Assistance of Ectoine on Acinetobacter sp. A06 of simultaneous heterotrophic nitrification and aerobic denitrification denitrifying at stress condition

The simultaneous heterotrophic nitrification and aerobic denitrification (SND) performed by Acinetobacter sp. A06 could be inhibited by high salt, high ammonia nitrogen concentrations and extreme pH. To improve the SND nitrogen removal efficiency of Acinetobacter sp. A06 in adverse environment, we investigated the effects on nitrogen removal by Acinetobacter sp. A06 of five compatible solutes. The results show that Ectoine was the best effect in five osmotic compensation solutes when the salt concentration was 15 g/L, 30 g/L, 45 g/L, and 60 g/L, adding Ectoine, nitrogen removal were increased by 21.10%, 26.94%, 14.67% and 11.21%, respectively. When the NH₄⁺-N concentration was 1.5 g/L, 2 g/L and 2.5 g/L, adding Ectoine, the nitrogen removal rate increased by 15.93%, 10.07% and 7.11%, respectively,. When the extreme pH of pH was 5 or 9, adding Ectoine, the nitrogen removal rate was increased by 20.70% and 10.44%, respectively.