This review article provides a comprehensive overview of yeast cell wall mannan, focusing on its structural features, biological activities, and production strategies. Yeast cell walls consist of β-1,3-glucan, chitin, and mannan, with mannan being the outer layer responsible for 30-50% of the cell wall mass. Mannan exhibits various biological activities, including gut health promotion, immune regulation, antioxidant properties, and reduced hyperlipidemia. The review discusses the extraction methods for mannan, such as alkaline, acid, and enzymatic processes, and highlights the importance of optimizing conditions for yield and purity. Additionally, it explores strategies for enhancing mannan production through yeast strain engineering, including random and directed mutations, rational engineering of the biosynthetic pathway, and heterologous mannan production. The article concludes by emphasizing the potential of yeast cell wall mannan in functional foods, nutraceuticals, and industrial applications.This review article provides a comprehensive overview of yeast cell wall mannan, focusing on its structural features, biological activities, and production strategies. Yeast cell walls consist of β-1,3-glucan, chitin, and mannan, with mannan being the outer layer responsible for 30-50% of the cell wall mass. Mannan exhibits various biological activities, including gut health promotion, immune regulation, antioxidant properties, and reduced hyperlipidemia. The review discusses the extraction methods for mannan, such as alkaline, acid, and enzymatic processes, and highlights the importance of optimizing conditions for yield and purity. Additionally, it explores strategies for enhancing mannan production through yeast strain engineering, including random and directed mutations, rational engineering of the biosynthetic pathway, and heterologous mannan production. The article concludes by emphasizing the potential of yeast cell wall mannan in functional foods, nutraceuticals, and industrial applications.