可用于水体污染控制的氨氮转化菌筛选及部分降解特性的实验研究

从南京禄口水产养殖基地淡水鱼塘取淤泥作为分离菌株的土源,采用选择性富集培养法,从中分离到能以硫酸铵为氮源的菌株7株,对7个菌株进行氨氮降解实验,它们氨氮转化率分别为14.8%、19.7%、53.4%、94.2%、29.1%、63.5%和41.7%,其中AN-4菌株的转化率最高且生长良好。通过AN-4菌株16S rRNA基因序列分析以及生理生化方法,鉴定此菌株为克雷伯氏菌属(Klebsiellasp.)。对菌株AN-4转化氨氮的特性及温度、pH值、氨氮初始浓度和菌株接种量对其氨氮转化率的影响研究,结果表明,菌株AN-4降解氨氮的最适条件为:温度为30℃和pH值为8.0;当氨氮初始浓度为30mg/L时,AN-4菌株在24 h内的氨氮降解率可达85%以上,且能耐受高达200 mg/L的氨氮浓度;AN-4活化菌液浓度为108cfu/mL,当接种量为3×106cfu/mL时,AN-4菌株在24 h内的氨氮降解率为87.75%。综合上述结果,符合淡水养殖水环境条件,说明AN-4菌株适合在水产养殖中应用,为将菌株AN-4应用于水产养殖环境修复提供了理论依据。

Experimental study on screening and some characterization of an ammonia nitrogen transformation strain used for water pollution control

A sludge sample was obtained from a pond in freshwater fish aquaculture base of Lukou, Nanjing. The sample was later analyzed for isolating strains capable of degrading ammonia nitrogen. Seven strains were isolated by selective enrichment culture, and were separated by using ammonium sulfate as nitrogen source.The ammonia nitrogen conversion rates of seven strains were 14.8% , 19.7% , 53.4% , 94. 2% , 29. 1% ,63.5% and 41.7% , respectively. Conversion rate of strain AN-4 was highest up to 94.2%. Strain AN-4 was identified as Klebsiella sp. by means of 16S rRNA gene sequence analysis and morphological and physical-biochemical methods. The ammonia nitrogen degradation characteristics of strain AN-4 and effect factors on ammonia nitrogen degradation rate, such as temperature, pH, initial concentration of ammonia nitrogen and the inoculum size, were studied. The results showed that the optimum degradation conditions for AN-4 were 30℃ and pH 8.0,respectively. It could grow in a media with ammonia nitrogen up to 200 mg/L. Strain AN-4 could degrade ammonia nitrogen of 30 mg/L up to 85% in 24 hours. Concentration of activated strain AN-4 was 10~8 cfu/mL. It could degrade ammonia nitrogen up to 87.75% in 24 hours with 3% inoculum size. In conclusion, the research showed that the strain AN-4 could be used in freshwater aquaculture. In addition, this research provided a theoretical basis of the strain AN-4, which was used in aquaculture environmental remediation by identification of the strain AN-4 and exploration of degradation rule of ammonia.