Study On Isolation And Characteristics Of Bioflocculation Bacteria

Microbial flocculent as known as the third generation of flocculent,which through take extraction,purification and obtain in the enrichment of some types of microbes or their secretions.Microbial flocculent is a new type of water treatment agent with high efficient,natural degradation,non-poisonous and without pollution into the environment.Microbial flocculants have a wide range of application,high flocculating activity,and most of them are mostly affected by temperature,pH and ionic strength.In this study,plate dilution method and separation were used to screen efficient bioflocculant producing bacteria also studied the biological characteristics and flocculation producing strains,obtain the following results:(1)In this paper,three strains bacteria were separated from laboratory activated sludge,strawberry soil,Youth park soil and NanHu park sediment.These three strains are named YS1,YQ1 and YC3 which with high flocculation effect of kaolin suspensions can reach 85.7%,90.8%and 91.7%.By observing these strains characteristics,physiological and biochemical test,16 S rDNA sequence analysis,YS1 was identified as Delftia sp,YQ1 and YC3 were the same strains,both belong to p.Paenibacillus and named Paenibacillus shenyangensis sp.nov.(2)By taking single factor experiment,the culture conditions of YS1 and YQ1 were optimized.The results of optimal culture conditions showed that:temperature range for YS1 is 30-35?,pH 5-7 and concentration of NaCl 0-2%;temperature range for YQ1 is 30-35?,pH 5-8,concentration of NaCl 0-4%and carbon source is mannose.(3)Taking YQ1 and MBFYQ1 as the research object,this paper studied YQ1 tolerance to high temperature and thermal stability of MBFYQ1.The results showed that YQ1 had resistance to high temperature,after heating 30min in 65 ? with water bath and then YQ1 had been dead;MBFYQ1 took a certain thermal stability at a high temperature.After heating MBFYQ1 20min in 80? with water bath,it can also get flocculating rate of 73.4%.By analyzing composition of MBFYQ1with infrared spectrum,the material which has flocculation ability was macromolecular polysaccharide.(4)Removal of MBFYQ1 on inorganic waste water was studied.To use mannitol as source of carbon,with culture time 48h,agitation rate 150r/min,dosing 5%(v/v)MBFYQ1 into 50mg/L Pb2+ water,can get removal rate of 88%.With pH 6,dosing 0.1%(v/v)MBFYQ1 into 5g/L ash water(0.074mm),can get removal rate of 95%.According to scanning electron microscopy and infrared spectroscopy of MBFYQ1 capturing Pb2+,the results showed that the speculation was likely to chelate the active groups in MBFYQ1 and Pb2+to form chelation.