrial production is, however, still limited because the technology needs further development. One of the main bottlenecks is the low efficiency of sunlight usage -the main substrate for growth- achieved under outdoor conditions.
    Locations with high irradiances, and moderate temperatures, along the year are considered optimal for microalgae production. However, an excess of sunlight can also be negative and the cells can be damaged. Under these conditions, the resulting photosynthetic efficiency is low, leading to a low biomass productivity. In this sense, maximization of photosynthetic efficiency in areas with much sunlight is required for commercial purposes. In this Thesis, the effects of simulated winter and summer sunlight conditions on the production of microalgae are evaluated. It is proven that photosynthetic efficiency can be highly improved via the light dilution effect. The injurious effects of excessive light are minimized and/or avoided since a lower amount of light is received per cell when photobioreactors are placed vertically. The production of microalgae in locations with much sunlight should be thus considered.

    AlgaePARC : Algae Production and Research Center
    Wijffels, R.H. - \ 2011
    biobased economy - algenteelt - teeltsystemen - fotobioreactoren - proefstations - biobased economy - algae culture - cropping systems - photobioreactors - experimental stations
    Poster met informatie over de opzet van het AlgaePARC in 2011.
    Towards high productivities of microalgae in photobioreactors
    Bosma, R. - \ 2010
    Wageningen University. Promotor(en): Rene Wijffels; Hans Tramper, co-promotor(en): Marian Vermue. - [S.l. : S.n. - ISBN 9789085855590 - 133
    bioreactoren - algen - fotosynthese - licht - lichtregiem - oogsten - screenen - stammen (biologisch) - ultrageluid - onderwijs - lesmaterialen - fotobioreactoren - bioreactors - algae - photosynthesis - light - light regime - harvesting - screening - strains - ultrasound - education - teaching materials - photobioreactors
    The biodiversity of microalgae is enormous and they represent an almost untapped source of unique algae products. Presently, there is a niche market for high-value algal products (e.g. carotenoids and fatty acids). To make commercial production of low-value bulk products possible, still many bottlenecks should be solved. This thesis addresses several of these bottlenecks.
    Based on research on the light conversion by the microalgae, a model was developed that predicts the minimal and maximal productivity of the microalgae in a photobioreactor. In addition, a screening method was developed for fast determination of the growth rate of microalgae. This method can be used to optimize the growth medium as well as to optimize cultivation conditions. We used this method to determine the growth inhibiting effects of free fatty acids on a microalga. In addition, the application of ultrasound as harvesting process for microalgae was investigated. It was found that ultrasound could indeed be used to harvest microalgae, but that this process was commercially only feasible for special applications on small scale. Because algal technology is a relatively new research field, learning materials should be developed for appropriate education in this field. This thesis describes the development of a practical in which third year BSc students learn how to cultivate microalgae and to develop a production strategy to achieve as much ß-carotene production as possible using these algae. Finally, the research described above is evaluated and further research strategies are identified to push microalgal technology ahead and to achieve higher productivity of microalgae in photobioreactors in the future.

    The green solar collector: optimization of microalgal areal productivity
    Zijffers, J.F. - \ 2009
    Wageningen University. Promotor(en): Rene Wijffels; Hans Tramper, co-promotor(en): Marcel Janssen. - [S.l.] : S.n. - ISBN 9789085853015 - 156
    algen - algenteelt - bioreactoren - zonnestraling - chlorella sorokiniana - ontwerp - fotobioreactoren - procesontwerp - algae - algae culture - bioreactors - solar radiation - chlorella sorokiniana - design - photobioreactors - process design
    De Groene Zonnecollector (GZC) is een fotobioreactor die is ontworpen voor efficiënte teelt van microalgen op zonlicht. De zon wordt gevolgd door lenzen die het zonlicht op zogenaamde light guides focussen en waarin het licht reflecteerd en naar de algen geleid wordt. Ray-tracing simulaties laten zien dat bij een hogere zonnestand het zonlicht efficient wordt ingevangen en met een lagere intensiteit aan de algen wordt aangeboden. Deze vermindering van de intensiteit van zonlicht resulteert in hogere opbrengsten, als de bijbehorende biomassa concentratie en lichtweg verder is geoptimaliseerd. Een lage biomassa concentratie zal leiden tot grote reactorvolumes. Hoge biomassa dichtheden hebben dan ook de voorkeur. Echter, wanneer hoge biomassa concentraties worden gecombineerd met een grote lichtweg, dan is de gemiddelde lichtintensiteit in de fotobioreactor te laag. Dit zal leiden tot een geringe specifieke groeisnelheid en door de energiebehoefte voor onderhoud zal dit resulteren in een verlaging van de productiviteit.
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