Screening and characterization of bioflocculant isolated from thermotolerant Bacillus sp. ISTVK1 and its application in wastewater treatment
Asmita Gupta, Madan Kumar, Radha Mohan Sharma, Ritu Tripathi, Vivek Kumar, Indu Shekhar Thakur
Abstract
Bioflocculants are extracellular polymeric substances (EPS) that are produced by several microorganisms including bacteria. They find application in wastewater treatment wherein they are employed as flocculating agents for removal of suspended particles during the secondary clarification process. In this study, EPS produced by a previously studied thermotolerant strain Bacillus sp. ISTVK1 was analyzed for its flocculation property. The bacteria was cultured in basal and mineral media and the EPS extracted from the two types of cultures were analyzed for their structure, composition, and flocculation efficiency (%), which was tested on kaolin in terms of parameters like duration, pH, temperature and salts. Both types of EPS showed highest flocculating activity on 6th day, at pH 6, and temperature 32.7 °C and with salt AlCl 3 . When tested on real wastewater, physico-chemical analysis showed reduction in organics in samples treated with EPS and EPS+AlCl 3 . Aromatic contaminants like Diisobutyl benzene-1,2-dicarboxylate (Retention Time (R.T.) 22.55) and 2-Phenyl-n,n-bis(1-phenylethyl)-1,1-cyclobutanedicarboxamid (R.T. 44.21) were not detected in the bioflocculant treated samples. The study highlighted the applicability of bacterial EPS as a cost-effective bioflocculant for real wastewater.