(451ab) Design of Isotope Labeling Experiments for Metabolic Flux Analysis in Escherichia Coli under Anaerobic Condition

In recent years, metabolic flux analysis (MFA) has become an important
tool in metabolic engineering. The MFA involves the quantification of
intracellular metabolic fluxes in a microorganism. The result of MFA is a
metabolic flux map that allows the systematic study of cellular responses to
genetic and environmental perturbations. Carbon isotope labeling-based MFA,
with analysis by NMR or GC/MS, has gained wide use in the metabolic engineering
community for estimating metabolic fluxes in central carbon metabolism.

However, the ¹³C labeling based MFA has been used for aerobic
system and has not done been for anaerobic system. The ¹³C MFA is
challenging under anaerobic condition as there is not less rearrangement
because TCA cycle is not complete. The information from the labeled substrate
can be increased through the proper choice of labeled substrate. We have come
up with the optimal choice of labeled substrate for the experimental condition
by flux identifiability analysis. The metabolic network model for MFA has been
constructed for E. coli and it consists of all principal pathway
of primary metabolism (PTS transport of glucose, glycolysis, pentose phosphate
pathway, TCA cycle, glyoxylateshunt, and fermentative reactions)
and the biosynthetic pathways that convert  the primary
metabolic precursors to sink metabolites.