Abstract：For screening efficient aerobic denitrifying bacteria, it is studied the suitable growth conditions and the performance of aerobic denitrification, and it is finally provided the theory basis for the biological denitrification about application of the bacteria in the water, using flat line, morphology observation, physiological and biochemical and 16 S r DNA sequence analysis screening to denitrify the genus status of bacteria and examine denitrification performance of the strain under the growth condition of the different nitrogen source, carbon source, p H, temperature, cultivation strains. Efficient denitrifying bacteria QX1 section identified as Arthrobacter sp.. The bacteria under the gas bath shaking table speed 160 r/min is that LB medium + quality volume ratio of 1% acetic acid sodium, the optimal temperature 30 ℃, the optimum p H value 8, strains of alkali, temperature 15 ℃ at low temperature tolerance and 40 ℃ at high temperature tolerance. The growth curve showed that under the condition of suitable cultivation, strains grew into the index after 4 h period, this period maintained about 16 h, strains entered the decline phase after 24 h stable growth, and strains in the synthetic wastewater aerobic training after 48 h, nitrate nitrogen removal rate could reach 89. 92%. The bacteria QXI could be used as alkali resistance, well low temperature resistance and high temperature resistance of efficient denitrification alternative strains, developing low or high temperature area water quality improver would have broad application prospects.

Keyword：aerobic denitrification;Arthrobacterium;isolation and identification;