Biodegradation of sulfametoxydiazine by Alcaligenes aquatillis FA: Performance, degradation pathways, and mechanisms
Biodegradation of sulfametoxydiazine by Alcaligenes aquatillis FA: Performance, degradation pathways, and mechanisms
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DOI：
10.1016/j.jhazmat.2023.131186
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发表时间：
2023-03-20
影响因子：
13.6
通讯作者：
Lin, Hui
中科院分区：
文献类型：
--
作者：
Du, Yuqian;Cheng, Qilu;Lin, Hui
本研究报道了一种新的细菌菌株Alcaligenes aquatilis FA的分离和表征，具有降解磺胺甲氧嘧啶（SMD）的能力，磺胺甲氧嘧啶是一种常用的磺胺类抗生素（SA）在畜禽生产中。研究了FA对SMD的生物降解动力学、途径和基因组背景。结果表明，菌株FA对SMD具有很强的降解专一性，不能有效降解其异构体磺胺间甲氧嘧啶。SMD的生物降解符合一级动力学模型，速率常数为27.39 mg·L-1·d-1，半衰期为5.98 d。通过对SMD生物降解副产物的鉴定以及采用生态结构-活性关系（ECOSAR）模型和生物指示剂进行生物毒性评价，提出了SMD的生物降解途径和解毒过程。在SMD的生物降解过程中，新的降解酶，如二甲基砜单加氧酶，4-羧基粘康酸内酯脱羧酶，和1，4-苯醌还原酶的参与被推断。菌株FA中存在sul 2和dfrA基因，它们在其细胞中组成型表达，表明菌株采用多种机制来抵抗SMD。这项研究为磺胺类抗生素（SA）的生物降解提供了新的见解，因为它是第一个描述SMD降解细菌及其遗传信息。
This study reports the isolation and characterization of a novel bacterial strain Alcaligenes aquatillis FA with the ability to degrade sulfametoxydiazine (SMD), a commonly used sulfonamide antibiotic (SA) in livestock and poultry production. The biodegradation kinetics, pathways, and genomic background of SMD by FA were investigated. The results showed that strain FA had high specificity to degrade SMD, and was unable to effectively degrade its isomer, sulfamonomethoxine. The SMD biodegradation followed a first-order kinetic model with a rate constant of 27.39 mg center dot L-1 center dot day(-1) and a half-life of 5.98 days. The biodegradation pathways and detoxification processes of SMD were proposed based on the identification of its biodegradation byproducts and the biotoxicity assessment using both the ecological structure-activity relationship (ECOSAR) model and biological indicator. The involvement of novel degrading enzymes, such as dimethyllsulfone monooxygenase, 4-carboxymuconolactone decarboxylase, and 1,4-benzoquinone reductase, was inferred in the SMD biodegradation process. The presence of sul2 and dfrA genes in strain FA, which were constitutively expressed in its cells, suggests that multiple mechanisms were employed by the strain to resist SMD. This study provides new insights into the biodegradation of sulfonamide antibiotics (SAs) as it is the first to describe an SMD-degrading bacterium and its genetic information.