Characterization of an extracellular polysaccharide produced by Bacillus sp.RL-2

1 Introduction a Bioflocculation is a dynamic process resulting fromsynthesis of extracellular polymer by living cells.Flocculant are widely used in industrial processesincluding wastewater treatment, downstream pro-cessing, and food and fermentation processes 1-6].The flocculants used can be classified into three groups1) inorganic flocculants such as aluminum sulfate andpoly-aluminum chloride; 2) synthetic organic high-polymer flocculants such as polyacrylamide derivativesand polyethylene i…

Characterization of an extracellular polysaccharide produced by Bacillus sp.RL-2

A strain secreting a strongly acidic polysaccharide flocculating agent was isolated from activated sludge, and identified as Bacillus brevis. The bioflocculant was produced by RL-2 during the late logarithmic growth in the batch culture and was recovered from supernatant by ethanol precipitation. The bioflocculant is thermo-stable as its activity remains stable after heated at 100℃ for 45 min. Its flocculating activity with kaolin suspensions was stimulated by the addition of Ca2 , Al3 and Cu2 . The flocculant consists of glucose, mannose, and galacturonic acid. Its average molecular mass was estimated to be approximately 2.86×105 by the method of viscosity. The flocculant aggregates various inorganic and organic compounds in solution.