Screening and optimisation of crude exopolysaccharide production by marine Brevibacterium sp. JAB08 isolated from the jellyfish Chrysaora sp. from the coastal waters of Goa.

Marine jellyfish harbor diverse bacterial communities with potential biotechnological relevance. In this study, eleven bacterial isolates were obtained from different body parts (oral arms, gastric cavity, and mucus) of the jellyfish Chrysaora sp. collected from the coastal waters of Goa, India, and screened for exopolysaccharide (EPS) production. Among the screened isolates, Brevibacterium sp. JAB08 demonstrated the highest crude EPS production potential. Optimisation using a Box-Behnken Design coupled with response surface methodology identified sucrose 3% (w/v), inoculum size 2% (v/v), and an incubation period of 36 h as the optimal fermentation conditions with EPS yield of 4.26 g l-1 in shake flask. Notably, this yield was achieved in 36 h, compared to 96 h required to reach a comparable yield under unoptimised conditions, indicating improved process efficiency, structural characterisation by FTIR revealed a neutral polysaccharide dominated by β-glycosidic linkages, while SEM revealed a porous, three-dimensional network of spheroidal aggregates. Overall, the results of the present study position jellyfish-associated microbes as a promising and largely unexplored source of exopolysaccharides with potential implications for sustainable marine biopolymer production following purification and compositional analysis.