Bruins, M.E., Meersman, F., Janssen, A.E.M., Heremans, K., Boom, R.M.
The stability of ß-glucosidase from the hyperthermophile Pyrococcus furiosus was studied as a function of pressure, temperature and pH. The conformational stability was monitored using FTIR...
A three-phase microfluidic chip for rapid sample clean-up of alkaloids from plant extracts (2009)
Tetala, K.K.R., Swarts, J.W., Chen, B., Janssen, A.E.M.
A three-phase microchip was developed for the rapid and efficient small-scale purification of alkaloids from plant extracts. As part of the development of such a three-phase microchip, first a...
Pressure-Aided Proteolysis of ß-Casein (2009)
Bruins, M.E., Creusot, N.P., Gruppen, H., Janssen, A.E.M., Boom, R.M.
ß-Casein, which is present in the form of micelles at atmospheric pressure, has been hydrolyzed during pressure treatment to improve the accessibility of the protein. Two proteolytic enzymes with...
Comparison of two-phase lipase-catalyzed esterification on micro and bench scale (2008)
Swarts, J.W., Vossenberg, P., Meerman, M.H., Janssen, A.E.M., Boom, R.M.
Lipase type B from Candida antarctica was used to catalyze the esterification of propionic acid and 1-butanol in a water/n-decane two-phase system on micro and on bench scale. The reaction was...
Baks, T., Kappen, F.H.J., Janssen, A.E.M., Boom, R.M.
The enzymatic hydrolysis of starch is usually carried out with 30¿35 w/w% starch in water. Higher substrate concentrations (50¿70 w/w%) were reached by using a twin-screw extruder for...
Baks, T., Kappen, F.H.J., Janssen, A.E.M., Boom, R.M.
The enzymatic hydrolysis of starch is usually carried out with 30¿35 w/w% starch in water. Higher substrate concentrations (50¿70 w/w%) were reached by using a twin-screw extruder for...
Methylation in methanol-water mixtures: the effect of solvent quality and high-pressure (2008)
Bruins, M.E., Bekers, K.M., Janssen, A.E.M., Boom, R.M.
The effect of pressure (0.1 to 400 MPa) and solvent composition (methanol concentration of 5 to 30%) on the synthesis of ß-methylgalactoside was studied. Galactose was used as a reactant and the...
Baks, T., Bruins, M.E., Matser, A.M., Janssen, A.E.M., Boom, R.M.
Enzymatic hydrolysis of starch can be used to obtain various valuable hydrolyzates with different compositions. The effects of starch pretreatment, enzyme addition point, and hydrolysis conditions on...
Baks, T., Bruins, M.E., Janssen, A.E.M., Boom, R.M.
The effects of pressure, temperature, and treatment time on the degree of gelatinization were determined with differential scanning calorimetry measurements for wheat starch¿water mixtures with...
Besselink, T., Baks, T., Janssen, A.E.M., Boom, R.M.
A stochastic model was developed that was used to describe the formation and breakdown of all saccharides involved during -amylolytic starch hydrolysis in time. This model is based on the subsite...
Temperature effects during practical operation of microfluidic chips (2008)
Swarts, J.W., Janssen, A.E.M., Boom, R.M.
The temperature dependent fluorescence of Rhodamine B was used to investigate the temperature effect of several system parameters in a microfluidic chip. This was combined with computational fluid...
Baks, T., Ngene, I.S., Janssen, A.E.M., Boom, R.M.
A general procedure was developed to measure the degree of gelatinisation in samples over a broad concentration range. Measurements based on birefringence, DSC (Differential scanning calorimetry),...
Bruins, M.E., Matser, A.M., Janssen, A.E.M., Boom, R.M.
Biochemical systems are best studied under buffered conditions and it is, therefore, necessary to have good knowledge on the pressure-induced changes in buffer pH. For experiments conducted at a set...
Modeling of product removal during enzymatic conversions by using affinity molecules (2007)
Halsema, D.G.R., Janssen, A.E.M., Boom, R.M.
The feasibility of using magnetic particles for in-line product isolation during enzymatic conversion was studied. A comparison was made between a process based on magnetic particles and a...
Baks, T., Bruins, M.E., Janssen, A.E.M., Boom, R.M.
The effects of pressure, temperature, and treatment time on the degree of gelatinization were determined with differential scanning calorimetry measurements for wheat starch¿water mixtures with...
Baks, T., Bruins, M.E., Matser, A.M., Janssen, A.E.M., Boom, R.M.
Enzymatic hydrolysis of starch can be used to obtain various valuable hydrolyzates with different compositions. The effects of starch pretreatment, enzyme addition point, and hydrolysis conditions on...
Chip-holder for a micro-fluidic chip (2007)
Trieu, H.K., Bollerott, M., Kemmerling, M., Hildebrand, R., Rutjes, F., ...
The effect of carbohydrates on alpha-amylase activity measurements (2006)
Baks, T., Janssen, A.E.M., Boom, R.M.
The Ceralpha method can be used for ¿-amylase activity measurements during the hydrolysis of starch at high substrate concentrations (>40 wt.%). However, the results are affected by the...
Equilibrium shifts in enzyme reactions at high pressure (2006)
Bruins, M.E., Janssen, A.E.M., Boom, R.M.
The effect of pressure on the equilibrium of a reaction was studied. Theoretical equilibrium constants and product concentrations have been calculated at elevated pressures. The theory is illustrated...
Baks, T., Janssen, A.E.M., Boom, R.M.
The effect of the presence of several small carbohydrates on the measurement of the -amylase activity was determined over a broad concentration range. At low carbohydrate concentrations, a distinct...
Solvent selection for solid-to-solid synthesis (2002)
Ulijn, R. V., De Martin, L., Gardossi, L., Janssen, A. E. M., Moore, B. D., Halling, P. J.
Thermolysin catalyzed solid-to-solid synthesis of the model peptide Z-L-Phe-L-Leu-NH2 is practically feasible in water and a range of organic solvents with different physicochemical properties....
Solvent selection for solid-to-solid synthesis (2002)
Ulijn, R.V., De Martin, L., Gardossi, L., Janssen, A.E.M., Moore, B.D., Halling, P.J.
Thermolysin catalyzed solid-to-solid synthesis of the model peptide Z-L-Phe-L-Leu-NH2 is practically feasible in water and a range of organic solvents with different physicochemical properties....
Solvent selection for solid-to-solid synthesis (2002)
Ulijn, R.V., De Martin, L., Gardossi, L., Janssen, A.E.M., Moore, B.D., Halling, P.J.
Thermolysin catalyzed solid-to-solid synthesis of the model peptide Z-L-Phe-L-Leu-NH2 is practically feasible in water and a range of organic solvents with different physicochemical properties....
Enzymatic synthesis of beta-lactam antibiotics via direct condensation (2002)
Ulijn, R. V., De Martin, L., Halling, P. J., Moore, B. D., Janssen, A. E. M.
In this paper, the feasibility of precipitation driven synthesis of acidic and zwitterionic beta-lactam antibiotics is studied. As an example of the first type, penicillin G was produced in good...
Enzymatic synthesis of beta-lactam antibiotics via direct condensation (2002)
Ulijn, R.V., De Martin, L., Halling, P.J., Moore, B.D., Janssen, A.E.M.
In this paper, the feasibility of precipitation driven synthesis of acidic and zwitterionic beta-lactam antibiotics is studied. As an example of the first type, penicillin G was produced in good...
Enzymatic synthesis of beta-lactam antibiotics via direct condensation (2002)
Ulijn, R.V., De Martin, L., Halling, P.J., Moore, B.D., Janssen, A.E.M.
In this paper, the feasibility of precipitation driven synthesis of acidic and zwitterionic beta-lactam antibiotics is studied. As an example of the first type, penicillin G was produced in good...
Reversible acetonitrile-induced inactivation/activation of thermolysin (2002)
Ulijn, R. V., Janssen, A. E. M., Moore, B. D., Halling, P. J., Kelly, S. M., Price, N. C.
Thermolysin is catalytically inactive in mixtures or 70-15% acetonitrile in aqueous buffer. Unexpectedly, dilution of the inactive enzyme with acetonitrile leads to complete recovery of the catalytic...
Reversible acetonitrile-induced inactivation/activation of thermolysin (2002)
Ulijn, R.V., Janssen, A.E.M., Moore, B.D., Halling, P.J., Kelly, S.M., Price, N.C.
Thermolysin is catalytically inactive in mixtures or 70-15% acetonitrile in aqueous buffer. Unexpectedly, dilution of the inactive enzyme with acetonitrile leads to complete recovery of the catalytic...
Reversible acetonitrile-induced inactivation/activation of thermolysin (2002)
Ulijn, R.V., Janssen, A.E.M., Moore, B.D., Halling, P.J., Kelly, S.M., Price, N.C.
Thermolysin is catalytically inactive in mixtures or 70-15% acetonitrile in aqueous buffer. Unexpectedly, dilution of the inactive enzyme with acetonitrile leads to complete recovery of the catalytic...
A single aqueous reference equilibrium constant for amide synthesis-hydrolysis (2002)
Ulijn, R.V., Moore, B.D., Janssen, A.E.M., Halling, P.J.
Experimentally measured equilibrium constants at a given pH in part reflect the contributions of ionisation of acidic and basic groups present. These contributions can be isolated from the...
Integrated reactor concepts for the enzymatic kinetic synthesis of cephalexin (2002)
Nierstrasz, V.A., Bosma, R., Kroon, P.J., Tjeerdsma, P.S., DeVroom, E., ...
Integrated process concepts for enzymatic cephalexin synthesis were investigated by our group, and this article focuses on the integration of reactions and product removal during the reactions. The...
Modelling of the enzymatic kinetically controlled synthesis of cephalexin (2002)
Fretz, C.B., Berendsen, W., Moody, H.M., Roos, E.C., ...
In this study the influence of diffusion limitation on enzymatic kinetically controlled cephalexin synthesis from phenylglycine amide and 7-aminodeacetoxycephalosporinic acid (7-ADCA) was...
Enhancement of enzymatic adipyl-7-ADCA hydrolysis (2002)
Kroon, P.J., Vanderlaan, J.M., Janssen, A.E.M., Tramper, J.
We studied enzymatic adipyl-7-ADCA hydrolysis as a new process for the production of 7-aminodeacetoxycephalosporanic acid (7-ADCA), one of the building blocks for cephalosporin antibiotics like...
Enzymatic synthesis of ß-lactam antibiotics via direct condensation (2002)
Ulijn, R.V., Halling, P.J., Moore, B.D., Janssen, A.E.M.
In this paper, the feasibility of precipitation driven synthesis of acidic and zwitterionic -lactam antibiotics is studied. As an example of the first type, penicillin G was produced in good yield...
Solvent selection for solid-to-solid synthesis (2002)
Ulijn, R.V., Gardossi, L., Janssen, A.E.M., Moore, B.D., Halling, P.J.
Thermolysin catalyzed solid-to-solid synthesis of the model peptide Z-L-Phe-L-Leu-NH2 is practically feasible in water and a range of organic solvents with different physicochemical properties....
Reversible acetonitrile-induced inactivation/activation of thermolysin (2002)
Ulijn, R.V., Janssen, A.E.M., Moore, B.D., Halling, P.J., Kelly, S.M., Price, N.C.
A single aqueous reference equilibrium constant for amide synthesis-hydrolysis (2002)
Ulijn, R. V., Moore, B. D., Janssen, A. E. M., Halling, P. J.
Experimentally measured equilibrium constants at a given pH in part reflect the contributions of ionisation of acidic and basic groups present. These contributions can be isolated from the...
Integrated reactor concepts for the enzymatic kinetic synthesis of cephalexin (2002)
Nierstrasz, V.A., Bosma, R., Kroon, P.J., Tjeerdsma, P.S., Vroom, E. De, ...
A single aqueous reference equilibrium constant for amide synthesis-hydrolysis (2002)
Ulijn, R.V., Moore, B.D., Janssen, A.E.M., Halling, P.J.
Experimentally measured equilibrium constants at a given pH in part reflect the contributions of ionisation of acidic and basic groups present. These contributions can be isolated from the...
A single aqueous reference equilibrium constant for amide synthesis-hydrolysis (2002)
Ulijn, R.V., Moore, B.D., Janssen, A.E.M., Halling, P.J.
Experimentally measured equilibrium constants at a given pH in part reflect the contributions of ionisation of acidic and basic groups present. These contributions can be isolated from the...
Predicting when precipitation-driven synthesis is feasible: Application to biocatalysis (2001)
Ulijn, R. V., Janssen, A. E. M., Moore, B. D., Halling, P. J.
Precipitation-driven synthesis offers the possibility of obtaining high reaction yields using very low volume reactors and is finding increasing applications in biocatalysis. Here, a model that...
Predicting when precipitation-driven synthesis is feasible: Application to biocatalysis (2001)
Ulijn, R.V., Janssen, A.E.M., Moore, B.D., Halling, P.J.
Precipitation-driven synthesis offers the possibility of obtaining high reaction yields using very low volume reactors and is finding increasing applications in biocatalysis. Here, a model that...
Predicting when precipitation-driven synthesis is feasible: Application to biocatalysis (2001)
Ulijn, R.V., Janssen, A.E.M., Moore, B.D., Halling, P.J.
Precipitation-driven synthesis offers the possibility of obtaining high reaction yields using very low volume reactors and is finding increasing applications in biocatalysis. Here, a model that...
Predicting when precipitation-driven synthesis is feasible : application to biocatalysis (2001)
Ulijn, R.V., Janssen, A.E.M., Moore, B.D., Halling, P.J.
Precipitation-driven synthesis offers the possibility of obtaining high reaction yields using very low volume reactors and is finding increasing applications in biocatalysis. Here, a model that...
Thermozymes and their applications (2001)
Bruins, M.E., Janssen, A.E.M., Boom, R.M.
Enzymes from thermophilic microorganisms, thermozymes, have unique characteristics such as temperature, chemical, and pH stability. They can be used in several industrial processes, in which they...
Mohy Eldin, M.S., Janssen, A.E.M., Tramper, J.
The effect of thermodialysis on the enzymatic kinetic synthesis of the antibiotic cephalexin was investigated. As reference points, two existing models for an immobilised enzyme (Assemblase?) and for...
Biocatalytic production of semi-synthetic cephalosporis: process technology and integration (2001)
Tramper, J., Beeftink, H.H., Janssen, A.E.M., Ooijkaas, L.P., Strubel, M., ...
In this article, the enzymatic production of oligosaccharides, which is an example of a kinetically controlled reaction, is studied. The aim is to show that the product yield can be enhanced by...
Flores, M.V., Sewalt, J.J.W., Janssen, A.E.M.
The equilibrium position in lipase mediated esterification of various fatty acids and butanol was studied. The influence of the chain length and the presence of unsaturations in the fatty acids on...
Mohy Eldin, M.S., Santucci, M., Rossi, S., Tramper, J., Janssen, A.E.M., ...
A new catalytic membrane has been prepared using a nylon membrane grafted by -radiation with methylmethacrylate (MMA) and using hexamethylenediamine (HMDA) as spacer. Penicillin G acylase (PGA) and...
Equilibrium position, kinetics, and reactor concepts for the adipyl-7-ADCA-hydrolysis process (2000)
Kroon, P.J., Janssen, A.E.M., Tramper, J.
One of the building blocks of cephalosporin antibiotics is 7-amino-deacetoxycephalosporanic acid (7-ADCA). It is currently produced from penicillin G using an elaborate chemical ring-expansion step...
Thermodynamically controlled synthesis of cefamandole (1999)
Nierstrasz, V.A., Bosma, R., Kroon, P.J., Beeftink, H.H., Janssen, A.E.M., ...
Thermodynamically controlled synthesis of cefamandole (1999)
Nierstrasz, V.A., Bosma, R., Kroon, P.J., Beeftink, H.H., Janssen, A.E.M., ...
Enzymatic synthesis of polyol esters in aqueous-organic two-phase systems. (1993)
http://library.wur.nl/wda/abstracts/ab1640.html
Multicomponent diffusion in dialysis membranes. (1992)
Keurentjes, J.T.F., Janssen, A.E.M., Broek, A.P., Wesselingh, J.A.
The effect of organic solvents on enzymatic esterification of polyols. (1992)
Janssen, A.E.M., Hadini, M., Wessels Boer, N., Walinga, R., ...