A novel bioflocculant produced by Enterobacter aerogenes and its use in defecating the trona suspension

In this paper, a bioflocculant-producing bacterium, named W-23, was isolated from soil and identified as Enterobacter aerogenes. The bioflocculant (named WF-1) produced by W-23 was an acidic polysaccharide composed mainly of uronic acid (13.2%), pyruvic acid (7.4%) and acetic acid (1.6%). The three components sugars of WF-1 were glucose, fructose and manose, and the molar ratio was 10.3:5.4:1 for glucose:fructose:manose. The influence of factors like temperature, bioflocculant dosage and concentration of positive ions on the flocculation were studied. The optimal conditions were as follows: temperature 45 °C, WF-1 90 mg/L and Zn2+ 0.03 mol/L. As a result, the sedimentation rate was 2.96 × 10−4 m/s, and the OD of supernatant reached 0.05. The efficiency of the bioflocculant was better than that of conventional chemically synthesized flocculants, such as anionic polyacrylamide or non-ionic polyacrylamide.