Synthesis Conditions Of A Microbial Flocculant Producing Bacteria And The Research Of Its Application

Microbial Flocculant is a biological macromolecules that has flocculation activity and secreted by microorganism, with the adventage of efficient, non-toxic, no secondary pollution, etc., Microbial Flocculant is an extensive range of applications of environmentally friendly water treatment agent. Microbial Flocculant has great application value in water treatment, sewage water treatment, post-processing, food fermentation. The chemical composition of microbial flocculant mainly includes proteins, polysaccharides, DNA and other macromolecules. High osmotic pressure, high concentrations of heavy metals, extreme pH, high or low temperatures and other environmental factors may effect its flocculation activity by altering the conformation of bioflocculant. In order to improve the rate of microbial flocculation in these environmental conditions, Studies have reported to improve flocculation activity by increasing use of the amount invested, and adding metal ions. In addition, multi-strain mixed microbial fermentation method for preparing a composite flocculant. It has theoretical and practical significance to protect bioflocculant in extreme environments stable and maintain its activity.This paper identified that the flocculating activity of synthetic strain W03 is high in Kaolin system. It was proved that W03 is the ectoine secretory strain by Nuclear Magnetic Resonance. Compared with identification based on 16S rDNA and Blast, W03 is confirmed as Moderately Halophilic which named Halomonas sp. W03. The composition identify of Halomonas sp. W03 by Nuclear Magnetic Resonance proved that the main Extraction of the bioflocculant is polysaccharide. Based on the results of flocculation activity distribution, this microbial flocculant was identified as extracellular polysaccharide flocculant. The experimental results indicate that:The optimum C and N source, Glucose and (NH4)SO4 are benefit to the Syntheses of Polysaccharide. The optimition of Glucose Concentration is 60 g/L and the concentration of (NH4)2SO4 is 10 g/L, the optimum concentration of NaCl is 60 g/L,and the optimum fermentation conditions of polysaccharide is pH 7.0; Under the optimized conditions, Halomonas sp. W03 resultant of polysaccharide was 17.65 g/L. Experiments had been done to explore the flocculating agent and flocculant and ectoine synergistic flocculation best flocculation system. The flocculation system among the factors influencing the flocculating activity. In kaolin suspension, polysaccharide flocculant flocculation system optimum adding amount was 4%, the optimum flocculation temperature of 30℃, pH value of 8, NaCl of 90 g/L,7 min high flocculating rate of 75.9%; In the synergy of flocculant and ectoine, ectoine amount to 2 mM, the polysaccharide content was 4%,30℃, pH value of 8, and NaCl as 105 g/L flocculating rate of 98.55%. Good reduction effect had been produced by Using Halomonas sp. W03 processing and flue gas desulfurization waste water, landfill leachate.