Elimination of tetracyclines in seawater by laccase-mediator system

Laccases as Effective Tools in the Removal of Pharmaceutical Products from Aquatic Systems

“…In the case of tetracycline in the presence of laccase from B. amyloliquefaciens, the opening of the aromatic ring was observed in two of the three putative pathways, preceded by epimerization, demethylation, deamination, dehydrogenation, and hydroxylation in the second putative pathway or demethylation and dehydrogenation, dehydroxylation in the third pathway (Figure 6) [72]. The same reactions, leading to the formation of degradation products with a smaller molecular size, have also been observed for tetracycline degraded by fungal laccase [74] and other tetracycline antibiotics such as doxycycline and tigecycline [72]. The loss of the antibiotic effect of tetracycline was also confirmed by ecotoxicity assays determined via the incubation of degradation products with B. subtilis and E. coli bacteria [69].…”

“…Tetracycline antibiotics as broad-spectrum antibiotics are widely used to treat human and animal diseases, making them the second most widely used antibiotics in the world [73]. Laccase produced by bacteria and expressed in E. coli, as well as laccase from Myceliophthora thermophila, expressed in Aspergillus sp., have been tested [72,74]. Laccase from Bacillus amyloliquefaciens, expressed in E. coli, was able to efficiently remove tetracycline antibiotics such as tetracycline, doxycycline, and tigecycline with the efficiency of 86.1, 96.5 and 81.0%, respectively [72].…”

“…Tetracycline was biotransformed to a level below the detection limit of the HPLC analysis after a 2-h catalyzed reaction with laccase of B. subtilis, expressed in E. coli [69]. Laccase from M. thermophila exhibited the complete removal of tetracycline using SYR as a redox mediator even in salt water [74]. The authors proposed a putative mechanism of tetracycline biotransformation with two possible pathways, both leading to the opening of the tetracycline ring to form small acid molecules, resulting in a loss of antibiotic activity.…”

Evaluation of Antibiotic Biodegradation by a Versatile and Highly Active Recombinant Laccase from the Thermoalkaliphilic Bacterium Bacillus sp. FNT

“…Subsequently, the hydroxyl at C6 was removed to form TC5, which could be further decomposed to produce TC6, TC7, and TC8 [ 89 ]. Similar reactions leading to the formation of degradation products with a smaller molecular size have been reported for biodegradation of TC by fungal laccases, [ 48 , 82 , 87 ].…”

“…Molecular docking approaches have been widely used for estimating the binding affinity between enzymes and diverse substrates, thereby facilitating the comprehension of protein–ligand interaction mechanisms. Previous investigations employing molecular docking have explored the binding of laccase enzymes with different antibiotic families, including β-lactams [ 8 ], tetracyclines [ 48 ], and fluoroquinolone [ 49 ] groups, which have provided insights into the binding modes, binding free energies, and key residues involved in the interactions between laccase enzymes and antibiotics.…”