J. A. Roels

Description of microbial growth behaviour during the wash-out phase; determination of the maximum specific growth rate

SummaryMicrobial growth during the wash-out phase has been described by an unstructured model based on Monod kinetics and the relation of linear substrate consumption. The optimal experimentation range and procedure have been evaluated for accurate estimation of the maximum specific growth rates.

EFFECT OF WATER ACTIVITY ON MICROBIAL GROWTH

ABSTRACT The influence of water activity on the growth kinetics and energetics of Klebsiella pneumoniae was investigated in batch cultures. The effects of decreasing water activity on various yields, maximum specific growth rate and lag time were determined. Thermodynamic efficiency of the growth process was evaluated and correlated to the water activity in the medium. Results indicate that water activity is an important parameter influencing the kinetics and energetics of bacterial growth with far reaching implications for industrial biological processes.

Comments on the description of the maintenance metabolism during anaerobic growth with product formation

SummaryProduct formation during anaerobic growth in the absence of any other electron acceptor has been shown to be linked to the energy production processes. It has been demonstrated that when this fact is not taken into account, experimental data results in an incorrect description of the maintenance metabolism.

The bioenergetic correlation of COD to BOD

SummaryA simple expression has been derived to demonstrate that the ratio of COD to BOD is not constant but a function of the thermodynamic efficiency of the growth process. An analysis of data reported in literature indicates that this ratio can assume a wide range of values for different substrates. The influence of a selected change in the environmental conditions, on the ratio, COD/BOD, has been evaluated experimentally, in a bacterial system.