High-yield microbial synthesis of ectoine: advances in metabolic engineering, fermentation strategies, and food application prospects.
Ectoine, a cyclic amino acid derivative synthesized via the aspartate pathway, has emerged as a promising bioactive compound in the functional food industry owing to its exceptional protective effects on cellular structures and macromolecules. Despite its natural synthesis by halophilic microorganisms such as Halomonas, large-scale industrialization remains constrained by suboptimal yields and the technical complexities of hypersaline fermentation. To address these challenges, this structured narrative review outlines recent breakthroughs in the efficient biomanufacturing of ectoine. This review first outlines its biochemical properties and native biosynthetic mechanisms, followed by a comprehensive analysis of metabolic engineering strategies employed in both wild-type halophiles and engineered industrial chassis. At the molecular level, emphasis is placed on the precise regulation of the ectABC gene cluster, precursor pool expansion, and dynamic flux regulation to bypass feedback inhibition. At the process level, this article evaluates the impact of diverse fermentation optimization approaches-such as osmotic titration and sustainable feedstock utilization-and reviews advanced downstream separation and purification techniques. Finally, to overcome existing barriers to large-scale bio-manufacturing, this review prospects several critical future directions: the AI-driven intelligent design of microbial strains, dynamic metabolic regulation via biosensors, the development of novel microbial chassis and unconventional carbon sources, the digital and intelligent control of fermentation processes, and the advancement of continuous integrated downstream processing. Addressing these technological frontiers, alongside navigating food safety regulations, will facilitate the transition of ectoine toward efficient, green, and sustainable industrial production.