H. Senn et al., THE GROWTH OF ESCHERICHIA-COLI IN GLUCOSE-LIMITED CHEMOSTAT CULTURES - A REEXAMINATION OF THE KINETICS, Biochimica et biophysica acta (G). General subjects, 1201(3), 1994, pp. 424-436
The relationship between specific growth rate (CL) and steady-state gl
ucose concentration was investigated for Escherichia coli ML30 in carb
on-limited chemostat culture. This was made possible by the developmen
t of a method for measuring reducing sugars in culture media in the mu
g.l(-1)-range. Cells initially cultivated in batch culture at high gl
ucose concentrations required long-term adaptation to nutrient-limited
growth conditions in the chemostat (between 100-200 volume changes at
D = 0.6 h(-1)) until steady-state with respect to residual glucose co
ncentration was reached; for adapted cells, however, new steady-state
glucose concentrations were usually obtained within less than 10 volum
e changes. A statistical evaluation of different kinetic models showed
that between 0.2 h(-1) < D < 0.8 h(-1) the three models proposed by M
onod (1942), Shehata and Marr (1971), and Westerhoff et al. (1982) des
cribed the data equally well and the applicability of the different mo
dels is discussed. Depending on the model used, calculated glucose con
centrations supporting half maximum growth rate (K-s) Were in the rang
e of 40-88 mu g.l(-1). The data strongly suggest that the large differ
ences in K-s constants reported in the literature (ranging from 40 mu
g.l(-1) up to 99 mg.l(-1)) are due to the use of E. coli cells adapted
to different degrees to nutrient-limited growth conditions. This indi
cates that it is probably not possible to describe the kinetic propert
ies of a bacterium with a single set of kinetic 'constants'.