What is metabolic flux analysis and how is it used in bioprocess development?

Metabolic flux analysis (MFA) quantifies intracellular reaction rates, providing insight into cellular metabolism beyond what extracellular measurements reveal. Approaches include: stoichiometric MFA (using mass balances and measured uptake/secretion rates), 13C-MFA (tracing isotope-labeled substrates through pathways), and flux balance analysis (FBA, constraint-based modeling). Applications in bioprocess development include: identifying metabolic bottlenecks limiting product synthesis, comparing high and low producers to guide strain improvement, optimizing media and feeding strategies, understanding metabolic shifts during cultivation, and rational design of metabolic engineering targets. Integration with -omics data and kinetic models enhances predictive power.