Faculty of Chemistry and Environmental Science, Guangdong Ocean University, Zhanjiang 524088, PR China; Shenzhen Research Institute of Guangdong Ocean University, Shenzhen 518108, PR China.
College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang 524088, PR China.
J Hazard Mater. 2021 Jun 15;412:125212. doi: 10.1016/j.jhazmat.2021.125212. Epub 2021 Jan 23.
This study explored the change of tetracycline degradation efficiency, metabolic pathway, soil physiochemical properties and degraders in vermiremediation by two earthworm species of epigeic Eisenia fetida and endogeic Amynthas robustus. We found a significant acceleration of tetracycline degradation in both earthworm treatments, and 4-epitetracycline dehydration pathway was remarkably enhanced only by vermiremediation. Tetracycline degraders from soils, earthworm intestines and casts were different. Ralstonia and Sphingomonas were potential tetracycline degraders in soils and metabolized tetracycline through direct dehydration pathway. Degraders in earthworm casts (Comamonas, Acinetobacter and Stenotrophomonas) and intestines (Pseudomonas and Arthrobacter) dehydrated 4-epitetracycline into 4-epianhydrotetracycline. More bacterial lineages resisting tetracycline were found in earthworm treatments, indicating the adaptation of soil and intestinal flora under tetracycline pressure. Earthworm amendment primarily enhanced tetracycline degradation by neutralizing soil pH and consuming organic matters, stimulating both direct dehydration and epimerization-dehydration pathways. Our findings proved that vermicomposting with earthworms is effective to alter soil microenvironment and accelerate tetracycline degradation, behaving as a potential approach in soil remediation at tetracycline contaminated sites.
本研究探讨了两种土壤蚯蚓（表栖的赤子爱胜蚓和内栖的威廉环毛蚓）在蚯蚓修复过程中对四环素降解效率、代谢途径、土壤理化性质和降解菌的影响。我们发现，两种蚯蚓处理均显著加速了四环素的降解，而只有蚯蚓修复显著增强了 4-差向脱水四环素的形成途径。土壤、蚯蚓肠道和蚓粪中的四环素降解菌不同。土壤中的拉氏不动杆菌和鞘氨醇单胞菌可能是四环素的降解菌，通过直接脱水途径代谢四环素。蚓粪中的贪噬菌、不动杆菌和寡养单胞菌和肠道中的假单胞菌和节杆菌将 4-差向脱水四环素转化为 4-差向脱水四环素。在蚯蚓处理中发现了更多抵抗四环素的细菌类群，表明土壤和肠道菌群在四环素压力下适应。蚯蚓添加物主要通过中和土壤 pH 值和消耗有机物来增强四环素的降解，刺激直接脱水和差向异构化-脱水途径。本研究结果证明，利用蚯蚓进行堆肥处理可以有效地改变土壤微环境，加速四环素的降解，是四环素污染场地土壤修复的一种潜在方法。
