Cosa S, Ugbenyen AM, Mabinya L, Karl Rumbold and Okoh AI.(2013) Characterization andflocculationefficiency of a bioflocculant produced by a marine bacteria belonging to theHalobacillus genus. EnvironmentalTechnology. 34(18): 2671-2679 (Taylor & Francis).

Abstract: We reported earlier on the bioflocculant production potential of Halobacillussp. Mvuyo, a marine bacteria isolated from Algoa Bay sediment samples. In this paper we report on the detailed characterization of the purified bioflocculant composed of polysaccharide and protein. The optimum dose of the purified bioflocculant for the clarification of 4 g l?1 kaolin clay suspension was 0.2 mg ml?1 at neutral pH. Scanning electron micrograph (SEM) revealed the bioflocculant to have an amorphous structure. The Fourier transform infrared (FTIR) spectrum exhibited the presence of hydroxyl, carboxyl and amino groups in its structure. The bioflocculant was thermostable with relative bioflocculant activity residue of 74.4% after heat treatment at 100?C. Moreover thermogravimetric analysis (TGA) exhibited a degradation temperature (Td) of ? 140?C. The flocculationefficiency of the bioflocculant was 86.2% compared with 82.6%, 74.5% and 70.9% for polyethylimine, ferric chloride andalum, respectively. This bioflocculant has immense promise as a substitute to inorganic and synthetic flocculants in view oftheir hazard implications.

Keywords: Halobacillussp; bioflocculant; flocculation activity; glycoprotein; characterization