Abstract:[Objective] To study the effect of Cr(Ⅵ) reduction ability of Serratia sp. S2 under ammonia nitrogen (AN) and nitrate nitrogen (NN) with different concentration. [Methods] Simulated the nitrogen pollution of common environment in the laboratory and added different doses of AN or/and NN to the cultivation system in order to evaluate the effect of different types and concentrations of nitrogen, S2 was cultured in the premise of the Cr(Ⅵ) containing culture. Shake culture at constant 37 °C and measure A600, removal rate of Cr(Ⅵ), amount of AN and NN at a regular intervals. [Results] The growth inhibition of Cr(Ⅵ) to S2 was remittenced under the low and middle AN groups. The decline of S2 was accelerated under the high AN and NN groups. The removal rate of Cr(Ⅵ) and amount of AN among experience and control groups according to the independent effect of AN had no significant relationship. The removal rate of Cr(Ⅵ) of low concentration groups had a significant reduction of more than 10.0% and a increase of 7.1% in high concentration groups according to the independent effect of NN. S2 had the ability to reduce 200 mg/L NN to the level of control groups within 4 h. While AN and NN effect at the same time, AN played a leading role in low concentration groups and NN in high groups during the course of Cr(Ⅵ) reduction. [Conclusion] The presence of AN had no significant effect to the Cr(Ⅵ)-removal ability. Different concentrations of NN had different effect to Cr(Ⅵ)-removal ability. High concentration groups had an advantage effect. S2 had a significant ability of reducing NN.
