| B-9 was collected from soil sample of Zhejiang University Huajiachi Campus. Some poly-macromolecule was synthesized from it, which showed the highest flocculating activity. The flocculating activity of B-9 was investigated during the culture process.The influence of carbon source, nitrogen source, C/N ratio on the bioflocculant production and the effect of pH, metal ion and CaCl2 concentration on the flocculating activity of B-9 had been studied in detail in this work. Furthermore, temperature stability of this newly obtained bioflocculant and its main components, including protein and polysaccharides, were analyzed by Potassium tartrate-NaOH, H2SO4-Phenol method respectively. Flocculating activity on actual sewerage of the bioflocculant was also determined, where the actual waste waters were sampled from Sibao and Xiangfuqiao Hangzhou, Zhejiang province, PR China.The experimental results showed that flocculating activity raised with the increased biomass of B-9. It reached a maximum when the microorganisms have entered into an stationary phase in cultural 72 hours, and the value decreased at the end of stationary phase. The best harvest time of 72 hours was found in this work for B-9.The glucose, lactose, sucrose and acetic sodium were the good carbon source for the B-9 secreted bioflocculant, and the soluble starch promoted the growth ofB-9 at the same time. The above optimized routine enhanced B-9 biomass production was 50 times of the amount when glucose as the carbon source alone. The influence of citrate sodium on secreting bioflocculant and the growth of B-9 was not found.Both inorganic nitrogen (NH4Cl, (NH4)2SO4, NH4NO3, NaNO3) and (Urea, yeast) promoted the production of bioflocculant. Among the above nitrogen sources, urea increased the flocculating activity to 98.4%, while yeast significantly enhanced the production of B-9 under the same culture conditions.In the C/N ratio range of 2.5 and 5.0, the flocculating activity was kept 95% or above. When the mass ratio of glucose(mg)/nitrogen(mg) varied from 10 to 15, the flocculating activity decreased to some extent. But once the ratio was up to 20, the minor increased flocculating activity was observed. In all experiments in this work, a above 90% flocculating activity was obtained when B-9 was used as culture liquid.The pH factor apparently influenced the flocculating activity of the culture liquid. Once the pH of flocculation system was decreased to 2.0, a low flocculating activity was found. And once the pH was up to 4.0, flocculating activity increased rapidly. This trend was observed till the pH increased to 12.0.Tri or bi-valent cations (Cu2+, Al3+, Mg2+, Fe2+ and Ca2+) in the system preferable increased the flocculating activity; while this effect was not found for sodium ions.When the concentration of CaCb was in lied in the range between 0 and 0.8g/L, the flocculating activity was enhanced with increase of this salt concentration. And the maximum flocculating activity of 96% was observed when the concentration was 0.8g/L. Above the concentration of 0.8g/L, the activity was decreased.Upon heating, the flocculating activity was increased appreciably within the starting 30 min thermal treatment. During the prolonged thermal process, theactivity was decreased at 70 min. But all the activities were higher than that at room temperature, indicating that B-9 had a very high thermal stability.By extraction of the bioflocculant in laboratory, a 3.27g product was obtained, which included polysaccharides (2.03g/L, 62.1%) and protein (0.57g/L, 17.4%).In the treatment of high SS waste water, including secondary sediment pool infall and mill waste water, the bioflocculant showed high flocculating activity (94.7%); while for low SS waste water, secondary sediment pool outfall, the flocculating activity was 64.4%. For the natural water body, Huajiachi Lake, our newly obtained B-9 showed almost no activity.
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