Characterization and flocculation mechanism of an alkali-activated polysaccharide flocculant from Arthrobacter sp. B4

• DOI: 10.1016/j.biortech.2014.07.112
• Publication Date: 2014-08-12T17:15:58Z
• Authors: Yumei Li; Qiang Li; Dakui Hao; Zhiheng Hu; Dongxue Song; Min Yang
• Keywords: Spectrophotometry; Polysaccharides, Bacterial; Flocculation; Alkalies; Arthrobacter; Hydrogen-Ion Concentration; 01 natural sciences; 6. Clean water; Water Purification; 0105 earth and related environmental sciences

The characterization and flocculation mechanism of a bioflocculant produced by Arthrobacter sp. B4 were investigated. The bioflocculant's active ingredient was a polysaccharide (B4-PS) that consisted of three main fractions corresponding to the molecular weights of approximately 3.97×10(4)Da, 6.84×10(3)Da and 5.9×10(6)Da, respectively. These fractions were composed of galactose, glucose, mannose and glucuronic acid. Flocculation experiments showed that B4-PS could spontaneously flocculate in the presence of Ca(2+) ions at a high pH (>12.0), followed by the pH reduction to ∼6.0. The self-flocculation of B4-PS may be mediated by ionization and charge neutralization mechanism. Furthermore, B4-PS exhibited excellent capabilities for pollutant removal and pH reduction in alkaline wastewater. These data suggest B4-PS may be a promising tool for use in industrial alkaline wastewater pretreatment.