School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, PR China.
School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, PR China; Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, 571158, China.
Chemosphere. 2021 Apr;269:128705. doi: 10.1016/j.chemosphere.2020.128705. Epub 2020 Oct 22.
Enzyme catalyzed coupling with redox mediators are considered as great interesting and viable technologies to transform antibiotics. This work demonstrated the horseradish peroxidase (HRP) was effective in transforming sulfadiazine (SDZ) transformation coupled with 1-hydroxybenzotriazole (HBT) at varying conditions. The removal of SDZ was independent of Na and its ionic strength, but Ca could enhance transformation efficiency by increasing the enzyme activity of HRP. The presence of humic acid (HA) and polystyrene (PS) microplastics showed inhibition on the transformation of SDZ, and the transformation rate constants (k) decreased with the concentration of HA and PS particles increased. These primarily attributed to covalent coupling and electrostatic interaction between SDZ and HA, SDZ and PS, respectively, which reduced the concentration of free SDZ in the reaction solution. The presence of cation recovered the inhibition of SDZ transformation by HA and PS particles, which ascribed to compete between cation and SDZ. The divalent cations (Ca) showed more substantial competitiveness than mono (Na) due to more carried charge. Eight possible transformation products were identified, and potential SDZ transformation pathways were proposed, which include δ-cleavage, γ-cleavage, carbonylation, hydroxylation, SO extrusion and SO extrusion. In addition, HA and PS particles couldn't affect the transformation pathways of SDZ. These findings provide novel understandings of the transformation and the fate of antibiotics in the natural environment by HRP coupled with redox mediators.
酶促偶联与氧化还原介体被认为是将抗生素转化为具有重要意义和可行性的技术。本研究表明辣根过氧化物酶（HRP）在不同条件下与 1-羟基苯并三唑（HBT）偶联时，可有效转化磺胺嘧啶（SDZ）。SDZ 的去除与 Na 及其离子强度无关，但 Ca 可以通过增加 HRP 的酶活性来提高转化效率。腐殖酸（HA）和聚苯乙烯（PS）微塑料的存在对 SDZ 的转化表现出抑制作用，转化速率常数（k）随着 HA 和 PS 颗粒浓度的增加而降低。这主要归因于 SDZ 与 HA、SDZ 与 PS 之间的共价偶联和静电相互作用，分别降低了反应溶液中游离 SDZ 的浓度。阳离子的存在恢复了 HA 和 PS 颗粒对 SDZ 转化的抑制作用，这归因于阳离子与 SDZ 之间的竞争。由于携带更多的电荷，二价阳离子（Ca）比单价阳离子（Na）表现出更强的竞争力。鉴定出了 8 种可能的转化产物，并提出了潜在的 SDZ 转化途径，包括 δ-断裂、γ-断裂、羰基化、羟化、SO 脱除和 SO 脱除。此外，HA 和 PS 颗粒不会影响 SDZ 的转化途径。这些发现为 HRP 与氧化还原介体偶联在自然环境中抗生素的转化和归宿提供了新的认识。
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