Cuaresma, M., Janssen, M.G.J., Vilchez, C., Wijffels, R.H.
Maximal productivity of a 14 mm light-path panel photobioreactor under high irradiance was determined. Under continuous illumination of 2,100 µmol photons m-2 s-1 with red light emitting diodes...
Cell cultures from the symbiotic soft coral Sinularia flexibilis (2008)
Mohammad K. Khalesi, D. K. Aanen, H. H. Beeftink, R. H. Wijffels
The growth dynamics and survival of the sponge Corticium candelabrum (Demospongiae: Homosclerophorida) were surveyed in the northwestern Mediterranean for more than 3 yr. Growth and regeneration...
Design process of an area-efficient photobioreactor (2008)
Zijffers, J.F., Janssen, M.G.J., Tramper, J., Wijffels, R.H.
This article describes the design process of the Green Solar Collector (GSC), an area-efficient photobioreactor for the outdoor cultivation of microalgae. The overall goal has been to design a system...
Environmental Flow Regimes for Dysidea avara Sponges (2008)
Mendola, D., Uriz, M.J., Wijffels, R.H.
The aim of our research is to design tank systems to culture Dysidea avara for the production of avarol. Flow information was needed to design culture tanks suitable for effective production. Water...
Environmental Flow Regimes for Dysidea avara Sponges (2008)
Mendola, D., Uriz, M.J., Wijffels, R.H.
The aim of our research is to design tank systems to culture Dysidea avara for the production of avarol. Flow information was needed to design culture tanks suitable for effective production. Water...
Seasonal Growth Rate of the Sponge Haliclona oculata (Demospongiae: Haplosclerida) (2008)
The interest in sponges has increased rapidly since the discovery of potential new pharmaceutical compounds produced by many sponges. A good method to produce these compounds by using aquaculture of...
Lamers, P.P., Janssen, M.G.J., Bino, R.J., Wijffels, R.H.
The unicellular alga Dunaliella salina is the most interesting cell factory for the commercial production of ß-carotene because this species accumulates carotenoids to high concentrations....
Lamers, P.P., Janssen, M., Bino, R.J., Wijffels, R.H.
The unicellular alga Dunaliella salina is the most interesting cell factory for the commercial production of [beta]-carotene because this species accumulates carotenoids to high concentrations....
Growth inhibition of Monodus subterraneus by free fatty acids (2008)
Bosma, R., Miazek, K., Willemsen, S.M., Vermuë, M.H., Wijffels, R.H.
Monodus subterraneus is a microalga, which is known for its high eicosapentaenoic acid (EPA; 20:5omega3) content. To produce EPA commercially, high volumetric productivities of microalgae are...
Schutter, M., Janse, M., Osinga, R., Janssen, M., Wijffels, R.H., ...
The relation between irradiance, skeletal growth and net photosynthesis was studied for the scleractinian coral Galaxea fascicularis to provide experimental evidence for mediation of light-enhanced...
Cell cultures from the symbiotic soft coral Sinularia flexibilis (2008)
Khalesi, M.K., Vera-Jimenez, N.I., Aanen, D.K., Beeftink, H.H., Wijffels, R.H.
The symbiotic octocoral Sinularia flexibilis is a producer of potential pharmaceuticals. Sustainable mass production of these corals as a source of such compounds demands innovative approaches,...
Khalesi, M.K., Beeftink, H.H., Wijffels, R.H.
The branching zooxanthellate soft coral Sinularia flexibillis releases antimicrobial and toxic compounds with potential pharmaceutical importance. As photosynthesis by the symbiotic algae is vital to...
Zijffers, J.F., Janssen, M.G.J., Tramper, J., Wijffels, R.H., Salim, S.
The Green Solar Collector (GSC), a photobioreactor designed for area efficient outdoor cultivation of microalgae uses Fresnel lenses and light guides to focus, transport and distribute direct light...
Biocalorimetric monitoring of photoautotrophic batch cultures (2007)
Janssen, M.G.J., Wijffels, R.H.
Cultivations of photoautotrophic microorganisms show a rather distinct behavior from the cultivations of microorganisms on chemical energy. This is caused by the fact that light energy is the...
Prediction of volumetric productivity of an outdoor photobioreactor (2007)
Bosma, R., Reith, J.H., Tramper, J., Wijffels, R.H.
Volumetric productivity of Monodus subterraneus cultivated in an outdoor pilot-plant bubble column was predicted with a mathematical model. Two border cases to model the photobioreactor were chosen....
Flow-dependent growth in the zooxanthellate soft coral Sinularia flexibilis (2007)
Khalesi, M.K., Beeftink, H.H., Wijffels, R.H.
Growth characteristics of colonies of the branching zooxanthellate octocoral Sinularia flexibilis, with potential pharmaceutical importance, were measured over a range of water velocities. The...
Cell culture from sponges: pluripotency and immortality (2007)
Sponges are a source of compounds with potential pharmaceutical applications. In this article, methods of sponge cell culture for production of these bioactive compounds are reviewed, and new...
Oxygen dynamics and flow patterns of Dysidea avara (Porifera: Demospongiae) (2007)
Schläppy, M.L., Hoffmann, F., Roy, H., Wijffels, R.H., Mendola, D., Sidri, M., ...
Cultivation of sponge larvae: settlement, survival, and growth of juveniles (2007)
Otjens, H., Uriz, M.J., Wijffels, R.H.
The aim of this study was to culture sponge juveniles from larvae. Starting from larvae we expected to enhance the survival and growth, and to decrease the variation in these parameters during the...
Embryo development of Corticium candelabrum (Demospongiae: Homosclerophorida) (2007)
Uriz, M.J., Ereskovsky, A.V., Wijffels, R.H.
Corticium candelabrum is a homosclerophorid sponge widespread along the rocky Mediterranean sublittoral. Scanning and transmission electron microscopy were used to describe the gametes and larval...
Potential of sponges and microalgae for marine biotechnology (2007)
Marine organisms can be used to produce several novel products that have applications in new medical technologies, in food and feed ingredients and as biofuels. In this paper two examples are...
Hypothesized kinetic models for describing the growth of globular and encrusting demosponges (2006)
Sipkema, D., Yosef, N.A.M., Adamczewski, M., Osinga, R., Mendola, D., Tramper, J., ...
The marine sponges Dysidea avara and Chondrosia reniformis (globular forms) were cultured in the laboratory on a diet of viable Phaeodactylum tricornutum cells and dissolved nutrients (algae and fish...
Hoekema, S., Douma, R.D., Janssen, M.G.J., Tramper, J., Wijffels, R.H.
The main bottleneck in scale-up of phototrophic fermentation is the low efficiency of light energy conversion to the desired product, which is caused by an excessive dissipation of light energy to...
Biomass for biological hydrogen production (2006)
Claassen, P.A.M., Budde, M.A.W., Stams, A.J.M., Goorissen, H.P., Wijffels, R.H., Hoekema, S., ...
Large-scale production of pharmaceuticals by marine sponges: Sea, cell, or synthesis? (2005)
Sipkema, D., Osinga, R., Schatton, W., Mendola, D., Tramper, J., Wijffels, R.H.
Marine sponges are known to produce an overwhelming array of secondary metabolites with pharmaceutical potential. The technical and economical potential of using marine sponges for large-scale...
Marine sponges as pharmacy (2005)
Sipkema, D., Franssen, M.C.R., Osinga, R., Tramper, J., Wijffels, R.H.
Marine sponges have been considered as a gold mine during the past 50 years, with respect to the diversity of their secondary metabolites. The biological effects of new metabolites from sponges have...
The life and death of sponge cells (2004)
Sipkema, D., Snijders, A.P.L., Osinga, R., Wijffels, R.H.
Cell viability is an essential touchstone in the study of the effect of medium components on cell physiology. We developed a flow-cytometric assay to determine sponge-cell viability, based on the...
Milking microalga Dunaliella salina for Beta-carotene production in two-phase bioreactors (2004)
Hejazi, M., Holwerda, E., Wijffels, R.H.
new method was developed for production of -carotene from Dunaliella salina. Cells were grown in low light intensity and then transferred to a production bioreactor illuminated at a higher light...
Overcoming shear stress of microalgae cultures in sparged photobioreactors (2004)
Barbosa, M.J., Hadiyanto, H., Wijffels, R.H.
In the present work we identified and quantified the effect of hydrodynamic stress on two different microalgae strains, Dunaliella tertiolecta and D. salina, cultivated in bench-scale bubble columns....
The low productivity of algal cultures in the production of high-value compounds is the most significant bottleneck for commercialization of this technology. Cultures in which cell mass is reused for...
Janssen, M.G.J., Tramper, J., Mur, L.R., Wijffels, R.H.
Enclosed outdoor photobioreactors need to be developed and designed for large-scale production of phototrophic microorganisms. Both light regime and photosynthetic efficiency were analyzed in...
Primmorphs from seven marine sponges : formation and structure (2003)
Sipkema, D., Tramper, J., Osinga, R., Wijffels, R.H.
Primmorphs were obtained from seven different marine sponges: Stylissa massa, Suberites domuncula, Pseudosuberites aff. andrewsi, Geodia cydonium, Axinella polypoides, Halichondria panicea and...
Barbosa, M.J., Janssen, M.G.J., Ham, N., Tramper, J., Wijffels, R.H.
The slow development of microalgal biotechnology stems from the failure in the design of large-scale photobioreactors where light energy is efficiently utilized. Due to the light gradient inside the...
Sponge cell culture? A molecular identification method for sponge cells (2003)
Sipkema, D., Heilig, G.H.J., Akkermans, A.D.L., Osinga, R., Tramper, J., Wijffels, R.H.
Dissociated sponge cells are easily confused with unicellular organisms. This has been an obstacle in the development of sponge-cell lines. We developed a molecular detection method to identify cells...
Realizing the promises of marine biotechnology (2003)
Luiten, E.E.M., Akkerman, I., Koulman, A., Kamermans, P., Reith, H., Barbosa, M.J., ...
High-quality research in the field of marine biotechnology is one of the key-factors for successful innovation in exploiting the vast diversity of marine life. However, fascinating scientific...
Photobiological hydrogen production: Photochemical efficiency and bioreactor design (2003)
Akkerman, I., Janssen, M.G.J., Rocha, J.M.S., Reith, J.H., Wijffels, R.H.
What to do in marine biotechnology? (2003)
Tramper, J., Battershill, C., Brandenburg, W.A., Burgess, G., Hill, R., Luiten, E.E.M., ...
During the symposium "Marine Biotechnology: Basics and Applications", held 25 February¿1 March, 2003 in Matalascañas, Spain, a special brainstorm session was organized. Two questions were...
High-cell density cultures: Design and operational characteristics of photobioreactors (2003)
Barbosa, M.J., Janssen, M.G.J., Richmond, A., Wijffels, R.H.
Reith, J.H., Albracht, S.P.J., Bleijlevens, B., Hagen, W.R., Stams, A.J.M., Keltjens, J.T., ...
Deze rapportage beschrijft de uitkomsten van een inventarisatie onder onderzoekers verbonden aan Nederlandse kennisinstellingen. Het doel van de inventarisatie is: 1. Het in kaart brengen van lopend...
Marine biotechnology: basics and applications (2003)
Wijffels, R.H., Barbosa, M., Janssen, M., Wessels, H.S., Tramper, J., Vilchez, C., ...
T.R. - Biomolecular Engineering (2003)
Wijffels, R.H., Barbosa, M.J., Janssen, M.G.J., Tramper, J., Vilchez Lobato, C., ...
Hejazi, M.A., Rocha, J.M.S., Vermuë, M., Tramper, J., Wijffels, R.H.
Simultaneous production and selective extraction of -carotene from living cells of Dunaliella salina in a two-phase system of aqueous and organic phases has been investigated. Solvents with values of...
Photobiological hydrogen production : photochemical efficiency and bioreactor design (2002)
Akkerman, I., Janssen, M., Rocha, J., Wijffels, R.H.
Biological production of hydrogen can be carried out by photoautotrophic or photoheterotrophic organisms. Here, the photosystems of both processes are described. The main drawback of the...
Rahardjo, Y.S.P., Smit, B.A., Kroon, P.J., Hartmans, S., ...
Alpha-keto acids are key intermediates in the formation of higher alcohols, important flavor components in soy sauce, and produced by the salt-tolerant yeast Zygosaccharomyces rouxii. Unlike most of...
Photosynthetic efficiency of Dunaliella tertiolecta under short light/dark cycles (2001)
Janssen, M., Slenders, P., Tramper, J., Mur, L.R., Wijffels, R.H.
Estimation of steady-state culture characteristics during acceleration-stats with yeasts (2001)
Westerink, B.H., Dijkstal, M.M., Castelein, S.J., Tramper, J., ...
Steady-state culture characteristics are usually determined in chemostat cultivations, which are very time-consuming. In contrast, acceleration-stat (A-stat) cultivations in which the dilution rate...
Solid-to-solid bioconversions: batch or continuous? (2001)
Michielsen, M.J.F., Wijffels, R.H., Tramper, J., Beeftink, H.H.
Osinga, R., Kleijn, R., Groenendijk, E., Niesink, P., Tramper, J., Wijffels, R.H.
The rate of food particle uptake of the tropical sponge Pseudosuberites aff. andrewsi was studied in relation to particle concentrations and particle size. A range of different concentrations of...
In soy-sauce processes salt-tolerant yeasts are very important for the flavour formation. This flavour formation is, however, slow and poorly understood. In the last decades, a concerted research...
Photosynthetic efficiency of Dunaliella tertiolecta under short light/dark cycles (2001)
Janssen, M., Slenders, P., Tramper, J., Mur, L.R., Wijffels, R.H.
Janssen, M., Tramper, J., Mur, L.R., Snel, J., Wijffels, R.H.
The light regime inside a photobioreactor is characterized by a light gradient with full (sun)light at the light-exposed surface and darkness in the interior of the bioreactor. Consequently,...
Scale-up aspects of photobioreactors : effects of mixing-induced light/dark cycles (2000)
Janssen, M., Baijens, T., Tramper, J., Mur, L.R., Snel, J.F.H., ...
The green micro-algae Chlamydomonas reinhardtii and Dunaliella tertiolecta were cultivated under medium-duration square-wave light/dark cycles with a cycle time of 15 s. These cycles were used to...
Growth of Ca-D-malate crystals in a bioreactor (2000)
Michielsen, M.J.F., Frielink, C., Wijffels, R.H., Tramper, J., Beeftink, H.H.
To develop a bioreactor for solid-to-solid conversions, the conversion of solid Ca-maleate to solid Ca-D-malate by permeabilized Pseudomonas pseudoalcaligenes was studied. In a bioreactor seeded with...
Modeling solid-to-solid biocatalysis : Integration of six consecutive steps (2000)
Michielsen, M.J.F., Frielink, C., Wijffels, R.H., Tramper, J., Beeftink, H.H.
A quantitative model for the conversion of a solid-substrate salt to a solid-product salt in a batch bioreactor seeded with product crystals is presented. The overall process consists of six serial...
Mulder, A.N.T., Grolle, K.C.F., Engbers, G.H.M., Tramper, J., ...
Entrapment of cells in alginate gel is a widely used mild immobilization procedure. However, alginate gel is not very suitable for use in long-term continuous soy-sauce processes because alginate is...
Smit, B.A., Hartmans, S., Tramper, J., Wijffels, R.H.
To elucidate the growth inhibitory effect of threonine, the regulation of the aspartate-derived amino-acid metabolism in Zygosaccharomyces rouxii, an important yeast for the flavor development in soy...
Vogelsang, C., Wijffels, R.H., Ostgaard, K.
The mechanical stability of gels applied for entrapment and retention of biocatalysts in bioreactors is of crucial importance for successful scale-up applications. Gel abrasion in agitated reactors...
Janssen, M., Janssen, M., Tramper, J., Mur, L.R., Snel, J., ...
Feasibility of biological hydrogen production from biomass for utilization in fuel cells (2000)
Claassen, P.A.M., Groenestijn Van, J.W., Janssen, A.J.H., Wijffels, R.H.
Scale-up aspects of photobioreactors: effects of mixing-induced light/dark cycles. (2000)
Janssen, M., Bresser, L. De, Baijens, T., Tramper, J., Mur, L.R., Snel, J.F.H., ...
Stabilization of maleate-hydratase activity of permeabilized Pseudomonas pseudoalcaligenes (1999)
Michielsen, M.J.F., Frielink, C., Meijer, E.A., Wijffels, R.H., Tramper, J., ...
Cultivation of marine sponges (1999)
Osinga, R., Tramper, J., Wijffels, R.H.
There is increasing interest in biotechnological production of marine sponge biomass owing to the discovery of many commercially important secondary metabolites in this group of animals. In this...
Kinetics of D-malate production by permeabilized Pseudomonas pseudoalcaligenes. (1998)
Michielsen, M.J.F., Meijer, E.A., Wijffels, R.H., Tramper, J., Beeftink, H.H.
Dissolution kinetics of Ca-maleate crystals: evalution for biotransformation reactor design. (1998)
Michielsen, M.J.F., Reijenga, K.A., Wijffels, R.H., Tramper, H., Beeftink, H.H.
Cultivation of marine sponges for metabolite production: applications for biotechnology? (1998)
Osinga, R., Tramper, J., Wijffels, R.H.
The world's oceans harbour a large diversity of living organisms. As tropical rainforests have been searched for natural drugs, these marine organisms are being screened for useful products, and a...
In vitro cultivation of four marine sponge species: determination of the nutritional demands. (1998)
Guidelines for the characterization of immobilized cells. (1996)
Wijffels, R.H., Buitelaar, R.M., Bucke, C., Poulsen, P.B., Lilly, M.D., Cheetmam, P.S.J., ...
Effects of diffusion limitation on immobilized nitrifying microorganisms at low temperatures. (1995)
Wijffels, R.H., Englund, G., Hunik, J.H., Bakketun, A., Gunther, A., ...
Nitrification by immobilized cells. (1994)
http://library.wur.nl/wda/abstracts/ab1800.html
Re-plumbing in a Mediterranean sponge
Mendola, D, Van Leeuwen, J.L, Wijffels, R.H
Observations are reported for Dysidea avara sponges where once functioning oscula (outlets) are converted through internal re-plumbing into functioning oversized ostia (OSO; inlets). Flow tank...