为了研究微生物对水体中氨态氮的去除能力,通过多点采样、高浓度氨态氮废水驯化、梯度稀释、平板划线分离等步骤,从土壤中分离并筛选出对氨态氮具有高降解能力的菌株,并对其形态特征、生理生化特征进行了鉴定.对菌株最佳生长条件进行了研究,并将菌株投入模拟污水及养殖污水研究其氨态氮降解特性.在以硫酸铵为唯一氮源的筛选培养基上筛选分离到1株对氨态氮具有高降解率的菌株N9,初步鉴定该菌株为枯草芽孢杆菌(Bacillus subtilis),菌株降解氨态氮最适温度为30℃,最适pH7.0；其生长与氨态氮降解过程同步,随着模拟废水中氨态氮浓度下降,细菌湿重不断增加；在模拟废水中,当氨态氮初始浓度为50 mg/L时,48 h内的氨态氮降解率可达95.5％；养殖水体氨态氮降解试验结果表明,在氨态氮初始浓度为2.3 mg/L、接种量105 CFU/L时,6d内氨态氮降解率可达85.2％.可见N9菌株降解氨态氮能力显著,可用于氮态氮污染的治理.%To study the removal of high-concentration ammonia-nitrogen by microorganism, multi-point sampling, domestication of high-concentrations ammonia-nitrogen, gradient dilution of domesticated liquid and isolation from streaking plate were conducted to isolate heterotrophic nitrifiers from soil. A Bacillus isolates good at degrading ammonia-nitrogen was isolated on the selective medium with (NH4)2SO4 only. The strain was identified through morphological, physiological and biochemical tests. The best growing conditions for the strain and its degrading characteristics in simulated wastewater and aquaculture water were studied. According to morphology characteristics and the results of physiological and biochemical experiments, the strain name N9 was identified as Bacillus subtilis. The optimum temperature and pH value for strain N9 to degrade ammonia-nitrogen were 30℃ and 7.0 respectively. The growth of strain N9 and the degradation of ammonia-nitrogen were synchronous. The wet cell weight of strain N9 generally increased as the concentration of ammonia-nitrogen decreased. In simulated wastewater containing ammonia-nitrogen 50 mg/L, ammonia-nitrogen was degraded by 95. 5% in 48 h. When the initial concentration of ammonia-nitrogen was 2. 3 mg/L in aquaculture water, the ammonia-nitrogen could be removed by 85. 2% within 6 d by 105 CFU/L strain N9, moreover, the N9 strain could use many carbon-containing compounds as carbon source for growth. It was indicated that the capabilily of N9 to degrade ammonia-nitrogen was strong, and the strain N9 could be used in ammonia-nitrogen pollution control.
展开▼
