Background:
Osmolyteswith their effective stabilizing properties are accumulated as protectants not only against
salinity but also against denaturing harsh environmental stresses such as freezing, drying, high temperatures,
oxygen radicals and radiation. The present work seeks to understand how
Halomonas
sp. AAD12 cells redirect
carbon flux specifically to replenish reactions for biomass and osmolyte synthesis under changing salinity and
temperature. To accomplish this goal, a combined FBA–PCA approach has been utilized.
Results:
Experimental data were collected to supply model constraints for FBA and for the verification of the
model predictions, which were satisfactory. With restrictions on the various combinations of selected
anaplerotic paths (reactions catalyzed by phosphoenolpyruvate carboxylase, pyruvate carboxylase or
glyoxylate shunt), two major phenotypes were found. Moreover, under high salt concentrations, when the
glucose uptake rate was over 1.1 mmoL DCW
-1 h
-1, an overflow metabolism that led to the synthesis of
ethanol caused a slight change in both phenotypes.
Conclusions:
The operation of the glyoxylate shunt as the major anaplerotic pathway and the degradation of
6-phosphogluconate through the Entner–Doudoroff Pathway were the major factors in causing a distinction
between the observed phenotypes.
