Metabolic Flux Analysis and 13C Metabolic Flux Analysis

Providing a comprehensive understanding of cell metabolism

Genome-scale metabolic models (GEMs) are comprehensive representations of metabolic networks reconstructed from genome annotation and literature, and can be used to predict metabolic fluxes. Used in this manner, GEMs can be used to identify genetic targets to be deleted, down-regulated or over-expressed for improving the production of target products in host strains.

For example, OptForce identifies potential gene targets by classifying metabolic reactions with regard to necessary changes in flux (i.e., increase, decrease, or zero) to meet a pre-specified overproduction target. The efficiency and quality of engineering interventions predicted by such strain design methods depend on the availability of flux measurement or multi-omics data for host strains. 

13C Metabolic Flux Analysis (MFA) is the gold standard for measuring intracellular metabolic fluxes. 13C MFA is based on the use of 13C labeling experiments, in which labeled carbon sources are fed to the organism under study. The ensuing metabolite labeling is combined with experimentally measured extracellular fluxes to provide a “radiography” of internal metabolic fluxes.

If coupled with GEMs, this method can provide a rigorous and comprehensive understanding of cell metabolism. The knowledge of these internal metabolic fluxes is valuable for understanding bottlenecks and side reactions to maximize efficiency of carbon utilization and maximizing titer, rate and yield in the conversion of substrates to target products in host strains.

  • Pacific Northwest National Laboratory
  • Lawrence Berkeley National Laboratory
  • National Renewable Energy Laboratory