一株高效去除亚硝酸氮细菌的分离鉴定及其脱氮特性研究

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

【目的】从南美白对虾养殖塘中分离到高效去除亚硝酸氮的细菌,对其分类和脱氮特性进行了研究。【方法】以除亚硝酸氮为主要指标,取养殖塘底层水样分离筛选菌株;依据16S rRNA基因序列和生理生化特征初步鉴定菌株;研究不同碳源、碳氮比、起始pH、温度、摇床转速和氯化钠浓度对反硝化除亚硝酸氮的影响,并考查了菌株对硝酸氮和氨氮的利用情况。【结果】得到的菌株中菌株FP6活性最高,初步鉴定菌株FP6属于地衣芽孢杆菌。菌株FP6的生长最适脱氮碳源为蔗糖,菌株FP6去除亚硝酸氮有高活性的条件范围为:C/N值15 25、起始pH 7.0 10.0、温度20°C 37°C、摇床转速0 200 r/min和氯化钠浓度0 40 g/L。菌株FP6对硝酸氮和氨氮都有一定的去除能力,利用硝酸氮时不积累亚硝酸氮。【结论】地衣芽孢杆菌FP6具有优良的除亚硝氮特性,适宜的温度、pH和盐度范围较宽。

[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 ℃-37 ℃, 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.