Elimination of Isoxazolyl-Penicillins antibiotics in waters by the ligninolytic native Colombian strain Leptosphaerulina sp considerations on biodegradation process and antimicrobial activity removal

In this work, Leptosphaerulina sp. (a Colombian native fungus) significantly removed three lsoxazolyl-Penicillin antibiotics (IP): oxacillin (OXA, 16000 mu g L-1), cloxacillin (CLX, 17500 mu g L-1) and dicloxacillin (DCX, 19000 fig L-1) from water. The biological treatment was perfomied at pH 5.6, 28 degrees C, and 160 rpm for 15 days. The biotransformation process and lack of toxicity of the final solutions (antibacterial activity (AA) and cytotoxicity) were tested. The role of enzymes in IP removal was analysed through in vitro studies with enzymatic extracts (crude and pre-puiified) from Leptosphaenitina sp., commercial enzymes and enzymatic inhibitors. Furthermore, the applicability of mycoremaliation process to a complex matrix (simulated hospital wastewater) was evaluated. IP were considerably abated by the fungus, OXA was the fastest degraded (day 6), followed by CLX (day 7) and DCX (day 8). Antibiotics biodegradation was associated to lactase and versatile peroxidase action. Assays using commercial enzymes (i.e. lactase from Trametes versicolor and horseradish peroxidase) and inhibitors (EDTA, NaCI, sodium acetate, manganese (11) ions) confirmed the significant role of enzymatic transformation. Whereas, biomass sorption was not an important process in the antibiotics elimination. Evaluation of AA against Staphylococars aureus ATCC 6538 revealed that Leptosphaenrlina sp. also eliminated the M. In addition, the cytotoxicity assay (MTT) on the HepG2 cell line demonstrated that the IP final solutions were non-toxic. Finally, Leptosphaerulina sp. eliminated OXA and its AA from synthetic hospital wastewater at 6 days. All these results evidenced the potential of Leptosphaerulina sp. mycoremediation as a novel environmentally friendly process for the removal of IP from aqueous systems. (C) 2018 Elsevier B.V. All rights reserved.