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PEOPLE@HES-SO – Annuaire et Répertoire des compétences
PEOPLE@HES-SO – Annuaire et Répertoire des compétences

PEOPLE@HES-SO
Annuaire et Répertoire des compétences

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Dabros Michal

Dabros Michal

Professeur HES associé

Compétences principales

Chemical and bioprocess engineering

Process monitoring and control

Process Analytical Technology (PAT)

  • Contact

  • Enseignement

  • Recherche

  • Publications

  • Conférences

Contrat principal

Professeur HES associé

Téléphone: +41 26 429 68 79

Bureau: HEIA_H10.17

Haute école d'ingénierie et d'architecture de Fribourg
Boulevard de Pérolles 80, 1700 Fribourg, CH
HEIA-FR
Institut
ChemTech - Institut des technologies chimiques
MSc HES-SO en Life Sciences - HES-SO Master
  • Process design and optimization
BA HES-SO en Architecture - Haute école d'ingénierie et d'architecture de Fribourg
  • Génie chimique
  • Régulation automatique
  • Chemical Process Simulation
  • TP de Chimie industrielle

Terminés

Biocimentation de déblais gréseux
AGP

Rôle: Co-requérant(s)

Requérant(e)s: FR - EIA - Institut iTEC, Labiouse Vincent, FR - EIA - Institut iTEC

Financement: FR - EIA - Général école Ra&D; SLL-2021; SLL-2022

Description du projet : Ce petit projet SLL mené au sein des instituts iTEC et ChemTech vise à se familiariser avec le procédé de bio-cimentation en vue d'une valorisation potentielle de déblais molassiques pour la production d'éléments structurels - ou non - dans le domaine de la construction. Lorsque la proportion de grès prédomine dans la molasse, la technique de bio-cimentation pourrait être envisagée pour valoriser des déblais d'excavation. En effet, elle permet, en mélangeant des bactéries (Sporosarcina pasteurii) avec de l'urée et du chlorure de calcium, d'induire une précipitation de calcite. Les grains de sable constitutifs du grès sont ainsi liés entre eux par ce ciment calcaire, permettant d'obtenir un matériau de construction à faible impact écologique (peu d'énergie grise et d'émissions de CO2).

Equipe de recherche au sein de la HES-SO: Dabros Michal , Breguet Mercier Véronique , Kohler David , Labiouse Vincent , Pollien Jessy , Frei Benjamin

Partenaires académiques: FR - EIA - Institut ChemTech; FR - EIA - Institut iTEC; Labiouse Vincent, FR - EIA - Institut iTEC

Durée du projet: 01.10.2021 - 31.12.2022

Montant global du projet: 64'800 CHF

Statut: Terminé

Développement d'un système automatisé de culture hors-sol accessible aux populations exposées aux déficits alimentaires structurels en Haïti

Rôle: Requérant(e) principal(e)

Financement: HES-SO

Description du projet :

L'insécurité alimentaire en Haïti, liée au manque de denrées agricoles et au faible pouvoir d'achat de la population, s'est accru considérablement durant la dernière décennie en raison des multiples désastres naturels qui ont frappé le pays. Ce projet vise à proposer une technologie durable de culture hors-sol en circuit fermé, avec un recyclage automatisé de la solution nutritive. La technique, adaptée aux conditions locales, permettra aux jeunes entrepreneurs d'assurer une production maraîchère fiable.

Equipe de recherche au sein de la HES-SO: Dabros Michal , Vorlet Olivier

Durée du projet: 01.04.2019 - 31.05.2022

Statut: Terminé

Remote Labs : Plateforme digitale de laboratoires en ligne pour des travaux pratiques à distance

Rôle: Co-requérant(s)

Financement: HES-SO

Description du projet :

Ce projet inter-filière propose une infrastructure digitale composée de plusieurs laboratoires à distance offrant un environnement pédagogique complémentaire aux formations classiques.

Le but est le partage à distance des infrastructures et des ressources pédagogiques par la mise en ligne des laboratoires répartis sur les écoles de la HES-SO.

Les MOOC / MOOLs dévéloppés lors de ce projets :

https://moocs.hes-so.ch/#courseid=106

https://moocs.hes-so.ch/#courseid=134

https://moocs.hes-so.ch/#courseid=135

https://moocs.hes-so.ch/#courseid=136

 

  • Financement : Programme Innovation Pédagogique de la HES-SO
  • Partenaires : HES⁠-⁠SO Valais-Wallis, HEIA-FR

Equipe de recherche au sein de la HES-SO: Moghaddam Fariba , Dabros Michal , Crelier Simon , Vaccari Aldo , Moniquet Thomas , Vorlet Olivier , Forestal Maël

Durée du projet: 01.07.2020 - 30.06.2021

Url du site du projet: https://moocs.hes-so.ch/

Statut: Terminé

Call 2011 Production d'énergie propre en milieu urbain basé sur la transformation du CO2 en méthanol offrant un biocarburant neutre en CO2 utilisé dans le cadre de la mobilité urbaine et d'une autonomisation énergétique des bâtiments.
AGP

Rôle: Collaborateur/trice

Requérant(e)s: FR - EIA - Institut ChemTech

Financement: HES-SO Rectorat

Description du projet : La transformation du CO2 en méthanol représente une énergie propre renouvelable et facile à stocker, permettant à la Suisse de relever les défis environnementaux et économiques en lien avec la problématique de l'énergie. La solution proposée offre une production de carburant neutre en CO2 pour des applications en milieu urbain (voitures et pompes à chaleur utilisant une pile au méthanol) se basant sur une vision de bâtiments et de familles autonomes du point de vue énergique.

Equipe de recherche au sein de la HES-SO: Dabros Michal , Grèzes Vincent , Favre-Perrod Patrick , Sanglard Pauline , Perruchoud Antoine , Bourrier Hervé , Vorlet Olivier , Naef Olivier , Richard Jacques , Chappuis Thierry , Marti Roger , Amrein Daniel , Mamula Steiner Olimpia , Bourgeois Jean-Pascal , Ropp Julien

Partenaires académiques: IGT; VS - Institut Entrepreneuriat & MANAGEMENT; hepia inSTI; FR - EIA - Institut ChemTech; FR - EIA - Institut ENERGY

Durée du projet: 01.03.2012 - 31.12.2014

Montant global du projet: 780'000 CHF

Statut: Terminé

Suivi, contrôle et optimisation en ligne de masse molaire moyenne du PLA produit par extrusion réactive
AGP

Rôle: Requérant(e) principal(e)

Financement: HES-SO Rectorat

Description du projet : L'EIA-FR a précédemment développé un procédé novateur pour la synthèse du PLA. L'acide polylactique (PLA) est un polymère biodégradable, bisourcé et biocompatible. Ses propriétés mécaniques dépendent principalement de sa masse molaire. Du PLA de bas poids moléculaire (10-30 kDa) est amorphe et idéal pour des applications dans le domaine du biomédical (drug release) tandis qu'un PLA de haut poids moléculaire (100-150 kDa) est semi-cristallin et utilisable dans le domaine du packaging. Le PLA est produit en plusieurs étapes à partir de l'acide lactique. La dernière étape, la polymérisation du dilactide (dimère cyclique de l'acide lactique), se fait traditionnellement en mode batch, ce qui présente de nombreux inconvénients (transfert de chaleur, agitation, temps de réaction) mais peut aussi se faire par extrusion réactive, ce qui permet un meilleur contrôle de la réaction et une diminution de temps significative. La masse molaire du PLA est fortement influencée par la pureté du dilactide de départ ainsi que par de la qualité du brassage et du temps de séjour. Ce projet a pour but de développer une méthode d'optimisation en ligne de la masse molaire du PLA obtenu par extrusion réactive en contrôlant «intelligemment» les paramètres de celle-ci. Ceci permettra de produire du PLA de masse molaire désirée.

Equipe de recherche au sein de la HES-SO: Kalman Franka , Dabros Michal , Sanglard Pauline , Vorlet Olivier , Audriaz Michel

Partenaires académiques: VS - Institut Technologies du vivant; FR - EIA - Institut ChemTech; Dabros Michal, FR - EIA - Institut ChemTech

Durée du projet: 01.03.2013 - 30.06.2014

Montant global du projet: 120'000 CHF

Statut: Terminé

2025

Digitised optimisation of nanoparticle synthesis via laser ablation :
Article scientifique ArODES
an industry 4.0 multivariate approach for enhanced production

Brian Freeland, Ronan McCann, Burcu Akkoyunlu, Manuel Tiefenthaler, Michal Dabros, Mandy Juillerat, Keith D. Rochfort, Greg Foley, Dermot Brabazon

Processes,  2025, 13, 2, 388

Lien vers la publication

Résumé:

The synthesis of nanoparticles (NPs) via laser ablation synthesis in solution (LASiS) is a promising method for sustainable and efficient nanoparticle fabrication. This work investigates the transition from one-factor-at-a-time experimentation to a more efficient, multivariate approach for optimising NP production efficiency. By applying the Industry 4.0 principles, the objective is to digitise and automate laboratory processes to increase productivity and robustness. Design of Experiments (DoE) strategies, Taguchi orthogonal arrays and full-factorial design (FFD), have been employed to enhance laser ablation processes. Both models confirmed that increasing laser power led to higher colloid absorbance, with the Taguchi DoE offering rapid initial process mapping and FFD providing a higher-resolution analysis. The optimal laser repetition rate of 30 kHz was identified as a balance between pulse energy and thermal effects on the target, maximising ablation efficiency. The Taguchi model had a prediction of NP size with an R2 value of 0.49, while the FFD struggled with accurate size prediction. Additionally, this study introduced a recirculation flow regime as a rapid test platform for predicting optimal conditions for continuous flow production. Using a semi-autonomous DoE platform decreased the operator involvement and increased the process selectivity. This proof-of-concept for on-the-bench NP rapid manufacturing demonstrated how efficient NP synthesis processes can be developed by clarifying the effects of varying parameters on colloid productivity, paving the way for broader industrial applications in the future.

2024

Brewer’s spent grain as a self-sufficient feedstock for homofermentative production of optically pure L-lactic acid using Lactobacillus rhamnosus
Article scientifique ArODES

Coralie Granget, n. Arul Manikandan, K. Amulya, Michal Dabros, Samantha Fahy, Susan M. Kelleher, Keith D. Rochfort, Jennifer Gaughran, Brian Freeland

Environmental Technology & Innovation,  34, 2024, 103582

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Résumé:

Brewer’s spent grain (BSG), accounting for 85% of the total by-product from breweries, was used as a feedstock for L-lactic acid production in the present study. BSG was enzymatically hydrolysed and promoted to be a self-sufficient feedstock for L-lactic acid production by using it as a sole source of carbon, protein and minerals. Process parameters like glucose concentration (10–20 g/L), glucose-to-protein source ratio (1:1 – 5:1), source of protein and inoculum concentration (3 – 10% v/v) were selected to divert the carbon source and enhance L-lactic acid concentration, which would otherwise result in bacterial biomass production. Yeast extract and whey permeate resulted in high bacterial growth, whereas self-sustained protein (SSP) in BSG resulted in higher L-lactic acid production. Further, the glucose-to-protein source ratio was maintained at its lowest level for better glucose conversion to L-lactic acid. Glucose concentration strongly influenced L-lactic acid production. Therefore glucose concentration in the batch fermentation process was further increased from 60 to 120 g/L. A maximum L-lactic acid concentration of 114.4 g/L and productivity of 5.14 g/L·h was achieved with an initial glucose concentration of 120 g/L, and the rest of the process parameters such as glucose to protein source ratio of 1:1, inoculum concentration of 10% v/v and SSP in BSG were maintained at its optimum level. Finally, L-lactic acid in the fermentation broth was purified and analysed for its similarity with commercially available L-lactic acid using proton-NMR and FTIR spectroscopy. Thus, the present study valorised BSG by producing L-lactic acid under a biorefinery approach.

Development of lab-scale continuous stirred-tank reactor as flow process tool for oxidation reactions using molecular oxygen
Article scientifique ArODES

Ursina Gnädinger, Dario Poier, Claudio Trombini, Michal Dabros, Roger Marti

Organic Process Research & Development,  2024, 28, 5, 1860-1868

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Résumé:

The use of sustainable oxidants is of great interest to the chemical industry, considering the importance of oxidation reactions for the manufacturing of chemicals and society’s growing awareness of its environmental impact. Molecular oxygen (O2), with an almost optimal atom efficiency in oxidation reactions, presents one of the most attractive alternatives to common reagents that are not only toxic in most cases but produce stoichiometric amounts of waste that must be treated. However, fire and explosion safety concerns, especially when used in combination with organic solvents, restrict its easy use. Here, we use state-of-the-art 3D printing and experimental feedback to develop a miniature continuous stirred-tank reactor (mini-CSTR) that enables efficient use of O2 as an oxidant in organic chemistry. Outstanding heat dissipation properties, achieved through integrated jacket cooling and a high surface-to-volume ratio, allow for a safe operation of the exothermic oxidation of 2-ethylhexanal, surpassing previously reported product selectivity. Moving well beyond the proof-of-concept stage, we characterize and illustrate the reactor’s potential in the gas–liquid–solid triphasic synthesis of an endoperoxide precursor of antileishmanial agents. The custom-designed magnetic overhead stirring unit provides improved stirring efficiency, facilitating the handling of suspensions and, in combination with the borosilicate gas dispersion plate, leading to an optimized gas–liquid interface. These results underscore the immense potential that lies within the use of mini-CSTR in sustainable chemistry.

2022

Thermal safety and structure-related reactivity investigation of five-membered cyclic sulfamidates
Article scientifique ArODES

Thomas Ferrari, Caitlin Blum, Lara Amini-Rentsch, Pierre Brodard, Michal Dabros, Pascale Hoehn, Aniko Udvarhelyi, Roger Marti, Michaël Parmentier

Organic Process Research Development,  2022, vol. 26, pp. 2614-2623

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Résumé:

Five-membered cyclic sulfamidates are very valuable electrophiles in organic synthesis and readily used on a multikilogram scale. However, their thermal degradation is underreported and might lead to unforeseen and undesirable safety events. In addition, ring or nitrogen substitution can have a tremendous influence on cyclic sulfamidate reactivity toward bases and therefore impact the overall safety assessment of a process. An understanding of such behavior is therefore of high importance in the industry while designing a synthetic route, as a change of, e.g., a protecting group can increase the thermal safety of a step on scale. We report herein the thermal degradation investigation as well as the structure-related reactivity exploration of cyclic sulfamidates, including their use in combination with strong bases. The design of a predictive model to rapidly assess the thermal hazard based on collected data and selected molecular descriptors is also presented.

Development, validation, and application of a custom-made mini-reaction calorimeter for thermal safety screening
Article scientifique ArODES

Caitlin Blum, Lara Amini-Rentsch, Thomas Ferrari, Pierre Brodard, Roger Marti, Pascale Hoehn, Michal Dabros, Michaël Parmentier

Organic Process Research Development,  2022, vol. 26, no. 9, pp. 2624-2628

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Résumé:

Before scaling up to production, it is of high importance to evaluate the potential of a reaction to lead to an undesired thermal degradation event. The use of a large amount of compounds is usually required for a reliable calorimetry study. In this work, we report the development of a milliliter-scale reaction calorimeter for reaction screening applications. The setup was designed using laboratory equipment and characterized and validated with routine experiments. The results were sufficiently accurate enabling us to observe trends in the measured reaction enthalpies of a family of compounds reacting with strong bases as a function of the compounds' structures.. The use of the microscale tailor-made calorimeter is considered very valuable for potentially highly energetic reactions since reaction calorimetry studies can be performed accurately and safely with small amounts of valuable materials.

A review of polylactic acid as a replacement material for single-use laboratory components
Article scientifique ArODES

Brian Freeland, Eanna McCarthy, Rengesh Balakrishnan, Samantha Fahy, Adam Boland, Keith D. Rochfort, Michal Dabros, Roger Marti, Susan M. Kelleher, Jennifer Gaughran

Materials,  2022, vol. 15, no. 9, article no. 2989

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Résumé:

Every year, the EU emits 13.4 Mt of CO2 solely from plastic production, with 99% of all plastics being produced from fossil fuel sources, while those that are produced from renewable sources use food products as feedstocks. In 2019, 29 Mt of plastic waste was collected in Europe. It is estimated that 32% was recycled, 43% was incinerated and 25% was sent to landfill. It has been estimated that life-sciences (biology, medicine, etc.) alone create plastic waste of approximately 5.5 Mt/yr, the majority being disposed of by incineration. The vast majority of this plastic waste is made from fossil fuel sources, though there is a growing interest in the possible use of bioplastics as a viable alternative for single-use lab consumables, such as petri dishes, pipette tips, etc. However, to-date only limited bioplastic replacement examples exist. In this review, common polymers used for labware are discussed, along with examining the possibility of replacing these materials with bioplastics, specifically polylactic acid (PLA). The material properties of PLA are described, along with possible functional improvements dure to additives. Finally, the standards and benchmarks needed for assessing bioplastics produced for labware components are reviewed.

Fed-batch system for propagation of brewer’s yeast
Article scientifique ArODES

Dan Donnelly, Lucien Blanchard, Michal Dabros, Seamus O'Hara, Dermot Brabazon, Greg Foley, Brian Freeland

Journal of the American Society of Brewing Chemists,  2022, vol. 80, no. 2, pp. 190-200

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Résumé:

A novel high-density yeast propagation system has been developed, which produced yeast that performed as well as cropped yeast in commercial brewery trials. This process is capable of producing yeast concentrations 13 times greater than traditional yeast propagation approaches used in breweries to date. The system is based on a controlled fed-batch yeast fermentation, which can produce pitching yeast in as little as 24 h. A demonstrator plant was installed in a regional brewery and yeast produced from the test-platform was used to pitch commercial brews. Plant-scale trials have shown that the yeast propagated using this new system had the same fermentation profile compared to control fermentations that used cropped yeast. Volatile analysis showed no significant difference between the control and experimental beers. The experimental beers tasted true-to-type and were released to trade. The new process allows for smaller pitching volumes while maintaining overall beer quality.

2021

Novel Strategy for the Calorimetry-Based Control of Fed-Batch Cultivations of Saccharomyces cerevisiae
Article scientifique ArODES

Jérémy Kottelat, Brian Freeland, Michal Dabros

Processes,  2021, vol. 9, no. 4, article no. 723

Lien vers la publication

Résumé:

Typical controllers for fed-batch cultivations are based on the estimation and control of the specific growth rate in real time. Biocalorimetry allows one to measure a heat signal proportional to the substrate consumed by cells. The derivative of this heat signal is usually used to evaluate the specific growth rate, introducing noise to the resulting estimate. To avoid this, this study investigated a novel controller based directly on the heat signal. Time trajectories of the heat signal setpoint were modelled for different specific growth rates, and the controller was set to follow this dynamic setpoint. The developed controller successfully followed the setpoint during aerobic cultivations of Saccharomyces cerevisiae, preventing the Crabtree effect by maintaining low glucose concentrations. With this new method, fed-batch cultivations of S. cerevisiae could be reliably controlled at specific growth rates between 0.075 h−1 and 0.20 h−1, with average root mean square errors of 15 ± 3%.

Real-time monitoring and control for high-efficiency autonomous laser fabrication of silicon nanoparticle colloids
Article scientifique ArODES

Brian Freeland, Ronan McCann, Paul O'Neill, Sithara Sreenilayam, Manuel Tiefenthaler, Michal Dabros, Mandy Juillerat, Greg Foley, Dermot Brabazon

The International Journal of Advanced Manufacturing Technology,  2021, vol. 114, pp. 291-304

Lien vers la publication

Résumé:

Nanotechnology is a significant research tool for biological and medical research with major advancements achieved from nanoparticle (Np) applications in biosensing and biotherapeutics. For laser ablation synthesis in solution (LASiS) to be chosen by researchers for Np colloid production, the process must effectively compete with chemical synthesis in terms of produced colloid quality and productivity while taking advantage of LASiS benefits in terms of its ‘green-synthesis’ and single-step functionalisation abilities. In this work, a newly developed integrated LASiS Np manufacturing system is presented including a Np flow reactor design, an at-line Np size monitoring via 180° dynamic light scattering, and a UV-Vis spectroscopy system used to estimate colloid concentration and stability. The experimental outcomes are discussed in terms of Np productivity and quality via these at-line measurements from the UV-Vis and DLS systems. The developed instrument was validated via off-line SiNps DLS, UV-Vis and morphology tests via TEM. Ultra-high quality and nanoparticle fabrication rate efficiency was achieved and is reported here.

Distance teaching in chemistry :
Article scientifique ArODES
opportunities and limitations

Véronique Breguet Mercier, Ulrich Scholten, Richard Baltensperger, Ludovic Gremaud, Michal Dabros

CHIMIA International Journal for Chemistry,  2021, vol. 75, no. 1/2, pp. 58-63

Lien vers la publication

Résumé:

Remote teaching in the tertiary education sector is a relatively common practice, and the implementation of digital solutions in chemistry teaching offers many new opportunities and tools. A survey was conducted after 3 months of emergency remote teaching linked to the COVID-19 pandemic and showed that half of the students estimated it was difficult to study remotely, and reported they had to invest more time compared to classroom teaching, which led to a drop in motivation. Professors also noted that the time necessary to invest in order to produce digital teaching content was enormous. Massive open online laboratories (MOOLs) and process simulators are interesting tools, but practical lab work and related know-how cannot fully be replaced by digital techniques. Finally, it appeared that the professor–student interaction is very important in the distance-learning process, and that a high level of pedagogical (inter)activity is mandatory to maintain motivation and better quality of teaching and learning.

2020

Analytical platforms at swiss universities of applied sciences
Article scientifique ArODES

Christian Berchtold, Verena Christen, Jean-Pascal Bourgeois, Michal Dabros, Olivier Nicolet, Cyril Portmann, Samuel Roth, Olivier Vorlet, Caspar Demuth, Susanne Kern, Chahan Yeretzian, Anika Hoffmann, Franka Kalman, Nadia Marcon, Marc E. Pfeifer, Umberto Piantini, Denis Prim, Jean-Manuel Segura, Mathieu Zollinger, Götz Schlotterbeck

CHIMIA International Journal for Chemistry,  2020, vol. 74, no. 7/8, pp. 618-628

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Résumé:

Numerous projects and industrial and academic collaborations benefit from state-of-the-art facilities and expertise in analytical chemistry available at the Swiss Universities of Applied Sciences. This review summarizes areas of expertise in analytical sciences at the University of Applied Sciences and Arts Northwestern Switzerland (FHNW), the University of Applied Sciences and Arts Western Switzerland (HES-SO), and the Zurich University of Applied Sciences (ZHAW). We briefly discuss selected projects in different fields of analytical sciences

Control of specific growth rate in fed-batch bioprocesses :
Article scientifique ArODES
novel controller design for improved noise management

Yann Brignoli, Michal Dabros, Brian Freeland, David Cunningham

Processes,  2020, vol. 8(6), no. 679

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Résumé:

Accurate control of the specific growth rate (µ) of microorganisms is dependent on the ability to quantify the evolution of biomass reliably in real time. Biomass concentration can be monitored online using various tools and methods, but the obtained signal is often very noisy and unstable, leading to inaccuracies in the estimation of μ. Furthermore, controlling the growth rate is challenging as the process evolves nonlinearly and is subject to unpredictable disturbances originating from the culture’s metabolism. In this work, a novel feedforward-feedback controller logic is presented to counter the problem of noise and oscillations in the control variable and to address the exponential growth dynamics more effectively. The controller was tested on fed-batch cultures of Kluyveromyces marxianus, during which μ was estimated in real time from online biomass concentration measurements obtained with dielectric spectroscopy. It is shown that the specific growth rate can be maintained at different setpoint values with an average root mean square control error of 23 ± 6%

Analytical Platforms at Swiss Universities of Applied Sciences
Article professionnel

Christian Berchtold, Jean-Pascal Bourgeois, Verena Christen, Dabros Michal, Caspar Demuth, Hoffmann Anika, Kalman Franka, Susanne Kern, Marcon Nadia, Nicolet Olivier, Pfeifer Marc Emil, Umberto Piantini, Prim Denis, Portmann Cyril, Samuel Roth, Segura Jean-Manuel, Vorlet Olivier, Chahan Yeretzian, Mathieu Zollinger, Götz Schlotterbeck

Chimia, 2020 , vol.  74, no  7/8, pp.  618-628

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2019

Materials science at Swiss Universities of Applied Sciences
Article scientifique ArODES

Pierre Brodard, Michal Dabros, Roger Marti, Ennio Vanoli, Manfred Zinn, Urban Frey, Christian Adlhart, Lucy Kind, Franziska Koch, Floriana Burgio, Johan Stenqvist, Sina Saxer, Uwe Pieles, Patrick Shahgaldian, Sebastian Wendeborn

CHIMIA International Journal for Chemistry,  2019, vol. 73, no. 7/8, pp. 645-655

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Résumé:

In the Swiss Universities of Applied Sciences, several research institutes are involved in Materials Science, with different approaches and applications fields. A few examples of recent projects from different groups of the University of Applied Sciences and Arts Western Switzerland (HESSO), the Zurich University of Applied Sciences (ZHAW) and the University of Applied Sciences and Arts Northwestern Switzerland (FHNW) are given.

Continuous monitoring of shelf lives of materials by application of data loggers with implemented kinetic parameters
Article scientifique ArODES

Bertrand Roduit, Charles Albert Luyet, Marco Hartmann, Patrick Folly, Alexandre Sarbach, Alain Dejeaifve, Rowan Dobson, Nicolas Schroeter, Olivier Vorlet, Michal Dabros, Richard Baltensperger

Molecules,  2019, vol. 24, no. 12, article no 2217

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Résumé:

The evaluation of the shelf life of, for example, food, pharmaceutical materials, polymers, and energetic materials at room or daily climate fluctuation temperatures requires kinetic analysis in temperature ranges which are as similar as possible to those at which the products will be stored or transported in. A comparison of the results of the evaluation of the shelf life of a propellant and a vaccine calculated by advanced kinetics and simplified 0th and 1st order kinetic models is presented. The obtained simulations show that the application of simplified kinetics or the commonly used mean kinetic temperature approach may result in an imprecise estimation of the shelf life. The implementation of the kinetic parameters obtained fromadvanced kinetic analyses into programmable data loggers allows the continuous online evaluation and display on a smartphone of the current extent of the deterioration of materials. The proposed approach is universal and can be used for any goods, any methods of shelf life determination, and any type of data loggers. Presented in this study, the continuous evaluation of the shelf life of perishable goods based on the Internet of Things (IoT) paradigm helps in the optimal storage/shipment and results in a significant decrease of waste.

2018

Preventing overflow metabolism in crabtree-positive microorganisms through on-line monitoring and control of fed-batch fermentations
Article scientifique ArODES

Loïc Habegger, Kelly Rodrigues Crespo, Michal Dabros

Fermentation,  2018, 4, 3, 79

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Résumé:

At specific growth rates above a particular critical value, Crabtree-positive microorganisms exceed their respiratory capacity and enter diauxic growth metabolism. Excess substrate is converted reductively to an overflow metabolite, resulting in decreased biomass yield and productivity. To prevent this scenario, the cells can be cultivated in a fed-batch mode at a growth rate maintained below the critical value, µcrit. This approach entails two major challenges: accurately estimating the current specific growth rate and controlling it successfully over the course of the fermentation. In this work, the specific growth rate of S. cerevisiae and E. coli was estimated from enhanced on-line biomass concentration measurements obtained with dielectric spectroscopy and turbidity. A feedforward-feedback control scheme was implemented to maintain the specific growth rate at a setpoint below µcrit, while on-line FTIR measurements provided the early detection of the overflow metabolites. The proposed approach is in line with the principles of Bioprocess Analytical Technology (BioPAT), and provides a means to increase the productivity of Crabtree-positive microorganisms.

2016

On-line monitoring and control of fed-batch fermentations in winemaking
Article scientifique ArODES

Michal Dabros, Giorgio Genasci, Julien Blanchard, Samuel Unterhofer, Olivier Vorlet, Ramon Mira de Orduña Heidinger, Jean-Pascal Bourgeois

CHIMIA International Journal for Chemistry,  2016, vol. 70, no. 12, pp. 900-901

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Résumé:

The fermentation of yeast in fed-batch mode shows great potential in winemaking because it allows the concentration of sugars to be kept low and constant throughout the process which, in turn, reduces cell stress and leads to a significant decrease in the production of unwanted secondary metabolites. The implementation of this technique requires reliable on-line analysis of sugar and a robust control strategy to maintain sugar concentrations at defined levels over the course of the fermentation. In this study, a laboratory-scale setup was used to implement and assess a fully automated fed-batch fermentation of Saccharomyces cerevisiae in grape must. Total sugar levels were monitored in-line by FT-MIR ATR spectroscopy and kept constant at 50 g/kg by a modified PI controller regulating the must feed flow rate. Good setpoint tracking and disturbance rejection were achieved in fermentations of up to four days despite occasional yeast sedimentation on the ATR crystal. The controller parameter adaptation strategy needs to be optimized for longer fermentations.

Reactor dynamics investigation based on calorimetric data
Article scientifique ArODES

Charles Guinand, Michal Dabros, Thierry Meyer, Francis Stoessel

The Canadian Journal of Chemical Engineering,  2016, vol. 95, no. 2

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Résumé:

A simple and general procedure has been developed to determine the thermal behaviour of a reactor based on heat balance, PID temperature control, and jacket behaviour. Using only temperature heating/cooling ramps followed by isothermal stages, such a procedure was tested at laboratory and industrial scale, respectively in a 0.5 L Mettler‐Toledo RC1e and a 100 L industrial reactor. The obtained model was demonstrated to be in good accordance with the measurements. The consistency and robustness of the model were assessed by imposing an external heat profile based on an autocatalytic reaction system. The results have proven that even under perturbations, the retrieved parameters remain correct. In summary, the thermal behaviour of a chemical reactor can be defined through the reactor dynamic investigation procedure and can be used to identify the optimal operating conditions.

International relations at universities of applied sciences
Article professionnel ArODES

Roger Marti, Michal Dabros, Uwe Pieles, Urban Frey, Achim Ecker

CHIMIA International Journal for Chemistry,  2016, vol. 70, no. 7, pp. 555-556

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Résumé:

An overview of international relations at the Universities of Applied Sciences in Switzerland is presented.

Thermal process safety based on reaction kinetics and reactor dynamics
Article scientifique ArODES

Charles Guinand, Michal Dabros, Bertrand Roduit, Thierry Meyer, Francis Stoessel

Chemical Engineering Transactions (CEt),  2016, vol. 48, pp. 19-24

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Résumé:

The specific problem of non-converted reactant accumulation encountered in fed-batch reactor is a challenging task of process safety. In order to avoid such situation that may lead to a runaway reaction, the reaction kinetics and reactor dynamic must be known. In this work, an innovative approach to determine an optimal feed profile, based on a reaction kinetic and reactor dynamic, is presented. This approach was applied to the reaction system involved in the Morton International Inc. incident. Great improvements were observed in the control of the accumulation, decreasing the number of necessary experiments needed for the scale-up studies.

2015

PAT at the Universities of Applied Sciences
Article scientifique ArODES

Michal Dabros, Olivier Vorlet, Roger Marti, Wolfgang Riedl, Gerhard Grundler, Aldo Vaccari, Manfred Zinn, Achim Ecker, Christian Hinderling

CHIMIA International Journal of Chemistry,  2015, vol. 69, no. 7/8, pp. 482-484

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Résumé:

An overview of activities in the field of Process Analytical Technologies (PAT) at the Universities of Applied Sciences in Switzerland is presented.

2014

Optimization of chemical reactor feed by simulations based on a kinetic approach
Article professionnel ArODES

Charles Guinand, Michal Dabros, Bertrand Roduit, Thierry Meyer, Francis Stoessel

CHIMIA,  2014, vol. 68, no. 10, pp. 746-747

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Résumé:

Chemical incidents are typically caused by loss of control, resulting in runaway reactions or process deviations in different stages of the production. In the case of fed-batch reactors, the problem generally encountered is the accumulation of heat. This is directly related to the temperature of the process, the reaction kinetics and adiabatic temperature rise, which is the maximum temperature attainable in the event of cooling failure. The main possibility to control the heat accumulation is the use of a well-controlled adapted feed. The feed rate can be adjusted by using reaction and reactor dynamic models coupled to Model Predictive Control. Thereby, it is possible to predict the best feed profile respecting the safety constraints.

Yeast Suspension culture.
Article scientifique
Industrial Scale Suspension Culture of Living Cells.

Jungo Rhême Carmen, D. Mattanovich, J. Wenger, Dabros Michal, M. Maurer

Book in Wiley VCH Verlag GmBh & Co. KGaA, 2014 , pp.  94-129

2023

Biocalorimetry as a Process Analytical Technology (PAT) tool
Conférence

Dabros Michal

Annual Meeting, Swiss Society of Thermal Analysis and Calorimetry (STK 2023), 19.10.2023 - 19.10.2023, La Tour-de-Peilz, Switzerland

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Projets de coopération internationale à l’Institut ChemTech, HEIA-FR (Suisse)
Conférence

Dabros Michal, Vorlet Olivier

Colloque international sur le Génie humanitaire, 05.04.2023 - 05.04.2023, Polytechnique Montréal, Canada & on-line

Biocalorimetry as a Process Analytical Technology (PAT) tool
Conférence

Dabros Michal

SGVC - Calorimetry Beyond Safety, 31.01.2023 - 31.01.2023, Fribourg, Switzerland

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2022

Process Analytical Technology (PAT) – Background & Applications in Flow Chemistry
Conférence

Dabros Michal

Swiss Chemical Society – Seminar on Flow Chemistry, 27.06.2022 - 29.06.2022, Villars-sur-Glâne, Switzerland

2021

Chemometric modelling of thermal properties
Conférence
Invited talk

Dabros Michal, Anikó Udvarhelyi

Annual Meeting, Swiss Society of Thermal Analysis and Calorimetry (STK 2021), 26.10.2021 - 26.10.2021, Fribourg, Switzerland

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2018

Preventing overflow metabolism in Crabtree-positive microorganisms using the PAT approach: progress and challenges
Conférence

Dabros Michal

Forum on Process Analytical Technology (PAT), ILMAC, 03.10.2018 - 03.10.2018, Lausanne, Switzerland

2017

Specific biomass growth rate estimation and control using on-line bioprocess monitoring
Conférence
Keynote lecture

Dabros Michal

5th Bioprocessing India Conference, 09.12.2017 - 11.12.2017, IIT-Guwahati, India

Control and optimal run of batch distillations
Conférence

Dabros Michal

SGVC – Latest Advances in Chemical Engineering, 16.11.2017 - 16.11.2017, Basel, Switzerland

Specific biomass growth rate estimation and control using on-line bioprocess monitoring
Conférence

Dabros Michal

BioTech 2017, 07.09.2017 - 08.09.2017, Wädenswil, Switzerland

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