Screening and growth condition optimization of anoxic denitrifying phosphorus removal bacteria Xun X.

Sludge from an SBR enhanced biological phosphorus removal device was studied to screen the denitrifying phosphorus removal bacteria(DPB) Xun X.Its taxonomic status was determined by traditional and molecular biology technology.Response surface methodology was used to optimize the growth conditions of Xun X.Physiological and biochemical properties of Xun X show its anoxic denitrifying and phosphorus removal function.It is most similar to Escherichia coli,according to morphological observation,culture characteristics,physiological and biochemical properties and the sequencing result of 16S rDNA.There is 99.9% homology of sequence.Therefore,Xun X(Escherichia coli) is a kind of anoxic DPB.Response surface results show that the order of key factors affecting the growth of Xun X is(ρ(carbon source))pH(ρ(nitrogen source).) The mass concentration of carbon source is the only significant influencing factor in the second item,and it decides the growth of Xun X.The best growth conditions of Xun X are the mass concentration of carbon source(sodium acetate + glucose) 3.48(gL),nitrogen source(ammonium sulfate + peptone) 1.22(gL),and pH=8.00.The average measured turbidity of the bacteria is 0.732 under the growth condition.