TY - JOUR
T1 - Use of equivalent circuit analysis and Cole–Cole model in evaluation of bioreactor operating conditions for biomass monitoring by impedance spectroscopy
AU - Díaz Pacheco, Adrián
AU - Delgado-Macuil, Raul Jacobo
AU - Díaz-Pacheco, Ángel
AU - Larralde-Corona, Claudia Patricia
AU - Dinorín-Téllez-Girón, Jabel
AU - López-Y-López, Victor Eric
N1 - Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2021/9
Y1 - 2021/9
N2 - The most important parameter in bioprocesses is biomass, where not only the quantity produced in a culture but also the behavior that is presented are important concerns. It is clear that conditions of operation in a bioreactor affect biomass production, but how operation conditions affect the measurement of biomass on-line is of special interest. We studied the effect of bioreactor operating condition variations on model parameters using impedance spectroscopy for biomass monitoring. The model parameters analyzed were capacitance, resistance, alpha (α), conductivity delta (∆σ) and critical frequency (fc). These model parameters were obtained by fitting data from impedance measurements to an equivalent circuit model and Cole–Cole conductivity model. The effect of operating conditions on the medium with no cells was estimated by the percentage of change in each model parameter. The operating conditions with the most significant percentage of change were determined, by comparing to the percentage of change of the same model parameters obtained, during a fermentation of Bacillus thuringiensis as a cellular model. Equivalent circuit parameters were mainly affected by variation in pH, temperature and aeration, whereas Cole–Cole parameters were affected by variation in agitation, aeration, temperature and pH. Therefore, any variation in these operating conditions (within the test interval) during a fermentation may generate changes in monitoring parameters, which will not be a direct consequence of any change in the properties of the biomass.
AB - The most important parameter in bioprocesses is biomass, where not only the quantity produced in a culture but also the behavior that is presented are important concerns. It is clear that conditions of operation in a bioreactor affect biomass production, but how operation conditions affect the measurement of biomass on-line is of special interest. We studied the effect of bioreactor operating condition variations on model parameters using impedance spectroscopy for biomass monitoring. The model parameters analyzed were capacitance, resistance, alpha (α), conductivity delta (∆σ) and critical frequency (fc). These model parameters were obtained by fitting data from impedance measurements to an equivalent circuit model and Cole–Cole conductivity model. The effect of operating conditions on the medium with no cells was estimated by the percentage of change in each model parameter. The operating conditions with the most significant percentage of change were determined, by comparing to the percentage of change of the same model parameters obtained, during a fermentation of Bacillus thuringiensis as a cellular model. Equivalent circuit parameters were mainly affected by variation in pH, temperature and aeration, whereas Cole–Cole parameters were affected by variation in agitation, aeration, temperature and pH. Therefore, any variation in these operating conditions (within the test interval) during a fermentation may generate changes in monitoring parameters, which will not be a direct consequence of any change in the properties of the biomass.
KW - Bacillus thuringiensis
KW - Bioreactors
KW - Cole–Cole
KW - Impedance spectroscopy
KW - Operating conditions
KW - Zarc circuit
UR - http://www.scopus.com/inward/record.url?scp=85104957427&partnerID=8YFLogxK
U2 - 10.1007/s00449-021-02572-0
DO - 10.1007/s00449-021-02572-0
M3 - Artículo
C2 - 33884467
AN - SCOPUS:85104957427
SN - 1615-7591
VL - 44
SP - 1923
EP - 1934
JO - Bioprocess and Biosystems Engineering
JF - Bioprocess and Biosystems Engineering
IS - 9
ER -