Antonie van Leeuwenhoek

, Volume 63, Issue 3, pp 289–298

Kinetics of microbial growth with mixtures of carbon sources

Authors

  • Thomas Egli
    • Swiss Federal Institute for Environmental Science and Technology (EAWAG) and Swiss Federal Institute of Technology (ETH)
  • Urs Lendenmann
    • Swiss Federal Institute for Environmental Science and Technology (EAWAG) and Swiss Federal Institute of Technology (ETH)
  • Mario Snozzi
    • Swiss Federal Institute for Environmental Science and Technology (EAWAG) and Swiss Federal Institute of Technology (ETH)
A Glimpse Towards Nature

DOI: 10.1007/BF00871224

Cite this article as:
Egli, T., Lendenmann, U. & Snozzi, M. Antonie van Leeuwenhoek (1993) 63: 289. doi:10.1007/BF00871224

Abstract

Several investigations have shown that during growth in carbon-limited chemostats the simultaneous utilisation of carbon substrates which usually provoke diauxie under batch conditions, i.e., ‘mixed substrate growth’, is probably the rule under ecologically relevant growth conditions. In contrast, the models presently available for the description of the kinetics of microbial growth are all based on the use of single substrates. Systematic studies in chemostat culture have shown that steady-state residual concentrations of individual compounds were consistently lower during mixed substrate growth than during growth with the single substrates. This effect is clearly demonstrated for the case ofEscherichia coli growing with mixtures of glucose plus galactose. The data presented indicate that the extent of reduction of steady-state residual substrate concentration is dependent on the proportions of the substrates in the mixture, the nature of substrates mixed and the regulation pattern of enzymes involved in their breakdown. If this behaviour can be shown to be typical for growth under environmental conditions, it may provide an explanation why microbes still grow relatively fast at the low substrate concentrations encountered in nature.

Key words

carbon limitationchemostatEscherichia coligalactoseglucosegrowth kineticsmixed substratesresidual substrate concentration

Abbreviations

S0

Substrate concentration in medium fed to chemostat (mg L−1)

D

Dilution rate (h−1)

DW

Biomass dry weight (mg L−1)

μ

Specific growth rate μmax, maximum specific growth rate (h−1)

Ks

Monod affinity constant for substrate s, K1,2, for substrates 1, 2, respectively (mg L−1, µg L−1)

qA

Specific consumption rate for substrate A, qtotal, total specific substrate consumption rate (mg A [mg DW]−1 h−1)

s

Concentration of substrate in culture, sA, of substrate A (mg L−1, µg L−1)

sA

Steady-state concentration of substrate A in chemostat,sA(100%), during growth with A only,sA(mix), during growth with mixture (mg L−1, µg L−1)

YX/S

Growth yield from substrate S (g dry biomass [g substrate]−1)

Copyright information

© Kluwer Academic Publishers 1993