Abstract: Selenium is an essential trace element for the human body. Dietary selenium intake among Chinese residents is generally insufficient, and the problem of “selenium-related hidden hunger” is becoming increasingly prominent. Selenoproteins are a class of proteins with selenocysteine (Sec) as their active centers; they possess unique redox properties and demonstrate significant application potential in the functional food sector. However, their large-scale production is constrained by technical bottlenecks such as the complex Sec insertion mechanism and low heterologous expression efficiency. Microalgae, as a vital biological resource under the “Greater Food Approach”, offer advantages including rapid growth rates, high nutritional value, and the potential for large-scale cultivation, thereby being an ideal host for constructing selenoprotein cell factories. This paper systematically reviews the biosynthesis and metabolic regulation mechanisms of selenoproteins derived from microalgae and compares the similarities and differences in Sec insertion mechanisms among various host organisms. Meanwhile, it explores the mechanisms by which microalgal selenoproteins improve food flavor and summarizes their future application prospects in the food sector. Finally, this paper discusses feasible pathways for constructing highly efficient microalgal selenoprotein cell factories based on synthetic biology strategies, with the aim of providing a reference for the development of functional foods.

Key words: selenoproteins; microalgae; selenocysteine; cell factories; future food