一种耐热亚硝化单胞菌富集培养物的特性及其在污水中的脱氨效果

从生活污水中分离得到了一种自养氨氧化菌富集培养物，其中的唯一的自养氨氧化菌为Nitrosomonas nitrosa SN-6，其16S rDNA序列和amoA基因序列均与N. nitrosa Nm90高度相似(Identity达100%).该文研究了高温对该富集培养物在培养基和垃圾渗滤液中代谢与生长的影响，并测定了游离亚硝酸浓度和盐度对其脱氨效果的影响及该菌对污染地表水的脱氨效果.结果表明：该富集培养物的最高耐受温度不低于43 ℃，最大亚硝氮积累速率可达129 mg·L－1·d－1；在培养基中的最适生长温度为37～40 ℃(代时低至6.1 h)，在垃圾渗滤液中的最适生长温度为40 ℃(代时低至5.9 h)；该富集培养物脱氨活性的半数抑制盐度略高于1%，半数抑制游离亚硝酸浓度约为0.095 mg·L－1；仅需3 d即可使污染地表水中的氨氮从5～23 mg·L－1降至不超过1.5 mg·L－1.结果表明，SN－6不但适于高温高氨水体，也适于中温低氨水体脱氨，具有广泛的应用前景.

Characteristics of a heat-resistant Nitrosomonas enrichment culture and its ammonia-removing ability in various waste waters

An enrichment culture of autotrophic ammonia oxidizing bacteria was isolated from domestic wastewater. The only one strain of autotrophic ammonia oxidizing bacteria in the enrichment culture was named as Nitrosomonas nitrosa SN-6 because its 16s rDNA sequence and amoA gene sequence was highly similar to N. nitrosa Nm90 at an identity of 100%. The influences of high temperature on the activity and growth of N. nitrosa SN-6 were studied both in medium and in landfill leachate. The influences of free nitrous acid and salinity on its ammonia removing ability were studied. Also， the ammonia-removing ability was measured in polluted ground water. The results showed that the highest tolerance temperature of the enrichment culture was no less than 43 ℃，and the maximum NO-N accumulation rate reached 129 mg·L－1·d－1. Moreover，the optimum growth temperature was 37-40 ℃ in medium (with the doubling time of 6.1 h)， and was 40 ℃ in landfill leachate (with the doubling time of 5.9 h). The IC50 of deammoniation by salinity was a little more than 1%，and the IC50 of deammoniation by free nitrous acid was about 0.095 mg·L－1. Moreover， in polluted ground water， the initial NH3-N decreased from 5-23 mg·L－1 to less than 1.5 mg·L－1 in 3 days. The above results demonstrated that SN-6 was not only suitable for high NH3-N concentration at high temperature， but also suitable for low NH3-N concentration at normal temperature， which suggests a great advantage in application.