Reduced temperature sensitivity of immobilized Nitrobacter agilis cells caused by diffusion limitation

• Published in: Enzyme and microbial technology Vol. 20; no. 8; pp. 573 - 580
• Main Authors: Leenen, E.J.T.M., van Boxtel, A.M.G.A., Englund, G., Tramper, J., Wijffels, R.H.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01-06-1997; Elsevier Science
• Subjects: Biological and medical sciences; Biotechnology; dynamic modelling; Fundamental and applied biological sciences. Psychology; immobilized cells; low temperatures; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Nitrification; Nitrobacter agilis; Sectie Proceskunde; Sub-department of Food and Bioprocess Engineering; temperature sensitivity analysis; dynamic modelling; low temperatures; temperature sensitivity analysis; immobilized cells; Nitrification; Nitrobacter agilis; Airlift reactor; Bioreactor; Sensitivity; Nitrobacteraceae; Medium effect; Microorganism culture; Bacteria; Dynamic model; Nitrobacter winogradskyi; Entrapped microorganism; Low temperature
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/S0141-0229(96)00214-1

A dynamic model describing substrate consumption and growth of immobilized biomass was extended to predict and study the effect of variations in temperature. This was done by including temperature relations for all the individual parameters that are influenced by temperature.
A sensitivity analysis was executed to identify the parameters that determine the temperature sensitivity of the overall process in the different cultivation phases. The model was evaluated by cultivating immobilized
Nitrobacter agilis cells in an airlift loop reactor at various temperatures between 6–30°C. The dynamics of the system were studied by imposing temperature changes during the cultivation. The model describes the effect of low temperatures on the macroscopic consumption rate fairly well. As predicted, immobilized cells are less sensitive to temperature changes than suspended cells. The macroscopic consumption rate of immobilized
N. agilis cells at 10°C is around 70% of the macroscopic consumption rate at 30°C while in the case of suspended cells, this consumption rate is only 15%.