Gellan Gum Biosynthesis in Microorganisms: Current Status and Future Directions

Gellan gum is a widely used gel polysaccharide that is gaining market preference because of its unique gel characteristics. Although the biological synthesis of gellan gum dates back to the 1970s, research into its synthetic metabolic pathways has lagged behind that of other polysaccharides because of a lack of clarity. In recent years, driven by growing market demand and advancements in our understanding of metabolic pathways, as well as the rapid development of genetic engineering tools, the biological synthesis of gellan gum has progressed significantly. This article summarizes the developmental history of Sphingomonas paucimobilis ATCC 31461 and the structure of gellan gum, with a particular focus on the metabolic pathway involved in the production of gellan gum by these strains. This review discusses the metabolic engineering and research progress of key genes at different stages of the synthesis pathway. Additionally, this article introduces strategies for obtaining high-titer strains using traditional breeding methods and metabolic engineering approaches. Finally, it addresses the methods for producing low-molecular-weight-gellan gum. We discuss ongoing disputes in the field and highlight promising directions for future research. This review aims to address the bottlenecks in gellan gum production by promoting a greener and more sustainable manufacturing process.