On-line biomass measurements in bioreactor cultivations: comparison study of two on-line probes

Two on-line probes for biomass measurement in bioreactor cultivations were evaluated. One probe is based on near infrared (NIR) light absorption and the other on dielectric spectroscopy. The probes were used to monitor biomass production in cultivations of several different microorganisms. Differences in NIR probe response compared to off-line measurement methods revealed that the most significant factor affecting the response was cell shape. The NIR light absorption method is more developed and reliable for on-line in situ biomass estimation than dielectric spectroscopy. The NIR light absorption method is, however, of no significant use, when the cultivation medium is not clear, and especially in processes using adsorbents or solid matrix for the microorganism to grow on. The possibilities offered by dielectric spectroscopy are impressive, but the on-line probe technology needs to be improved.

[1]  C. Will Chen,et al.  Bounded water kinetic model of β-galactosidase in reverse micelles , 2004 .

[2]  S. Arnold,et al.  Use of at‐line and in‐situ near‐infrared spectroscopy to monitor biomass in an industrial fed‐batch Escherichia coli process , 2002, Biotechnology and bioengineering.

[3]  J. Nielsen,et al.  On-line and in situ monitoring of biomass in submerged cultivations , 1997 .

[4]  Sing Kiong Nguang,et al.  Soft sensors for on-line biomass measurements , 2004, Bioprocess and biosystems engineering.

[5]  E. Gheorghiu,et al.  Real-time monitoring of yeast cell division by dielectric spectroscopy. , 1999, Biophysical journal.

[6]  Christopher L. Davey,et al.  The dielectric properties of biological cells at radiofrequencies : Applications in biotechnology , 1999 .

[7]  Urs von Stockar,et al.  On‐line biomass monitoring of CHO perfusion culture with scanning dielectric spectroscopy , 2003, Biotechnology and bioengineering.

[8]  K. Schügerl,et al.  Measuring, modelling, and control , 1991 .

[9]  Matti Leisola,et al.  Modeling and simulation of Streptomyces peucetius var. caesius N47 cultivation and ɛ-rhodomycinone production with kinetic equations and neural networks , 2006 .

[10]  Linda M. Harvey,et al.  Monitoring of Submerged Bioprocesses , 1999 .

[11]  Christopher L. Davey,et al.  The influence of electrode polarisation on dielectric spectra, with special reference to capacitive biomass measurements I. Quantifying the effects on electrode polarisation of factors likely to occur during fermentations , 1998 .

[12]  Arthur K. Kordon,et al.  Biomass Inferential Sensor Based on Ensemble of Models Generated by Genetic Programming , 2004, GECCO.