羟胺对厌氧氨氧化污泥群落的影响

目前,由于厌氧氨氧化(anaerobic ammonium oxidation,ANAMMOX)过程具有高效率、低能耗和污泥量少的优点,在污水除氮方面具有广阔的应用前景.羟胺既是厌氧氨氧化代谢的中间产物,同时也是一种抑制剂,但是目前关于厌氧氨氧化细菌颗粒如何应对羟胺的压力还没有很好的解释.通过羟胺批次添加实验,发现在投加不同浓度的羟胺情况下(40～80mg·L~(-1)),厌氧氨氧化的反应活性受到了抑制作用,但是无法判断厌氧氨氧化细菌对羟胺的耐受阈值.然后基于实时荧光定量聚合酶链反应(RT-qPCR)技术检测了不同反应器内肼氧化酶(HZO)的mRNA的表达量,发现HZO酶的表达量随着羟胺浓度的增加出现先升高后降低的趋势,由此本研究推测相对于3.12g·L~(-1)的厌氧氨氧化颗粒污泥,其承受的羟胺浓度(以N计)阈值介于60～70mg·L~(-1).同时利用16S rRNA高通量测序的方法对反应器内的颗粒污泥微生物结构与功能进行分析,发现投加适量的羟胺(50mg·L~(-1))有助于增强颗粒污泥中细菌的细胞运动性,促进厌氧氨氧化细菌的组成,提供一个更佳的生态平衡.

Effect of Hydroxylamine on Community of ANAMMOX Sludge

At present, the anaerobic ammonium oxidation (ANAMMOX) process has the advantages of high efficiency, low energy consumption, and low sludge quantity, and it therefore has broad application prospects in sewage nitrogen removal. Hydroxylamine is not only an intermediate product of ANAMMOX metabolism but also an inhibitor. However, the effect of hydroxylamine on the activity of ANAMMOX is not clear. Therefore, we investigated the ANAMMOX activity under the condition of adding different concentrations of hydroxylamine (40-80 mg·L^-1) through a hydroxylamine batch experiment. It was found that hydroxylamine can inhibit ANAMMOX activity. However, it was impossible to determine the threshold of ANAMMOX bacteria to hydroxylamine. Next, the mRNA levels of hydrazine oxidase (HZO) in different reactors were detected by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR), and it was found that the expression levels of HZO peak and then decrease with an increase of hydroxylamine concentration. It was suggested that the tolerated hydroxylamine concentration was within 60-70 mg·L^-1 for 3.12 g·L^-1 ANAMMOX granular sludge. Moreover, a 16S rRNA high-throughput sequencing method was used to analyze the structure and function of ANAMMOX granules in microbial communities in the reactor. It was found that the addition of an appropriate concentration of hydroxylamine (50 mg·L^-1) helped to enhance the cellular motility of bacteria and promoted the composition of ANAMMOX bacteria, providing a better ecological balance.