Premium
Co‐immobilized Nitrosomonas europaea and Nitrobacter agilis cells: validation of a dynamic model for simultaneous substrate conversion and growth in κ‐carrageenan gel beads
Author(s) -
Hunik Jan H.,
Bos Cees G.,
van den Hoogen Marijke P.,
De Gooijer Cornelius D.,
Tramper Johannes
Publication year - 1994
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260431121
Subject(s) - nitrosomonas europaea , nitrobacter , substrate (aquarium) , carrageenan , nitrosomonas , chemistry , chromatography , chemical engineering , nitrification , biochemistry , biology , ecology , organic chemistry , nitrogen , engineering
Abstract A dynamic model for two microbial species immobilized in a gel matrix is presented and validated with experiments. The model characterizes the nitrification of ammonia with Nitrosomonas europaea and Nitrobacter agilis co‐immobilized in K ‐carrageenan gel beads. The model consists of kinetic equations for the microorganisms and mass transfer equations for the substrates and products inside and outside the gel beads. The model predicts reactor bulk concentrations together with the substrate consumption rate, product formation, and biomass growth inside the gel beads as a function of time. A 50–day experiment with immobilized cells in a 3.3‐dm 3 air‐lift loop reactor was carried out to validate the model. The parameter values for the model were obtained from literature and separate experiments. The experimentally determined reactor bulk concentrations and the biomass distribution of the two microorganisms in the gel beads were well predicted by the model. A sensitivity analysis of the model for the given initial values indicated the most relevant parameters to be the maximum specific growth rate of the microorganisms, the diffusion coefficient of oxygen, and the radius of the beads. The dynamic model provides a useful tool for further study and possible control of the nitrification process. © 1994 John Wiley & Sons, Inc.