Comprehensive evaluation of the multifaceted bioactivities of exopolysaccharides derived from marine bacteria Halomonas sp. DU-15-9-1 and Salinicoccus roseus S-5-9-3

Abstract

The increasing demand for biodegradable, sustainable, and multifunctional biopolymers has intensified research on microbial exopolysaccharides (EPSs), particularly from extremophilic microorganisms. However, the bioactive potential of EPSs derived from halophilic bacteria remains underexplored. Therefore, the present study aimed to investigate. Exopolysaccharides (EPSs) are high molecular weight biopolymers composed predominantly of sugar monomers, exhibiting diverse chemical structures and properties. The structural diversity of EPSs from halophilic bacteria underpins their utility in environmental remediation and cosmetic formulations, owing to their physicochemical stability and functional properties. In a comprehensive study, two bacterial isolates, Halomonas sp. DU-15-9-1 and Salinicoccus roseus S-5-9-3 were examined for their capacity to synthesize EPSs with bioactive potential. The extraction and purification of EPSs from these isolates revealed significant functional activities. The EPS derived from both Halomonas sp. DU-15-9-1 (52.45%) and S. roseus S-5-9-3 (55.45%) demonstrated an emulsifying activity with coconut oil and groundnut oil, respectively, suggesting their potential as an emulsifying agent. Additionally, the antioxidant assays exhibited 52.68% and 64.82% radical scavenging activity, suggesting their usage as natural antioxidants. While the flocculating activity, a noteworthy feature for particulate aggregation in environmental processes, was 93% and 92%, respectively. The IC₅₀ values against HeLa cells of 104.10 ± 9.26 µg/mL and 96.05 ± 5.54 µg/mL and against MCF-7 breast cancer cells 31.09 ± 0.63 µg/mL and 24.19 ± 0.22 µg/mL EPSs, respectively, demonstrate their cytotoxic effect and potential use as an anticancer agent. Thus, the multifaceted applications of microbial EPSs will certainly pave the way for futuristic research and biotechnological applications in the areas of food, cosmetics, environmental management, and pharmaceuticals.