Shi Yanke, Lin Hui, Ma Junwei, Zhu Rongrong, Sun Wanchun, Lin Xiaoyan, Zhang Jin, Zheng Huabao, Zhang Xin
College of Forest and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China; The Institute of Environment, Resources, Soil and Fertilizers, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
The Institute of Environment, Resources, Soil and Fertilizers, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
J Hazard Mater. 2021 Feb 5;403:123996. doi: 10.1016/j.jhazmat.2020.123996. Epub 2020 Sep 17.
Microbial degradation is an important option for combating antibiotic pollution. Arthrobacter nicotianae OTC-16 was isolated as a novel tetracycline-degrading bacterium, which could degrade oxytetracycline/tetracycline (OTC/TET). Toxicity assessment indicated that this bacterium effectively converted OTC into byproducts with less toxicity to bacterial and algal indicators. Six degradation products of OTC were tentatively identified, and a potential biotransformation pathway was proposed that includes decarbonylation, reduction, and dehydration. Bioaugmentation of TC removal with this bacterium was further studied in various matrices. In aqueous media, strain OTC-16 accelerated OTC removal over a temperature range of 20-35 ℃, pH range of 6.0-9.0, and OTC concentration range of 25-150 mg L. The strain also facilitated the decrease of OTC and TET concentrations in both swine and chicken manures, with a maximum decrease of 91.54%, and increased the degradation of OTC in soils by 8.22-45.45%. A unique advantage of this bacterium in promoting OTC degradation in alkaline environments was demonstrated, where it successfully competed with the indigenous microbiota and largely decreased the relative abundances of the studied tetracycline resistance genes (tetB and tetW) in soil. This work offers a better understanding of the antibiotic bioaugmentation and new microbial sources.
微生物降解是对抗抗生素污染的重要选择。烟草节杆菌OTC-16被分离出来作为一种新型的四环素降解菌，它能够降解土霉素/四环素（OTC/TET）。毒性评估表明，这种细菌有效地将OTC转化为对细菌和藻类指标毒性较小的副产物。初步鉴定出OTC的六种降解产物，并提出了一条潜在的生物转化途径，包括脱羰、还原和脱水。进一步研究了用这种细菌进行生物强化去除四环素的情况，研究了各种基质。在水介质中，OTC-16菌株在20-35℃的温度范围、6.0-9.0的pH范围以及25-150mg/L的OTC浓度范围内加速了OTC的去除。该菌株还促进了猪粪和鸡粪中OTC和TET浓度的降低，最大降幅为91.54%，并使土壤中OTC的降解率提高了8.22-45.45%。证明了这种细菌在促进碱性环境中OTC降解方面的独特优势，它成功地与本地微生物群竞争，并在很大程度上降低了土壤中所研究的四环素抗性基因（tetB和tetW）的相对丰度。这项工作有助于更好地理解抗生素生物强化和新的微生物来源。
