Publications by Urs von Stockar

Optimal energy dissipation in growing microorganisms and rectification columns

This paper proposes a new point of view in analyzing the optimal Gibbs energy dissipation in growing microorganisms. Small Gibbs energy dissipation in growth would be of biological advantage because less resource is consumed and the biomass yield on these ...

De Gruyter2014

The role of thermodynamics in biochemical engineering

Urs von Stockar

This article is an adapted version of the introductory chapter of a book whose publication is imminent. It bears the title "Biothermodynamics - The role of thermodynamics in biochemical engineering." The aim of the paper is to give a very short overview of ...

De Gruyter2013

Calorimetry and thermodynamic aspects of heterotrophic, mixotrophic, and phototrophic growth

Ian William Marison, Urs von Stockar

A simple stoichiometric model is proposed linking the biomass yield to the enthalpy and Gibbs energy changes in chemo-heterotrophic, mixotrophic, and photo-autotrophic microbial growth. A comparison with calorimetric experiments on the algae Chlorella vulg ...

2011

Biothermodynamics of live cells: a tool for biotechnology and biochemical engineering

Urs von Stockar

The aim of this contribution is to review the application of thermodynamics to live cultures of microbial and other cells and to explore to what extent this may be put to practical use. A major focus is on energy dissipation effects in industrially relevan ...

De Gruyter2010

Removal of pharmaceuticals from water: Using liquid-core microcapsules as a novel approach

Ian William Marison, Urs von Stockar

In recent years ever-increasing amounts of pharmaceuticals are being detected in the aquatic environment and in some cases, they have even been discovered in drinking water. Their presence is attributed mainly to the inability of sewage treatment plants to ...

2010

Data Reconciliation of Concentration Estimates from Mid-Infrared and Dielectric Spectral Measurements for Improved On-Line Monitoring of Bioprocesses

Michael Amrhein, Dominique Bonvin, Ian William Marison, Urs von Stockar, Michal Dabros

Real-time data reconciliation of concentration estimates of process analytes and biomass in microbial fermentations is investigated. A Fourier-transform mid-infrared spectrometer predicting the concentrations of process metabolites is used in parallel with ...

2009

Cole-Cole, linear and multivariate modeling of capacitance data for on-line monitoring of biomass

Ian William Marison, Urs von Stockar, Danielle Dennewald, Michal Dabros

This work evaluates three techniques of calibrating capacitance (dielectric) spectrometers used for on-line monitoring of biomass: modeling of cell properties using the theoretical Cole-Cole equation, linear regression of dual-frequency capacitance measure ...

Springer-Verlag2009

Influence of Uncertainties in pH, pMg, Activity Coefficients, Metabolite Concentrations, and Other Factors on the Analysis of the Thermodynamic Feasibility of Metabolic Pathways

Urs von Stockar

Thermodynamic feasibility analysis (TFA) has been used as a toot capable of providing additional constraints to the mass balance-based methods of analysis of Metabolic networks (e.g., flux balance analysis). Several publications have recently appeared in w ...

2009

Can microbial growth yield be estimated using simple thermodynamic analogies to technical processes?

Urs von Stockar

In view of the prime importance of the biomass yield in microbial growth for research, for environmental and for industrial applications some thermodynamic concepts are reviewed that were developed over the years in order to understand the large variations ...

2008

Influence of specific growth rate on specific productivity and glycosylation of a recombinant avidin produced by a Pichia pastoris Mut(+) strain

Ian William Marison, Urs von Stockar, Jonas Schenk, Carmen Jungo, Julien Urfer, Carole Wegmann, Krisztina Balàzs

A recombinant avidin-producing Mut(+) Pichia pastoris strain was used as a model organism to study the influence of the methanol feeding strategy on the specific product productivity (q(p)) and protein glycosylation. Fed-batch cultivations performed at var ...

2008

On-line monitoring of nine different batch cultures of E-coli by mid-infrared spectroscopy, using a single spectra library for calibration

Ian William Marison, Urs von Stockar, Jonas Schenk, Carla Viscasillas Nadal

A single spectra library was used to monitor on-line, by mid-infrared spectroscopy, nine different batch cultures of Escherichia coli performed with various medium compositions, including chemically complex formulations. Whereas the classic chemometrics ap ...

2008

Immobilization of rapeseed press-cake in an alginate matrix for the sorption of atrazine

Ian William Marison, Urs von Stockar, Julien Boucher, Véronique Breguet

Due to residual oil retained within it, rapeseed press-cake has been shown to be effective for the removal of atrazine from water through an absorption mechanism. However, it is difficult to put this into practice due to the hygroscopic nature of the press ...

2008

Enzymatic hydrolysis of organic-core microcapsules to produce aqueous-core microcapsules

Ian William Marison, Urs von Stockar, Véronique Breguet

This paper describes the development of a new method to obtain aqueous-core microcapsules from organic-core capsules. The direct production of microcapsules, using tripropionin as organic material, followed by the hydrolysis of the core by a lipase was inv ...

2008

CHO immobilization in alginate/poly- l -lysine microcapsules: an understanding of potential and limitations

Raphaël Gugerli, Ian William Marison, Urs von Stockar, Véronique Breguet

Springer, Springer Netherlands2007

A quantitative analysis of the benefits of mixed feeds of sorbitol and methanol for the production of recombinant avidin with Pichia pastoris

Ian William Marison, Urs von Stockar, Jonas Schenk, Carmen Jungo, Muriel Pasquier

2007

Mixed feeds of glycerol and methanol can improve the performance of Pichia pastoris cultures: A quantitative study based on concentration gradients in transient continuous cultures

Ian William Marison, Urs von Stockar, Carmen Jungo

2007

Simplified Fourier-transform mid-infrared spectroscopy calibration based on a spectra library for the on-line monitoring of bioprocesses

Ian William Marison, Urs von Stockar, Jonas Schenk

2007

On-Line Recalibration of Spectral Measurements Using Metabolite Injections and Dynamic Orthogonal Projection

Michael Amrhein, Urs von Stockar, Michal Dabros, Pamandeep Singh Gujral

Spectrometers are enjoying increasing popularity in bioprocess monitoring due to their non-invasiveness and in-situ sterilizability. Their on-line applicability and high measurement frequency create an interesting opportunity for process control and optimi ...

2007

Optimisation of culture conditions with respect to biotin requirement for the production of recombinant avidin in Pichia pastoris

Ian William Marison, Urs von Stockar, Carmen Jungo, Julien Urfer

2007

A simple method to monitor and control methanol feeding of Pichia pastoris fermentations using mid-IR spectroscopy

Ian William Marison, Urs von Stockar, Jonas Schenk

2007