The global presence of antibiotics in the environment has created concerns about the emergence of antibiotic resistance bacteria and potential hazard to humans and the ecosystem. This work aims to study the removal of levofloxacin, a new generation fluoroquinolone antibiotic from aqueous solutions by enzyme mediated oxidation process and optimization of the conditions thereof by response surface methodology (RSM) using Box-Behnken design (BBD). For this study, experiments were conducted to analyze the effect of independent variables namely, pH, temperature, mediator concentration and antibiotic concentration on the degradation percentage of levofloxacin antibiotic using laccase enzyme derived from Trametes versicolor. The residual levofloxacin concentration was determined using high performance liquid chromatography (HPLC). On applying the quadratic regression analysis, among the main parameters, it was found that the percentage degradation was significantly affected by all the four variables. The predicted values for percentage degradation of levofloxacin were close to the experimental values obtained and the R² (0.95) indicated that the regression was able to give a good prediction of response for the percentage degradation of levofloxacin in the studied range. The optimal conditions for the maximum degradation (99.9%) as predicted by the BBD were: temperature of 37 °C, pH of 4.5, mediator concentration of 0.1 mM and levofloxacin concentration of 5 μg mL⁻¹. The findings of the study were further extended to study the effect of partially purified enzymes isolated from Pleurotus eryngii, Pleurotus florida and Pleurotus sajor caju on the degradation of levofloxacin at concentrations ranging from as low as 0.1 to as high as 50 µg mL⁻¹ in synthetic wastewater utilizing the optimized conditions generated by BBD. A maximum degradation of 88.8% was achieved with the partially purified enzyme isolated from Pleurotus eryngii at 1 µg mL⁻¹ levofloxacin concentration which was at par with the commercial laccase which showed 89% degradation in synthetic wastewater at the optimized conditions. The biodegradation studies were conducted using only 2 units of laccase. Thus, the expensive commercial laccase can be effectively replaced by crude laccase isolated from indigenous macrofungi such as P. eryngii, P. florida and P. sajor caju as a cost effective alternative to degrade levofloxacin present in contaminated wastewater using as low as 2 units of enzyme for a 72 h treatment period.

环境中抗生素的全球存在引起了人们对抗生素抗性细菌的出现以及对人类和生态系统的潜在危害的担忧。本工作旨在研究通过酶介导氧化过程从水溶液中去除新一代氟喹诺酮类抗生素左氧氟沙星，并使用 Box-Behnken 设计 (BBD) 通过响应面法 (RSM) 优化其条件。对于这项研究，进行了实验，以分析使用Trametes versicolor的漆酶对pH，温度，介体浓度和抗生素浓度等独立变量对左氧氟沙星抗生素降解百分率的影响。. 残留的左氧氟沙星浓度使用高效液相色谱法（HPLC）测定。在应用二次回归分析时，在主要参数中，发现退化百分比受所有四个变量的显着影响。左氧氟沙星降解百分比的预测值与获得的实验值接近，R ² (0.95) 表明回归能够很好地预测所研究范围内左氧氟沙星降解百分比的响应。BBD 预测的最大降解 (99.9%) 的最佳条件是：温度为 37 °C，pH 为 4.5，介质浓度为 0.1 mM，左氧氟沙星浓度为 5 μg mL ^-1. 该研究的结果被进一步扩展以研究部分纯化的酶分离自的效果杏鲍菇，佛罗里达侧耳和侧耳sajor caju浓度范围从低至0.1至左氧氟沙星的降解高达50微克毫升^-1在利用 BBD 产生的优化条件的合成废水。从杏鲍菇中分离出的部分纯化酶以 1 µg mL ^{-1 的}浓度实现了 88.8% 的最大降解左氧氟沙星浓度与商业漆酶相当，在优化条件下，在合成废水中降解率为 89%。仅使用2个单位的漆酶进行了生物降解研究。因此，昂贵的商业漆酶可以有效地被从本地大型真菌（例如P. eryngii、P. florida和P. sajor caju ）中分离出来的粗漆酶替代，作为一种成本有效的替代品，使用低至 2 个单位的酶处理 72 小时。