Automated algorithm to determine kLa considering system delay

BACKGROUND Quantification of the volumetric oxygen transfer coefficient (kLa) is essential to characterize and optimize the oxygen transfer capacity of bioreactors. First order methodologies are commonly used to estimate kLa; however, when the delay of the system cannot be neglected, second‐order me...

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Bibliographic Details
Published in:Journal of chemical technology and biotechnology (1986) 2017-07, Vol.92 (7), p.1630-1637
Main Authors: Torres, Paulina, Cerri, Marcel Otavio, de Arruda Ribeiro, Marcelo Perencin, Pérez‐Correa, J Ricardo, Agosin, Eduardo
Format: Article
Language:English
Subjects:
Aeration
Agitation
Algorithms
automated volumetric oxygen transfer coefficient estimation
Automation
Bioreactors
Data smoothing
Delay
gassing‐out method
Intervention
Oxygen
Oxygen transfer
system delay
Viscosity
volumetric oxygen transfer coefficient
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Summary:BACKGROUND Quantification of the volumetric oxygen transfer coefficient (kLa) is essential to characterize and optimize the oxygen transfer capacity of bioreactors. First order methodologies are commonly used to estimate kLa; however, when the delay of the system cannot be neglected, second‐order methodologies are required for accurate estimations. Second‐order methods are time consuming and hard to reproduce. In this study, we describe an automated algorithm to estimate kLa in conventional bioreactors. RESULTS The simple, four step algorithm developed considers: (1) data smoothing; (2) selection of a high oxygen variation zone; (3) selection of the time period where the instantaneous kLa is constant; and (4) kLa estimation. The algorithm was coded in MATLAB and four adjustable parameters were fixed heuristically using eight response curves with different hydrodynamic conditions (varying viscosity, agitation and aeration). Compared with manual processing, 80 validation experiments showed that the proposed automatic algorithm yields much more reproducible results in a fraction of the manual processing time. CONCLUSION The algorithm is fast and yields, without human intervention, reliable kLa estimations under different hydrodynamic conditions; hence, it is useful for designing high throughput kLa assessment systems to optimize oxygen delivery in bioreactors. © 2016 Society of Chemical Industry
ISSN:0268-2575
1097-4660
DOI:10.1002/jctb.5157