The characteristics of nitrate removal by the psychrotolerant denitrifying bacterium Acinetobacter johnonii DBP-3, isolated from a low-temperature eutrophic body of water

Abstract

A psychrotolerant denitrifying bacterial strain, DBP-3, was isolated from a eutrophic body of water by low-temperature-oriented acclimation culture. Based on its morphologicalandbiochemicalcharacteristics and 16S rDNA gene sequence, the bacterium was identified as belonging to the genus Acinetobacter and closely related to A. johnonii. The satisfactory growth of DBP-3 was observed at 10–30°C and pH 7–9. Strain DBP-3 was able to utilize three types of carbon sources (sodium acetate > sodium citrate > glucose) to support growth and denitrification. DBP-3 grew faster, but with lower nitrate removal efficiency and higher nitrite accumulation, under aerobic conditions than under anoxic conditions. DBP-3 was extremely susceptible to tetracycline and rifampicine and less sensitive to ampicillin and penicillin. The growth of DBP-3 was significantly affected by Hg (II), Cr (VI), Pb (II), Cd (II), and As (III) at 0.32, 0.63, 1.25, 2.5, and 25.0 mg L⁻¹, respectively. Interestingly, chromium (VI) significantly promoted DBP-3 growth at concentrations lower than 0.32 mg L⁻¹. These data may be helpful to support the use of strain DBP-3 in the purification of eutrophic water bodies at low temperatures.

Keywords :

• Psychrotolerant
• low temperature denitrification
• Acinetobacter johnonii
• antibiotic
• heavy metal

Acknowledgments

This work was supported by the Scientific and Technological Developing Scheme of Jilin Province, China (20100141 to M. T. Li), National Natural Science Foundation of China (51109089 to M. T. Li), and Frontier Science and Interdisciplinary Innovation Projects of Jilin University, P.R. China (201003061 to L. L. Hao).