Optimization of the enzymatic elimination of flumequine by laccase-mediated system using response surface methodology

Abstract

Response surface methodology (RSM) was applied to optimize the removal of flumequine (FLU) from aqueous solution by laccase from Trametes versicolor. Box-Behnken design (BBD) with four variables namely pH, temperature, FLU initial concentration, and 2,2-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) concentration was used to optimize these factors. The results showed that the predicted values for FLU removal were close to the experimental values, and the R 2 (0.9967) indicated that the regression was able to give a good prediction of response for the FLU removal process in the studied range. Optimization of the factors levels was carried out in two approaches. At first, all factors were set in the studied range. The selected optimal conditions for the maximum removal of FLU (98.27%) were predicted as: temperature of 39.64˚C, pH of 4.06, FLU initial concentration of 90.74 mg L −1 , and ABTS concentration of 1.35 mM. Then, the optimization was carried out by minimizing the amount of ABTS, maximizing the FLU initial concentration, and maximizing the removal efficiency. The recommended optimum conditions are: temperature of 39.19˚C, pH value of 4.32, FLU initial concentration of 125 mg L −1 , and ABTS concentration of 0.28 mM with the percentage FLU removal of 77.76%.

Data on modeling of enzymatic elimination of Direct Red 81 using Response Surface Methodology

“…Laccase (EC 1.10.3.2, p-benzenediol:dioxygen oxidoreductases) from Trametes Versicolor (activity > 10 U mg −1 ) [1], [2], and ABTS, were purchased from Sigma Aldrich (St. Louis, MO, USA). The synthetic dye (DR81) was obtained from Alvan Sabet Co. (Tehran, Iran).…”

“…As described by Rekuć et al [1], [2], [3], monitoring the oxidation of 1 mL of 2 mM ABTS as a substrate (using UV–Vis spectrophotometer, λ max 420 nm) in a reaction mixture containing 0.1 M sodium citrate buffer (pH 4.5) and 1 mL of diluted enzyme sample at 40 °C, the laccase activity was calculated. One activity unit was defined as the amount of enzyme that oxidized 1 μmol of ABTS per min [1], [3].…”

“…The elimination studies were started by adding laccase according to the pH and ABTS (Table 3), solution volume of 5 mL, temperature 40 °C, and 150 rpm under dark for 30 min [2], [3].…”

Insights into laccase producing organisms, fermentation states, purification strategies, and biotechnological applications

“…They reported 67% of the toxic substrate was removed and the mutagenicity of the laccase‐treated product decreased significantly after 48 h incubation of AFB1 in the presence of laccase (30 U/mL) . Detoxification of endocrine‐disrupting compounds (EDCs) and different classes of pharmaceutical agents, such as antibiotics, analgesics, anticonvulsants, and sedatives, released from pharmaceutical company wastewaters by laccases from different organisms, has received increased attention during the last few decades . In most of these investigations, the laccase‐treated products showed lower toxicity compared with the initial compounds …”

“…The industrial production of laccases is the current impediment for application of laccases in chemical syntheses . This problem could be overcome by the overexpression of laccases from bacterial and fungal sources and the immobilization of purified laccases . Penicillin antibiotics, such as ampicillin, and cephalosporin derivatives, such as cefaclor, cefadroxil, cephalexin, and loracarbef (as nonlaccase substrates), have been combined with the laccase substrates of 2,5‐dihydroxybenzoic acid derivatives and methylcatechols by the purified laccase of the Trametes species to form novel antibiotic derivatives that inhibited methicillin‐resistant Staphylococcus aureus and vancomycin‐resistant enterococci .…”