Bacillus circulans exopolysaccharide: Production, characterization and bioactivities

•EPS producing bacteria was isolated and identified as Bacillus circulans.•Media optimization by Response Surface Methodology using Box Behnken design.•Glucose, mannose, fructose and verbascose were identified as components.•B. circulans EPS exhibited appreciable antioxidant, anti-inflammatory and antitumor activity.

A bacterium with the ability to produce appreciable amount of exopolysaccharide was isolated from slimy layer of coconut. 16S rDNA analysis identified the organism as Bacillus circulans. EPS production was observed at all stages of culture growth and reached maximum of 0.065 mg/ml by 96 h, which on further incubation started to decrease. Response Surface Methodology using Box Behnken design has shown the influence of sucrose which was found to be directly proportional to exopolysaccharide production with production reaching 1.09 mg/ml. HPLC analysis identified the presence of glucose, mannose, fructose and verbascose and NMR analysis confirmed the presence of glucose, mannose and galactose. Even though the extracted B. circulans EPS did not show appreciable anti-bacterial or anti-fungal activity, it exhibited appreciable antioxidant, anti-inflammatory and anti-tumor activity.