Zhang Yancheng, Li Jing, Pang Yu, Shu Yilin, Liu Shu, Sang Pengcheng, Sun Xiaohui, Liu Jiexiu, Yang Yanfang, Chen Minglin, Hong Pei
College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China.
College of Life Sciences, School of Ecology and Environment, Collaborative Innovation Center of Recovery and Reconstruction of Degraded Ecosystem in Wanjiang Basin Co-founded By Anhui Province and Ministry of Education, Anhui Normal University, Wuhu, 241002, China.
Environ Res. 2023 Oct 15;235:116602. doi: 10.1016/j.envres.2023.116602. Epub 2023 Jul 8.
Finding effective methods for simultaneous removal of eutrophic nutrients and heavy metals has attracted increasing concerns for the environmental remediation. Herein, a novel auto-aggregating aerobic denitrifying strain (Aeromonas veronii YL-41) was isolated with capacities for copper tolerance and biosorption. The denitrification efficiency and nitrogen removal pathway of the strain were investigated by nitrogen balance analysis and amplification of key denitrification functional genes. Moreover, the changes in the auto-aggregation properties of the strain caused by extracellular polymeric substances (EPS) production were focused on. The biosorption capacity and mechanisms of copper tolerance during denitrification were further explored by measuring changes in copper tolerance and adsorption indices, as well as by variations in extracellular functional groups. The strain showed extremely strong total nitrogen removal ability, with 67.5%, 82.08% and 78.48% of total nitrogen removal when NH-N, NO-N, and NO-N were used as the only initial nitrogen source, respectively. The successful amplification of napA, nirK, norR, and nosZ genes further demonstrated that the strain accomplished nitrate removal through a complete aerobic denitrification pathway. The production of protein-rich EPS of up to 23.31 mg/g and an auto-aggregation index of up to 76.42% may confer a strong biofilm-forming potential to the strain. Under the stress of 20 mg/L copper ions, the removal of nitrate-nitrogen was still as high as 71.4%. In addition, the strain could achieve an efficient removal of 96.9% of copper ions at an initial concentration of 80 mg/L. Scanning electron microscopy and deconvolution analysis of characteristic peaks confirmed that the strains encapsulate heavy metals by secreting EPS and, meanwhile, form strong hydrogen bonding structures to enhance intermolecular forces to resist copper ion stress. This study provides an innovative and effective biological approach for the synergistic bioaugmentation removal of eutrophic substances and heavy metals from aquatic environments.
寻找同时去除富营养化养分和重金属的有效方法已引起环境修复领域越来越多的关注。在此，分离出一种新型的自聚集好氧反硝化菌株（维罗纳气单胞菌YL-41），其具有耐铜和生物吸附能力。通过氮平衡分析和关键反硝化功能基因的扩增，研究了该菌株的反硝化效率和氮去除途径。此外，还关注了由胞外聚合物（EPS）产生引起的菌株自聚集特性的变化。通过测量耐铜性和吸附指数的变化以及胞外官能团的变化，进一步探讨了反硝化过程中菌株的生物吸附能力和耐铜机制。该菌株表现出极强的总氮去除能力，当分别以NH-N、NO-N和NO-N作为唯一初始氮源时，总氮去除率分别为67.5%、82.08%和78.48%。napA、nirK、norR和nosZ基因的成功扩增进一步证明该菌株通过完整的好氧反硝化途径实现了硝酸盐的去除。高达23.31 mg/g的富含蛋白质的EPS的产生和高达76.42%的自聚集指数可能赋予该菌株强大的生物膜形成潜力。在20 mg/L铜离子的胁迫下，硝酸盐氮的去除率仍高达71.4%。此外，该菌株在初始浓度为80 mg/L时能够高效去除96.9%的铜离子。扫描电子显微镜和特征峰的去卷积分析证实，该菌株通过分泌EPS包裹重金属，同时形成强大的氢键结构以增强分子间力来抵抗铜离子胁迫。本研究为从水环境中协同生物强化去除富营养化物质和重金属提供了一种创新且有效的生物学方法。
