Isolation And Identification Of Denitrifying Polyphosphorus Bacteria And Its Removal Of Nitrogen And Phosphorus

Algal bloom has occurred frequently in some of main lakes in recent years and shows the trend to occur in northern area in China, which has become the urgent environmental problem to be solved. The accumulation of nutrient in water body at low temperature must be solved in order to govern fundamentally eutrohpic water body. However, the recent studied has focus on the transformation and stabilization of nutrient in water body by plant and microorganisms during the outbreak period of algal bloom and ignored the important role of psychrotrophs in the bioremediation of eutrophic water body. The denitrifying polyphosphorus bacteria possess higly adaptive capacity for the level of dissolved oxygen and temperature and has been paied much attention to. So, the paper targets the bioremediation of eutrophic water body at low temperature, screened and identified aerobic denitrifying polyphosphorus bacteria and studied the removal characterization of nitrogen and phosphorus in culture fluid and water samples under different condtions, which can provide theoreticl basis for the water conservation. The main conclusions of the paper are as follows:1 Three strains of denitrifying polyphosphorus bacteria has been screened from the eutrohpic water body, using low-temperature-oriented acclimatization culture. One strain was selected as the experimental bacterium and named as DBP-3,which showed the ability to grow rapidly and effectively remove nitrogen and phosphorus and has been identified as Acinetobacter johnsonii based on the colony character, physiological and biological reaction and analysis of phylogeny.2 The optimum growth temperature for strain DBP-3 is 20℃. The strain can grow well in the temperature range of 10 to 30℃and can maintain the ability to grow at 5℃. The strain can grow well at pH from 7.0 to 9.0 and the growth has been inhibited with the increasing and decreasing of pH values. In oligotrophic conditions, the strain remains actively growing. The strain can use well sodium citrate as the carbon source at 10℃.Strains have a certain adaptability adaptability of the salinity.Under the good oxygen and aerobic condition, the bacterial growth was inhibited when the salinity is 10% and 5%.3 Under the good oxygen condition, the strain growth rate and the denitrification gather phosphorus ability to be higher than the anoxic condition obviously. After 10℃under the good oxygen raises 60h, in the nutrient fluid the nitrate nitrogen's and total phosphorus's elimination rate may reach 82.0% and 87.8%, after the oxygen deficit raises 60h, the nitrate nitrogen's and total phosphorus's elimination rate is 71.1%and 77.4%.4 The Strain has resistant to chloramphenicol, ampicillin, neomycin and penicillin pioneer, and has no resistance to tetracycline and rifampicin.The strain has the strongest resistance to adriamycin, and the strain shows high resistance for cephalosporin and can grow well even at the concentration of 1024.0mg/L. The strain has the lowest resistance to rifampin, the strain shows significant adverse effect when the concentration of tetracycline and reifampicin is 2.0mg/L, respectively.5 Under good oxygen and anoxic condition, when the phenol density increases to 10.0mg/L, the strain growth has received the obvious and inhibitory the extremely remarkable action. There is the toxic to the effect of phenol on the strain:anoxic condition> aerobic condition.6 The toxic effect of mercury is greater than arsenic to the strain. When the mercury density is 3.0mg/L and the arsenic density is 200.0mg/L, has had the obvious influence to the strain growth and denitrogenation. The toxic effect of chlorpyrifos is greater than carbendazim to the strain. When the chlorpyrifos density is 100.0mg/L and the carbendazim density is 30.0mg/L, has had the extremely remarkable and obvious influence to the strain growth and denitrogenation.7 The strain indicates to the farmland runoff pollution river water nitrogen and the phosphorus elimination experiment, throws the strain in the sterilized water and original water sample the nitrogen elimination rate is 77.9% and 70.0%, and the phosphorus elimination rate is 84.9% and 77.1%. The strain has certain compatibility in the farmland runoff water by add to the Strain in water.