Characterization of phosphate removal by the psychrotolerant denitrifying bacterium Acinetobacter johnonii DBP-3 at low temperature
反硝化耐冷菌Acinetobacter johnonii DBP-3的低温除磷特性

Under different conditions,the removal of phosphate by a psychrotolerant denitrifying bacterium Acinetobacter johnonii DBP-3(JN314436,CGMCC 4753) was studied by using batch testing experiment.Results showed that strain DBP-3 took up phosphate based on three types of electron acceptors in the order of oxygen > nitrate > nitrite.The capacity of stain DBP-3 in taking up phosphate ranged from 0 to 150 mg · L-1,and increased with increased nitrate concentration.On the other hand,phosphate removal rate obviously increased with the increased nitrite concentrations,which ranged from 0 to 20 mg · L-1;but there was no significant increase in the phosphate removal rate at nitrite concentration from 20 to 60 mg · L-1 and the rate of phosphate removal inversely decreased when the nitrite concentration increased over 80 mg · L-1.In anoxic condition,the removal rate of phosphate by cells of strain DBP-3 grew in cultural fluids with different sole carbon sources,following the order of sodium acetate > sodium citrate > glucose.The suitable range of pH value for strain DBP-3 in removing phosphate from cultural fluids was from 7 to 9.It should be noted that the strain DBP-3 removed phosphate even at 5 ℃ and the phosphate removal increased with the increased temperature from 5 to 30 ℃.However,the removal rate of phosphate decreased when the temperature increased to 35 ℃.Strain DBP-3 was more resistant to salinity in aerobic condition than in anoxic condition.The average phosphate content in cells of strain DBP-3 was up to 5.7%,after 48 h of anoxic incubation.In contrast,the lowest phosphate content in cells was 2.6% under anaerobic culturing condition.These showed that strain DBP-3 was one kind of phosphate accumulating /releasing microorganism.This study could provide theoretical basis for the biological treatment of eutrophic water body and nitrogen-and phosphate-rich sewage.