College of Life Sciences, Northeast Forestry University, Harbin, 150040, China.
College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, China.
Environ Res. 2023 Jan 1;216(Pt 3):114690. doi: 10.1016/j.envres.2022.114690. Epub 2022 Nov 5.
The presence of antibiotics in the environment causes increasing attention due to their potential risks to ecosystems and public health. Laccases are versatile oxidases capable of degrading various organic contaminants including pharmaceuticals. However, the performance of bacterial laccases on tetracycline antibiotics (TCs) degradation is seldom investigated. In this work, a bacterial laccase from Bacillus amyloliquefaciens was immobilized as laccase-inorganic hybrid nanoflowers (Lac-hNFs) by a facile and rapid method. The immobilized laccase was employed to remove different TCs including tigecycline, which is a third-generation TC that its degradation by laccase has not been reported. Lac-hNFs were synthesized by sonication-mediated self-assembly of laccase and copper ions in 5 min at room temperature. About 95% of laccase could be encapsulated in the nanoflowers, and the obtained Lac-hNFs exhibited great enhancement in stability under harsh conditions. The immobilized laccase showed a half-life of 11.7 h at 60 °C, which was about 1.4-fold higher than that of the free enzyme. Meanwhile, Lac-hNFs retained 81% of the initial activity after incubation at 25 °C for 10 days. The laccase in combination with acetosyringone could efficiently decompose tetracycline, doxycycline, and tigecycline. More than 79% of the three TCs were transformed in 1 h. Compared with the free enzyme, Lac-hNFs demonstrated higher capacity in the removal of TCs. Furthermore, Lac-hNFs remained their high degradation capacity after five cycles of reuse. Bacterial growth inhibition test revealed that most of the toxicity of TCs was eliminated after Lac-hNFs treatment. The main transformation products were identified by LC-MS, and the possible degradation pathways were proposed. The interaction mechanism between laccase and TCs was also analyzed using molecular docking. This work provides an efficient way to remove toxic organic pollutants.
由于抗生素对生态系统和公共健康的潜在风险，其在环境中的存在引起了越来越多的关注。漆酶是一种多功能氧化酶，能够降解包括药物在内的各种有机污染物。然而，细菌漆酶对四环素抗生素（TCs）降解的性能很少被研究。在这项工作中，通过一种简便快速的方法，将解淀粉芽孢杆菌中的细菌漆酶固定化为漆酶-无机杂化纳米花（Lac-hNFs）。固定化漆酶被用于去除不同的 TCs，包括未报道过其可被漆酶降解的第三代 TC 替加环素。Lac-hNFs 通过在室温下超声介导的漆酶和铜离子自组装 5 分钟合成。约 95%的漆酶可以被封装在纳米花中，并且所得到的 Lac-hNFs 在恶劣条件下表现出了极大的稳定性增强。固定化漆酶在 60°C 下半衰期为 11.7 小时，比游离酶高 1.4 倍。同时，Lac-hNFs 在 25°C 下孵育 10 天后仍保留初始活性的 81%。漆酶与乙酰丁香酮结合可以有效地分解四环素、强力霉素和替加环素。三种 TCs 中有超过 79%在 1 小时内转化。与游离酶相比，Lac-hNFs 在去除 TCs 方面表现出更高的能力。此外，Lac-hNFs 在重复使用五次后仍保持其高降解能力。细菌生长抑制试验表明，经过 Lac-hNFs 处理后，大部分 TCs 的毒性被消除。通过 LC-MS 鉴定了主要的转化产物，并提出了可能的降解途径。还使用分子对接分析了漆酶和 TCs 之间的相互作用机制。这项工作为去除有毒有机污染物提供了一种有效的方法。
