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Aberystwyth, United Kingdom

Kedia G.,University of South Wales | Passanha P.,University of South Wales | Dinsdale R.M.,University of South Wales | Guwy A.J.,University of South Wales | And 2 more authors.
Bioresource Technology | Year: 2013

In this study, dielectric spectroscopy was utilised to evaluate and define the optimum harvesting time for polyhydroxyalkanoates (PHA) production. It is essential to harvest PHA at the optimum time during fermentation for maximum yield, otherwise cells start degrading. Two carbon sources (acetic and butyric acids) were used in laboratory based experiments and a number of samples were measured ex situ for PHA production. The real-time measured capacitance in addition of identifying the cells growth phase, it correlated very well with ex situ measured PHA produced within the cells. The probe has proven to be a useful tool to assess process kinetics, to monitor real-time cell growth, PHA produced and defining the optimum harvesting time. © 2013 Elsevier Ltd.

Aber Instruments Ltd | Date: 2005-09-13

Cell culture monitors; viable cell monitors; apparatus, namely, biomass monitors and biomass sensors for measurement of biomass; measurement apparatus, namely, yeast monitors, probes for yeast monitors, and laboratory yeast analysers; yeast analysers; yeast pitching apparatus, namely, yeast monitors for the control of control switches; yeast cropping apparatus, namely, yeast monitors for the control of introductions of liquids bearing yeast into settling and storage vessels; control systems for the aforesaid goods, namely, computers and computer software for the control and monitoring of yeast monitors, biomass monitors, and biomass sensors; parts and fittings for the aforesaid goods.

Aber Instruments Ltd | Date: 2013-03-01

Yeast pitching apparatus, namely, yeast monitor, piping, valves, flow meter, frame, control electronics, cables, transmitters, probes and electrodes; yeast measurement apparatus, namely, yeast monitor, piping, valves, flow meter, frame, control electronics, cables, transmitters, probes and electrodes; electronic control systems for the aforesaid goods; parts and fittings for the aforesaid goods.

Aber Instruments Ltd | Date: 2011-07-07

A method of dealing with the electrode polarization error when analyzing a dielectric test medium is achieved by firstly applying an excitation current to the test medium at a test frequency, by means of a first electric couple (

Lee H.W.,Clinical Drug Manufacturing Center | Carvell J.,Aber Instruments Ltd. | Brorson K.,U.S. Food and Drug Administration | Yoon S.,University of Massachusetts Lowell
Journal of Chemical Technology and Biotechnology | Year: 2015

BACKGROUND: In mammalian cell culture processes, viable cell density (VCD) is one of the most crucial parameters for monitoring of the current status of cell growth and protein production. Among the various real-time monitoring tools available for VCD in Chinese hamster ovary (CHO) cell culture, dielectric spectroscopy is one of the more reliable due to its simplicity, robustness and accuracy. These attributes enable efficient monitoring and control of the corresponding processes. However, one of the major drawbacks of dielectric spectroscopy is frequent deterioration of accuracy during the late-growth phase of CHO cell culture. This can be caused by abrupt changes in the cell physiology, as well as environmental conditions. RESULTS: In this study, various kinds of chemometric tools were employed to understand the spectral dynamics of dielectric spectroscopy during extended CHO cell culture, including different cell growth phases. Then, the performance of different multivariate regression models were compared with conventional Cole-Cole equation-based approaches. The models were compared in their ability to estimate VCD in CHO cell culture from dielectric spectra from several batches of bioreactor operations. Multivariate analysis of dielectric spectral datasets clearly revealed the time-varying evolution of spectral dynamics during the transition between cell growth phases. The best prediction performance from the dielectric spectroscopy was realized using a regression model based on locally-weighted partial least squares (LWPLS). This estimation model best compensated for spectral dynamics observed during the different cell growth phases. CONCLUSION: Dielectric spectroscopy combined with LWPLS allows achievement of optimal and stable estimation of VCD during CHO cell culture, regardless of inherent differences in cell growth phases. © 2014 Society of Chemical Industry.

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