反硝化耐冷菌Acinetobacter johnonii DBP-3的低温除磷特性

通过批实验技术研究了不同条件下一株反硝化耐冷菌Acinetobacter johnonii DBP-3(Genbank登录号JN314436,保藏号CGMCC4753)的低温除磷特性.结果表明,菌株可分别利用氧气(O2)、硝酸根(NO3-)和亚硝酸根(NO2-)为电子受体吸收溶液中的磷酸盐,不同电子受体条件下吸磷效能的大小顺序为:氧气>硝酸根>亚硝酸根.NO3-的浓度为0～150mg·L-1时,菌株对磷酸盐的吸收能力随着NO3-浓度的增加而增加.亚硝酸盐浓度为0～20mg·L-1时菌株对磷酸盐的吸收能力随NO2-浓度的增加而明显增加;浓度为20～60mg·L-1时,菌株对磷酸盐的吸收能力受NO2-浓度的影响较小;浓度达80mg·L-1时,菌株的除磷能力明显下降.不同碳源条件下厌氧培养的菌体细胞在缺氧条件下培养时对磷酸盐的去除能力大小顺序为:乙酸钠>柠檬酸钠>葡萄糖.菌株除磷的适宜pH值范围为7～9.温度为5℃时,菌株仍保持一定的除磷能力,随着温度的升高除磷能力逐渐增加,当温度达35℃时,除磷能力开始下降.菌株对盐度的耐受性在好氧培养时大于缺氧培养.缺氧培养48h,菌体细胞中磷的平均含量可达5.7%,而厌氧培养的菌体细胞中磷的最低含量为2.6%,表现出了明显的聚磷和释磷特性.研究结果可为低温富营养化水体或富氮磷污水的生物处理提供理论依据.

Characterization of phosphate removal by the psychrotolerant denitrifying bacterium Acinetobacter johnonii DBP-3 at low temperature

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.