Characterization and in vitro biological activities of exopolysaccharides from sugarcane waste-derived Weissella paramesenteroides.
Exopolysaccharides (EPS) are microbial biopolymers composed primarily of complex carbohydrates and are valued for their biocompatibility, biodegradability, and diverse biological activities. In this study, lactic acid bacteria were isolated from sugarcane waste, and a potent EPS-producing strain was identified as Weissella paramesenteroides through 16S rRNA gene sequencing. The sequence was deposited in GenBank under accession number PV786832. EPS production was optimized using a One-Factor-At-a-Time (OFAT) approach. Maximum EPS yield was obtained at pH 7, 30 °C, and 48 h incubation, with sucrose and yeast extract serving as the most effective carbon and nitrogen sources, respectively. Chemical analysis revealed a total carbohydrate content of 90% and a residual protein content of 3.7%. Structural characterization confirmed the presence of characteristic polysaccharide functional groups in the EPS. The EPS exhibited antibacterial activity against both Gram-positive and Gram-negative pathogens and demonstrated antioxidant properties, with a DPPH IC50 value of 188.6 µg/mL, ferric reducing antioxidant activity of 51.47 µg Trolox equivalents, and total antioxidant capacity of 160.02 ± 2.91 µg AAE/mL extract. Furthermore, the EPS showed dose-dependent anti-inflammatory activity with an IC50 value of 403.9 µg/mL. These findings highlight the bioactive potential of EPS from W. paramesenteroides and support its further exploration for biotechnological applications.