Lanthanum-(La(III)) concentration in water resources is increasing exponentially in recent years following its widespread use as farm inputs via crop fertilizer production. However, studies on the effects of La(III) on nitrogen removal, conversion and mechanism are still unclear. Consequently, this study investigated the effects of La(III) on partial-nitritation-(PN) process performance and bacteria activities via sludge morphology, extracellular polymeric substance (EPS) composition, organic functional group changes, and microbial community structure. The study revealed hormesis condition within the PN batch assays upon La(III) dosage, thus, dose-response phenomenon exhibited sludge stimulation at low La(III) dosage and inhibition at high-dose. Scanning electron microscope-energy spectroscopy (SEM-EDX), confocal laser scanning microscope (CLSM), and Fourier transform infrared spectroscopy (FTIR) confirmed efficient removal of La(III) (96.76%-99.93%) was achieved with polysaccharide and polysaccharide-protein complex through biosorption and biosynthesis. 16S rRNA gene sequencing demonstrated that La(III) significantly promoted the abundance of Nitrosomonas and identified Aquamicrobium as the ammonia oxidizing bacteria with high tolerance to La(III). Furthermore, phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) further revealed metabolic detoxification as pathways where enzymatic reactions neutralized and solubilized toxins. This study unraveled a strategic approach and insight into how Nitrosomonas and other functional genera regulate and control their activities against La(III) toxicity and subsequently enhance the PN process.

镧（La（III））在水资源中的浓度在近年来通过农作物肥料生产广泛用作农业投入物之后呈指数级增长。但是，关于La（III）对脱氮，转化率和机理的影响的研究仍不清楚。因此，本研究通过污泥形态，细胞外聚合物（EPS）组成，有机官能团变化和微生物群落结构，研究了La（III）对部分硝化（PN）过程性能和细菌活性的影响。该研究揭示了在La（III）剂量下PN批次测定中的兴奋状态，因此，剂量响应现象在低La（III）剂量下表现出污泥刺激作用，在高剂量下表现出抑制作用。扫描电子显微镜-能谱（SEM-EDX），共聚焦激光扫描显微镜（CLSM），傅里叶变换红外光谱（FTIR）证实，多糖和多糖-蛋白质复合物通过生物吸附和生物合成可有效去除La（III）（96.76％-99.93％）。16S rRNA基因测序表明La（III）显着促进了亚硝酸盐杆菌并鉴定出水产微生物是对La（III）具有高度耐受性的氨氧化细菌。此外，通过未观察到的状态重建（PICRUSt）对群落的系统发育研究进一步揭示了代谢解毒作为酶反应中和和溶解毒素的途径。这项研究揭示了战略方法和洞察亚硝化单胞菌和其他功能属如何调节和控制其抗La（III）毒性的活动，并随后增强PN过程。