0000000000328682
AUTHOR
Talal Belguendouz
showing 3 related works from this author
pH Homeostasis and Citric Acid Utilization: Differences Between Leuconostoc mesenteroides and Lactococcus lactis
1997
This study presents the effects of citric acid and extracellular pH (pHe) on the intracellular pH (pHi) of wild-type and citrate negative variants (cit−) Leuconostoc mesenteroides subsp. mesenteroides (Ln. mesenteroides M) and Lactococcus lactis subsp. lactis bv. diacetylactis (L. lactis LD). A recent method using a pH-sensitive fluorescent indicator carboxyfluorescein succinimidyl ester (cFSE) was adapted to measure the pHi of these two lactic acid bacteria in resting cells. Energized cells with 10 mM lactose of Ln. mesenteroides M and L. lactis LD modified their pH gradient (ΔpH) in the same manner; when the pHe was decreased from 7 to 4, the pHi decreased from 7 to about 5. The adjunctio…
Kinetics of citrate uptake in growing cells ofLeuconostocspp.
1996
Citrate uptake was studied in growing cells of Leuconostoc mesenteroides subsp. mesenteroides. A Michaelis-Menten pattern with the dianionic form of citrate as the limiting substrate has been proposed. It was validated for different fermentations varying the initial citrate concentrations and the pH medium. This latter did not modify the rate of the process which was clearly confirmed using experiments with resting cells. The model was used to compare the kinetics of citrate consumption between several strains of Leuconostoc mesenteroides subsp. mesenteroides, Leuconostoc mesenteroides subsp. cremoris and Leuconostoc lactis.
Influence of lactose-citrate co-metabolism on the differences of growth and energetics in Leuconostoc lactis, Leuconostoc mesenteroides ssp. mesenter…
1999
International audience; The biodiversity of growth and energetics in Leuconostoc sp. has been studied in MRS lactose medium with and without citrate. On lactose alone, Ln. lactis has a growth rate double that of Ln. cremoris and Ln. mesenteroides. The pH is a more critical parameter for Ln. mesenteroides than for Ln. lactis or Ln. cremoris; without pH control Ln. mesenteroides is unable to acidify the medium under pH 4.5, while with pH control and as a consequence of a high Y(ATP) its growth is greater than Ln. lactis and Ln. cremoris. In general, lactose-citrate co-metabolism increases the growth rate, the biomass synthesis, the lactose utilisation ratio, and the production of lactate and …