湖库沉积物好氧反硝化菌群脱氮特性及种群结构

好氧反硝化菌是水环境生物修复的热点研究领域,本研究从西安市金盆水库、兴庆公园和长乐公园采集沉积物,在运用传统的间歇曝气富集和选择培养基筛选好氧反硝化菌的基础上,引入超声波预处理沉积物-水悬液,成功筛选出3组高效好氧反硝化菌群H-30、X-10和C-30,并对其反硝化能力进行研究.结果表明,该3组混合好氧反硝化菌群具有高效的脱氮能力,在溶解氧为(7.2±0.6)mg·L-1的培养基中,好氧反硝化菌群H-30、X-10和C-30总氮(TN)去除率分别达到83.04%,83.40%和82.68%,仅有少量亚硝氮(NO-2-N)积累.Illumina高通量DNA测序结果表明,3组nir S型好氧反硝化优势混合菌群种群结构差异显著,H-30,X-10和C-30菌群的优势菌种分别是枯草芽孢杆菌(Bacillus subtilis),Paracoccus pantotrophus和斯氏假单胞菌(Pseudomonas stutzeri),其中斯氏假单胞菌(P.stutzeri)在H-30、X-10菌群中所占比例差异不显著,Pseudomonas xiamenensis仅存在于H-30.本研究筛选的3组高效好氧反硝化菌群将为城市内湖污染水体的微生物修复工程提供菌源保障.

Denitrification Characteristics and Community Structure of Aerobic Denitrifiers from Lake and Reservoir Sediments

The effect of aerobic denitrifying bacteria is a hot topic in the field of water environment bioremediation. Aerobic denitrifier communities, H-30, X-10, and C-30, enriched by intermittent aeration, screened with screening culture media, and treated by ultrasonic waves, could perform high denitrification performance at the higher dissolved oxygen concentration of (7.2±0.6) mg ·L^-1. The total nitrogen (TN) removal rate of aerobic denitrifier communities, H-30, X-10, and C-30, reached 83.04%, 83.40%, and 82.68%, respectively. There is lower nitrite accumulation during the process of denitrification. Illumina high-throughput DNA sequencing revealed that aerobic denitrifier compositions were significantly different among the three communities. The predominant strains of aerobic denitrifier communities, H-30, X-10, and C-30, were Bacillus subtilis, Paracoccus pantotrophus, and Pseudomonas stutzeri, respectively. The proportion of P. stutzeri in aerobic denitrifier communities H-30 and X-10 was almost the same, while Pseudomonas xiamenensis was only detected in H-30. These three efficient aerobic denitrifier communities provide a bacterium source guarantee for polluted water bioremediation of lakes and reservoirs in cities.