In a recent study, the nitrification performance, metabolic activity, antioxidant enzyme activity as well as bacterial community of mixed nitrifying bacteria culture under different temperature dropping strategies were evaluated using 16S gene sequencing.

It was shown that acclimation at 20°C for 6 days allowed better maintenance of nitrification activity at 10°C. The nitrite oxidation capacity of nitrifiers was significantly correlated with the relative light unit (RLU) (p<.05) and the fluctuation of superoxide dismutase (SOD) enzyme activity (p < .01). Samples with serial #3 showed the highest RLU levels and the least SOD enzyme fluctuation as compared to serials #2 and #4. Throughout the experimental period, Nitrosospira and Nitrosomonas as well as Nitrospira were identified as the predominant ammonia-oxidizing bacteria (AOB) and nitrate-oxidizing bacteria (NOB). The dynamic change of AOB/NOB ratios and nitrification activity in serials #2-#4 demonstrated that AOB recovered better than NOB with long-term 10°C exposure, and the nitrification performance was mainly limited by the nitrite oxidation capacity of NOB.

Scientists conclude that 6 days acclimation at 20°C was beneficial for the mixed nitrifying bacteria culture to cope with low temperature (10°C) stress, possibly due to the maintenance of metabolic activity, antioxidant enzyme activity stability, as well as appropriate AOB/NOB ratio.


M. Chen, Y. Chen, S. Dong, S. Lan, H. Zhou, Z. Tan, X. Lia (2017) Mixed nitrifying bacteria culture under different temperature dropping strategies: Nitrification performance, activity, and community Chemosphere doi: 10.1016/j.chemosphere.2017.12.129 [abstract]

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