Guadie Awoke, Han Jing-Long, Liu Wenzong, Ding Yang-Cheng, Minale Mengist, Ajibade Fidelis O, Zhai Siyuan, Wang Hong-Cheng, Cheng Haoyi, Ren Nanqi, Wang Aijie
Key Laboratory of Environmental Biotechnology Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Department of Biology, College of Natural Sciences, Arba Minch University, Arba Minch 21, Ethiopia.
School of Civil & Environmental Engineering, Harbin Institute of Technology, Shenzhen, 518055, China.
J Environ Manage. 2021 Jun 1;287:112297. doi: 10.1016/j.jenvman.2021.112297. Epub 2021 Mar 8.
Pyridine contamination poses a significant threat to human and environmental health. Due to the presence of nitrogen atom in the pyridine ring, the pi bond electrons are attracted toward it and make difficult for pyridine treatment with biological and chemical methods. In this study, coupling Fenton treatment with different biological process was designed to enhance pyridine biotransformation and further mineralization. After Fenton oxidation process optimized, pretreated pyridine was evaluated under three biological (anaerobic, aerobic and microaerobic) operating conditions. Under optimum Fenton oxidation, pyridine (30-75%) and TOC (5-25%) removal efficiencies were poor. Biological process alone also showed insignificant removal efficiency, particularly anaerobic (pyridine = 8.2%; TOC = 5.3%) culturing condition. However, combining Fenton pretreatment with biological process increased pyridine (93-99%) and TOC (87-93%) removals, suggesting that hydroxyl radical generated during Fenton oxidation enhanced pyridine hydroxylation and further mineralization in the biological (aerobic > microaerobic > anaerobic) process. Intermediates were analyzed with UPLC-MS and showed presence of maleic acid, pyruvic acid, glutaric dialdehyde, succinic semialdehyde and 4-formylamino-butyric acid. High-throughput sequencing analysis also indicated that Proteobacteria (35-43%) followed by Chloroflexi (10.6-24.3%) and Acidobacteria (8.0-29%) were the dominant phyla detected in the three biological treatment conditions. Co-existence of dominant genera under aerobic/microaerobic (Nitrospira > Dokdonella > Caldilinea) and anaerobic (Nitrospira > Caldilinea > Longilinea) systems most probably play significant role in biotransformation of pyridine and its intermediate products. Overall, integrating Fenton pretreatment with different biological process is a promising technology for pyridine treatment, especially the combined system enhanced anaerobic (>10 times) microbial pyridine biotransformation activity.
吡啶污染对人类健康和环境构成重大威胁。由于吡啶环中存在氮原子，π键电子被吸引向氮原子，这使得用生物和化学方法处理吡啶变得困难。在本研究中，设计了将芬顿处理与不同生物过程相结合的方法，以增强吡啶的生物转化及进一步矿化。在优化芬顿氧化过程后，在三种生物（厌氧、好氧和微氧）操作条件下对预处理后的吡啶进行了评估。在最佳芬顿氧化条件下，吡啶（30 - 75%）和总有机碳（TOC，5 - 25%）的去除效率较低。单独的生物过程去除效率也不显著，特别是在厌氧培养条件下（吡啶 = 8.2%；TOC = 5.3%）。然而，将芬顿预处理与生物过程相结合可提高吡啶（93 - 99%）和TOC（87 - 93%）的去除率，这表明芬顿氧化过程中产生的羟基自由基增强了吡啶的羟基化作用，并在生物（好氧 > 微氧 > 厌氧）过程中进一步促进了矿化。使用超高效液相色谱 - 质谱联用仪（UPLC - MS）对中间产物进行分析，结果显示存在马来酸、丙酮酸、戊二醛、琥珀酸半醛和4 - 甲酰氨基丁酸。高通量测序分析还表明，在三种生物处理条件下检测到的主要门类为变形菌门（35 - 43%），其次是绿弯菌门（10.6 - 24.3%）和酸杆菌门（8.0 - 29%）。在好氧/微氧（硝化螺菌属 > 多尔氏菌属 > 嗜热放线菌属）和厌氧（硝化螺菌属 > 嗜热放线菌属 > 长丝菌属）系统中优势属的共存很可能在吡啶及其中间产物的生物转化中发挥重要作用。总体而言，将芬顿预处理与不同生物过程相结合是一种很有前景的吡啶处理技术，特别是该组合系统增强了厌氧条件下（超过10倍）微生物对吡啶的生物转化活性。
