高浓度重金属的影响和功能微生物的损失通常会影响废水处理系统中的脱氮过程。在研究中,分离出一种独特的自动聚集好氧反硝化菌(假单胞菌Stutzeri菌株YC-34),具有潜在的Cr(VI)生物吸附和还原应用。通过测定菌株培养过程中无机氮的浓度变化和扩增关键反硝化功能基因,确定菌株的脱氮效率和反硝化途径。自动聚合索引的变化,疏水性指数,采用胞外聚合物(EPS)特征指标评价菌株的自聚集能力。对反硝化过程中镉的生物吸附能力和机理进行了进一步研究。测量了镉的耐受性和吸附指数的变化,并分析了细胞表面的微观特征变化。该菌株表现出优异的脱氮能力,以54mg/L硝酸盐氮为初始氮源,无氨氮和亚硝酸盐氮积累,达到90.58%的脱氮效率。30%的初始硝酸盐-氮转化为N2,并且仅产生少量的N2O。成功扩增了反硝化功能基因,norS,norB,norR,和nosz,进一步提出了从硝酸盐到氮的完整反硝化途径。此外,菌株表现出有效的聚集能力,自聚集指数和疏水性指数达到78.4和75.5%,分别。产生了大量的含蛋白质的EPS。此外,该菌株有效去除48.75、46.67、44.53和39.84%的Cr(VI),初始浓度为3、5、7和10mg/L,分别,从含氮的合成废水。它还可以将Cr(VI)还原为毒性较小的Cr(III)。FTIR测量和特征峰解卷积分析表明,在高Cr(VI)浓度的应力下,该应变具有强大的氢键结构,具有强大的分子间力。目前的结果证实,新型反硝化剂可以同时去除氮和铬,并在深度废水处理中具有潜在的应用,用于去除污水中的多种污染物。
The impact of high concentrations of heavy metals and the loss of functional microorganisms usually affect the nitrogen removal process in wastewater treatment systems. In the study, a unique auto-aggregating aerobic denitrifier (Pseudomonas stutzeri strain YC-34) was isolated with potential applications for Cr(VI) biosorption and reduction. The nitrogen removal efficiency and denitrification pathway of the strain were determined by measuring the concentration changes of inorganic nitrogen during the culture of the strain and amplifying key denitrification functional genes. The changes in auto-aggregation index, hydrophobicity index, and extracellular polymeric substances (EPS) characteristic index were used to evaluate the auto-aggregation capacity of the strain. Further studies on the biosorption ability and mechanism of cadmium in the process of denitrification were carried out. The changes in tolerance and adsorption index of cadmium were measured and the micro-characteristic changes on the cell surface were analyzed. The strain exhibited excellent denitrification ability, achieving 90.58% nitrogen removal efficiency with 54 mg/L nitrate-nitrogen as the initial nitrogen source and no accumulation of ammonia and nitrite-nitrogen. Thirty percentage of the initial nitrate-nitrogen was converted to N2, and only a small amount of N2O was produced. The successful amplification of the denitrification functional genes, norS, norB, norR, and nosZ, further suggested a complete denitrification pathway from nitrate to nitrogen. Furthermore, the strain showed efficient aggregation capacity, with the auto-aggregation and hydrophobicity indices reaching 78.4 and 75.5%, respectively. A large amount of protein-containing EPS was produced. In addition, the strain effectively removed 48.75, 46.67, 44.53, and 39.84% of Cr(VI) with the initial concentrations of 3, 5, 7, and 10 mg/L, respectively, from the nitrogen-containing synthetic wastewater. It also could reduce Cr(VI) to the less toxic Cr(III). FTIR measurements and characteristic peak deconvolution analysis demonstrated that the strain had a robust hydrogen-bonded structure with strong intermolecular forces under the stress of high Cr(VI) concentrations. The current results confirm that the novel denitrifier can simultaneously remove nitrogen and chromium and has potential applications in advanced wastewater treatment for the removal of multiple pollutants from sewage.