Optimization of culture conditions for the production of exopolysaccharides from marine isolate Citrobacter sp.

Abstract

Exopolysaccharide (EPS) samples were collected from the Mandapam camp, India. Morphological, biochemical characterization and 16S rRNA gene sequencing were done and the candidate bacterium was confirmed as Citrobacter sp. EPS production was observed from bacteria in Malt medium broth (0.88 ± 0.04mg/ml). The optimal cultural conditions for EPS production were as follows: after 72 hours of incubation at pH 8.0 (0.75 ± 0.1 mg/ml), the temperature at 40⁰C (0.75 ± 0.1 mg/ml), 100 rpm (0.90 ± 0.1 mg/ml). In the experimentation, arabinose (carbon sources) (1. ± 0.120 mg/ml) and ammonium nitrate (nitrogen) (1.30 ± 0.1 mg/ml) showed better results for the yield of EPS. The highest production of EPS was recorded in Triton X-100 (surfactants) supplemented medium. The optimal production of EPS was obtained in 2.5% sodium chloride added medium. Then the 2.5% inoculum concentration better for maximizing the yield of EPS. The best yield of EPS was noticed in after 96 hours of incubation time.