ORIGINAL RESEARCH
Bioflocculant Production by a Consortium
of Two Bacterial Species and Its Potential
Application in Industrial Wastewater
and River Water Treatment
Sekelwa Cosa, Anthony Okoh
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Applied and Environmental Microbiology Research Group (AEMREG),
Department of Biochemistry and Microbiology, University of Fort Hare,
Private Bag X1314, Alice 5700, South Africa
Pol. J. Environ. Stud. 2014;23(3):689-696
KEYWORDS
ABSTRACT
We assessed the bioflocculant production potentials of a consortium of two marine bacterial species
belonging to the Oceanobacillus and Halobacillus genera, isolated from sediment samples of Algoa Bay in
the Eastern Cape Province of South Africa. Cell free culture broth of the consortium had a flocculating activity
of 98.3%, which is higher than those of pure cultures of the individual species. The purified bioflocculant
was more efficient (optimum dose 0.2 mg·ml-1) in the flocculation of kaolin suspension (4 g·l-1) compared to
polyelectrolyte (optimum dose 0.3 mg·ml-1) and alum (optimum dose 1 mg·ml-1), which are both commercially
available coagulants. A neutral pH condition and the presence of Ca2+ as cation resulted in optimum
activity of the bioflocculant. Also, the purified bioflocculant removed chemical oxygen demand (COD) in
brewery wastewater, dairy wastewater, and river water at efficiencies of 99.7, 99.9, and 63.5%, respectively,
and also reduced their turbidity by 93.9, 88.3, and 98.6%, respectively. Composition analysis revealed the
bioflocculant to be mainly polysaccharide with an amorphous-crystal-like structure. FTIR spectra revealed
the presence of carboxyl, hydroxyl, and amino groups in its thermo-stability test, suggesting a thermostable
bioflocculant.