游离氨抑制Nitrobacter活性动力学试验

Inhibitory kinetics of free ammonia on Nitrobacter

为探究游离氨(FA)对亚硝酸盐氧化细菌中硝化杆菌属(Nitrobacter)活性抑制动力学影响,本试验采用序批式活性污泥(SBR)反应器,在通过改变系统进水FNA浓度达到富集Nitrobacter基础上,以富含Nitrobacter污泥为对象(宏基因组物种注释和丰度分析显示Nitrobacter占细菌总数40.3%),基于批次试验,考察不同FA浓度梯度下亚硝酸盐氧化过程Nitrobacter比耗氧速率(SOUR)变化规律,进而采用非基质抑制动力学模型对试验数据进行拟合。结果表明,当FA>7.3 mg·L^(-1)时,SOUR随着FA浓度的升高而降低。尤其当FA浓度高于22.2 mg·L^(-1)时,SOUR降为0gN·(g VSS·d)^(-1),最大比耗氧速率为0.62 g N·(g VSS·d)^(-1)。此外,基于Nitrobacter活性抑制程度判断,FA抑制Nitrobacter活性抑制类型符合非竞争性可逆抑制动力学。

A sequencing batch reactor(SBR)was operated in this study to investigate the inhibitory kinetics of free ammonia(FA)on Nitrobacter.At the beginning of the experiment,FNA concentration in influent was changed to enrich Nitrobacter.Meanwhile,metagenomic species annotation and abundance analysis showed that Nitrobacter accounted for 40.3%of the total bacterial population.Then,the sludge enriched of Nitrobacter was used to study the variation rule of the specific oxygen uptake rate(SOUR)during nitrite oxidation process of batch tests.Furthermore,non-substrate inhibition model of FA inhibition on Nitrobacter activity was fitted.The results showed that the SOUR decreased with the increase of FA concentration as FA>7.3 mg·L?1.In particular,the SOUR was maintained at 0 g N·(g VSS·d)?1 when FA concentration was higher than 22.2 mg·L?1.Moreover,maximum specific oxygen uptake rate was 0.62 g N·(g VSS·d)?1.In addition,based on the degree of inhibition of Nitrobacter activity,the inhibition type of FA inhibition on Nitrobacter activity is in accordance with non-competitive reversible inhibition kinetics.