Recent advances in microbial production of stress-relieving nutraceuticals.

The fast-paced modern life exerts great pressure to individuals. Nutritional interventions for stress management have gained increasing attention due to its favorable safety profiles, multiple health benefits, and suitability for vulnerable populations. Microbial production of stress-relieving nutraceuticals represents a sustainable alternative to natural extraction and chemical synthesis, while meeting the growing market demand for natural-labeled and consumer-preferred products. This review provides an overview of the recent progress in engineering microorganisms to produce common stress-relieving biomolecules, such as: γ-aminobutyric acid, ʟ-theanine, 5-hydroxytryptophan and its derivatives, and vitamin B. Key bottlenecks limiting the bioproduction of each molecules and targeted strategies, including chassis selection, enzyme engineering, pathway rewiring and bioprocess regulation, are discussed.