Microbial dextran production: biosynthetic mechanism, fermentation strategies, and downstream processing

Dextran is a microbial homopolymer of α-glucan, consisting of α-(1,6) glycosidic linkage backbone with side chains branching via α-(1,2), α-(1,3), or α-(1,4) linkages. Due to its distinctive characteristics, including molecular mass, compatibility, and thermal stability, it is widely applied in various fields, such as food, pharmaceutical, biomedical, and environmental applications. Although previous reports have illustrated the application of microbial sources and the essential factors influencing fermentation and enzymatic pathways, a sustainable strategy for bioprocess engineering to produce microbial dextran has not been elaborated upon. This review provides a systematic and comprehensive overview of microbial dextran production, aiming to enable green bioprocess engineering strategies that enhance production for industrial applicability, promoting a sustainable approach.