Identification and characteristics of a strain of bacteria with highly-effective nitrite nitrogen removing

Abstract:

[Objective] A strain of bacterium, strain FP6, with the high ability of removing nitrite nitrogen was isolated from the bottom of the shrimp pond, and its phylogeny and denitrifying characteristics were studied. [Methods] Sequence of the 16S rRNA gene, physiological and biochemical properties were analyzed. Factors that affected the denitrifying ability of strain FP6 were investigated, including carbon sources, C/N ratio, initial pH, temperature, shaker speed and NaCl concentration. Moreover, the ability to remove ammonia and nitrate of the strain was also studied. [Results] Among the isolated strains, strain FP6 showed the highest ability to remove nitrite nitrogen and was identified as Bacillus licheniformis. Sucrose was identified as the best carbon source for its growth and denitrification. Under the conditions of C/N ratio 15?25, initial pH 7.0?10.0, temperature 20 °C?37 °C, shaker speed 0?200 r/min and NaCl concentration 0?40 g/L, strain FP6 kept high removing nitrite nitrogen ability. Strain FP6 showed the ability of removing ammonia and nitrate and no nitrite nitrogen was accumulated when removing nitrate. [Conclusion] Strain FP6 possesses excellent removing nitrite nitrogen ability, with wide range of temperature, pH and salinity.

Key words:Nitrite nitrogen, Bacillus, Isolation and identification, Denitrification