Metabolic flux analysis (MFA) is a critical technique for examining the production and consumption rates of metabolites in biological systems. In systems metabolic engineering, MFA helps understand cell physiology under specific conditions and predict metabolic capacities of cells following genetic or environmental changes. MFA is also used to elucidate cellular mechanisms. By using stable isotope labeling (such as 2H, 13C, and 15N), MFA can track isotopic labels along metabolic pathways, thereby identifyin