高温和高盐对Nitrosomonas nitrosa WH-1氨氧化活性的联合影响

自养氨氧化细菌是污水处理中的重要细菌，但高温和高盐对其氨氧化活性的联合影响研究仍较为匮乏.该文以纯培养的自养氨氧化细菌Nitrosomonas nitrosa WH-1为例，采用响应面法测定了温度与盐浓度对N.nitrosa WH-1亚硝氮积累速率的联合影响，还测定了不同盐浓度条件(3～18 g·L^-1)和不同温度条件(36℃～48℃)下的最适温度、半数抑制温度和半数抑制盐度.发现高温与高盐对亚硝氮积累速率存在明显的交互作用，当温度由36℃升至42℃,半数抑制盐浓度由8.84 g·L^-1增至10.45 g·L^-1,而盐浓度为15～18 g·L^-1时的最适温度和半数抑制温度也显著高于盐浓度为3～12 g·L^-1时的情况.上述结果说明，高温可以缓解高盐所引起的抑制，且适度的高盐也可以提高自养氨氧化细菌的耐热性.

Combined effect of high temperature and high salinity on ammonia oxidation activity of Nitrosomonas nitrosa WH-1

Autotrophic ammonia-oxidizing bacteria are important bacteria in wastewater treatment， but studies on the combined effects of high temperature and high salt on their ammonia-oxidizing activity are still relatively scarce. In this paper， with a purified ammonia oxidizing bacteria Nitrosomonas nitrosa WH-1 as the research object， the combined effects of temperature and salt concentration on nitrite accumulation rate were determined by response surface methodology. According to the nitrite accumulation rate under different salt concentrations (3～18 g·L－1) and different temperatures (36 ℃～48 ℃) conditions， optimum temperature， IC50 of temperature and IC50 of salt concentration to the ammoxidation activity was calculated. The results indicated that there was an significant interaction between high temperature and high salinity on the NO2(－)-N accumulate rate. When the temperature increased from 36 ℃ to 42 ℃， the IC50 of salt concentration increased from 8.84 g·L－1 to 10.45 g·L－1. Moreover， the optimum temperature and the IC50 of high temperature were significantly higher when the salt concentration was 15～18 g·L－1 comparing to the salt concentration of 3～12 g·L－1. The above results suggested that high temperature would alleviate the inhibition caused by high salinity， and moderate high salinity would also improve the heat resistance of ammonia oxidizing bacteria.