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

Abstract

Abstract 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 0.919 ± 0.022 g/L of EPS from a cell mass of 3.59 ± 0.06 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 31.22 ± 4.71 mL/g of Sludge volume index (SVI) and 34.44 ± 1.51 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.