Microbial biosynthesis of fruit-like aroma compounds: Strategies and challenges toward sustainable food flavor production.

Fruit-like aroma compounds play a crucial role in the sensory quality of food and are commonly utilized as natural flavoring agents. However, the extraction from plants faces challenges such as seasonal variability, low yields, and environmental impacts. Microbial biosynthesis offers a scalable and sustainable alternative. Therefore, this review focuses on, major compound classes and their biosynthetic routes, followed by recent progress in microbial production. Engineering advances are organized into five coordinated strategies: chassis optimization, heterologous pathway reconstruction, catalytic protein engineering, metabolic/cofactor redistribution, and fermentation process control. Emerging tools, including dynamic regulation, spatial enzyme co-localization, and machine learning assisted design, are surveyed for their impact on titer, selectivity, and aroma complexity. Special attention is given to consolidating compound classes, host chassis, key pathway modules, and reported titers and operating conditions, providing a comparative map of state-of-the-art performance and exposing gaps for future optimization. An in-depth examination of ongoing issues, such as enzyme versatility, product toxicity, and scalability limitations, provides actionable recommendations for developing effective, resilient, and sustainable microbial systems for the food, beverage, and fragrance sectors.