AUTHOR=Maldonado Ingrid , Vega Quispe Anyela Pierina , Merma Chacca Donald , Zirena Vilca Franz 

TITLE=Optimization of the elimination of antibiotics by Lemna gibba and Azolla filiculoides using response surface methodology (RSM)

JOURNAL=Frontiers in Environmental Science

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2022.940971

DOI=10.3389/fenvs.2022.940971

ISSN=2296-665X

ABSTRACT=<p>Antibiotic residues have been found in environmental samples, such as water, soil, and even food, and usually come from wastewater, presenting environmental and human health risks. This study aimed to improve the elimination of the antibiotics tetracycline (Tet) and chloramphenicol (Chlor) by modifying three factors: contact time (3–7 days), plant biomass (10–14 g), and antibiotic concentration (5–15 mg/L Tet and 10–20 mg/L Chlor). An approach that optimizes time and resources, response surface methodology (RSM), was applied with a Box–Behnken design (BBD) to two plant species (<italic>L. gibba</italic> and <italic>A. filiculoides</italic>), i.e., one experimental design was used for each species. Antibiotic residues in water and plant samples were analyzed by liquid chromatography. The optimal conditions for Tet removal were 6.04 d, 11.4 g, and 13.4 mg/L with <italic>Lemna</italic> and 6.3 d, 11.9 g, and 14.7 mg/L with <italic>Azolla</italic>; the optimal conditions for Chlor removal were 7.8 d, 13.6 g, and 10.2 mg/L with <italic>Lemna</italic> and 4.6 d, 12.3 g, and 8.7 mg/L with <italic>Azolla</italic>. The results showed that the removal efficiency of antibiotics increased depending on the species used, reaching a maximum of up to 100%. Tet was better removed than Chlor, reaching maximum removal values of 100% and 84% with <italic>Azolla</italic> and <italic>Lemna</italic>, respectively. Chlor removal reached 70% and 64% with <italic>Azolla</italic> and <italic>Lemna</italic>, respectively. The mean bioconcentration factors (BCFs) of Tet were 2.9% in <italic>Lemna</italic> and 4.9% in <italic>Azolla</italic>, and the BCFs for Chlor were 38.1% in <italic>Lemna</italic> and 37.8% in <italic>Azolla</italic>. Thus, in general, better results were obtained with <italic>Azolla</italic>. In summary, the results demonstrate that this design and the selected plants contribute to the removal of antibiotics, presenting a sustainable and recommended alternative for the treatment of wastewater contaminated with antibiotic residues.</p>