Degradación de residuos de oxitetraciclina en leche a través de pre-tratamientos y uso de lacasas, para mitigar la contaminación del suelo y agua.

Abstract

The objective of this work was to analyze the degradation of oxytetracycline residues in milk using the laccase enzyme and performing pretreatments. Milk samples were prepared with 200 µM of oxytetracycline, which were thermally pretreated, drained to obtain the serum, skimmed or without treatment. These in turn were subdivided into 3 subgroups, each of which were inoculated with 0,1 mg L-1; 0,2 mg L-1 or 0,3 mg L-1 of laccase. Before inoculation with laccase, control samples were taken and after addition of the enzyme, samples were taken every hour for 6 hours. An extraction of the antibiotic was performed to quantify its presence in the milk or serum samples through high performance liquid chromatography. A repeated measures ANOVA was performed and the differences between groups was determined with the Bonferroni test. The positive effect of the degradation of oxytetracycline in milk or serum was due to the action of laccase in all its concentrations or by the pretreatment of drainage without addition of laccase, achieving 75% removal of the antibiotic. It is recommended to use acidification to obtain the serum, which has levels of oxytetracycline low enough to reuse it, instead of discarding it in the soil or water.