Sludge settling and algal flocculating activity of extracellular polymeric substance (EPS) derived from bacillus cereus SK

Exopolysaccharides (EPS) of microbial origin is a promising alternative to chemical flocculants due to their sustainability and eco-friendly nature. In the present study, EPS produced by Bacillus cereus SK was studied and their flocculating activity was investigated. On incubation for 48 h, B. cereus SK produced 0.91960.022 g/L of EPS from a cell mass of 3.5960.06 g/L. The isolated EPS was identified as glycoprotein and chemical characterization by FTIR spectroscopic analysis suggested the presence of hydroxyl, amino and carboxyl groups. The kaolin clay flocculating activity of 83.4% was obtained on treatment with 12 mg/L of EPS. At 30% (v/v) of EPS 31.2264.71 mL/g of Sludge volume index (SVI) and 34.4461.51 mL/g of algal flocculation was observed. The EPS produced by B. cereus SK was non-toxic and did not exert any adverse effect on Danio rerio even at a concentration of 800 mg/mL.