From Microbial Fermentation to Functional Biomaterials: An Integrative Review of Bacterial Exopolysaccharide Detection, Production, Purification, Characterization, and Emerging Applications

Bacterial exopolysaccharides (EPSs) are high-molecular-weight carbohydrate polymers secreted outside the cell wall, and they have attracted sustained interest across both basic science and industrial research. Their structural diversity — shaped by differences in monomer composition, glycosidic linkage patterns, branching frequency, and non-sugar substituents — translates directly into a wide range of physical and biological properties. This chemical versatility has made EPSs relevant to fields as different as food technology, biomedical engineering, pharmaceutical development, and environmental remediation. Lactic acid bacteria (LAB) remain among the most studied EPS producers, largely because of their long history of safe use in fermented foods. At the same time, commercially dominant polymers such as xanthan, bacterial cellulose, and levan produced by non-LAB species continue to define global market expectations for what biopolymers can deliver. Despite a growing volume of published research on these materials, the field has lacked a single reference that integrates all stages of EPS work into a coherent methodological account. This review fills that gap by examining, in sequence, the strategies used for strain detection and screening, approaches to improving fermentation yields, extraction and purification workflows, and the analytical methods used for structural and functional characterization. The review closes with a discussion of current limitations and the directions most likely to move the field forward, including the exploration of extremophilic bacteria, cell-free synthesis platforms, and the use of agricultural by-products as low-cost fermentation feedstocks.