What strategies are used for metabolic engineering of production strains?

Metabolic engineering strategies include: overexpression of rate-limiting enzymes (identify through flux analysis), deletion of competing pathways (redirect carbon toward product), cofactor engineering (balance NADH/NADPH supply/demand), precursor supply optimization (enhance availability of building blocks), transporter engineering (improve substrate uptake or product export), and dynamic regulation (biosensors controlling expression based on metabolite levels). Analysis tools: metabolic flux analysis (13C labeling), genome-scale metabolic models (constraint-based modeling), and adaptive laboratory evolution for complex phenotypes. Modern approaches: CRISPR-based multiplex editing, modular pathway engineering, and machine learning-guided optimization. Considerations include genetic stability, metabolic burden, and industrial robustness. Success examples include artemisinin, 1,3-propanediol, and amino acid production.