Keywords: microbial growth, antigen production, metabolic irreversibility, microbial heat generation, metabolic exergy destruction, entropy generation, thermodynamic analysis, Neisseria meningitidis, kinetic modelling, biomass production, exergetic efficiency, stress conditions
Thermodynamic analysis of serogroup C antigen production by Neisseria meningitidis
Kinetic and thermodynamic models are developed to relate substrate consumption, serogroup C antigen production and growth rate of Neisseria meningitidis, a meningitides causing bacterium during the uncontrolled, pH controlled and dissolved oxygen controlled cultivation. The model shows that the microorganisms used their energy metabolism the most efficiently in the case of the guaranteed presence of the dissolved oxygen, e.g., the ultimate acceptor of the electrons in the electron transport chain. The largest heat loss per unit biomass production, the largest exergy loss per unit biomass production, and the largest entropy generation per unit biomass production are accounted in the pH controlled experiment, indicating that the growth is achieved under thermodynamically unfavourable conditions. The exergetic efficiency of the microbial production and the antigen production are not parallel, confirming the discussion accounted in the literature that the antigen is produced best under the stress conditions.