title: Degradation of tetracycline by immobilized laccase and the proposed transformation pathway.
abstract: Magnetic cross-linked enzyme aggregates (M-CLEAs) were prepared for Cerrena laccase and used in antibiotic treatment. Of the seven antibiotics examined in this study, Cerrena laccase M-CLEAs were most effective in degradation of tetracycline (TC) and oxytetracycline (OTC), followed by ampicillin, sulfamethoxazole and erythromycin. The redox mediator ABTS was not able to improve efficiencies of degradation of TC and OTC. Cerrena laccase at 40U/mL eliminated 100μg/mL TC at pH 6 and 25°C in 48h in the absence of a redox mediator, with over 80% degradation occurring within the first 12h. Laccase treatment also significantly suppressed the antimicrobial activity of TC and OTC. Three TC transformation products, the levels of which initially increased and subsequently decreased during laccase treatment were identified by using LC-TOF MS. A mechanism of laccase-mediated TC oxidation was proposed based on the identified intermediates.
authors: Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou University, Fujian 350116, China. Electronic address: T09136@fzu.edu.cn.
authors: Jie
authors: J
authors: Yang
authors: Technical Center, Fujian Entry-Exit Inspection and Quarantine Bureau, Fuzhou, Fujian 350001, China.
authors: Yonghui
authors: Y
authors: Lin
authors: Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou University, Fujian 350116, China.
authors: Xiaodan
authors: X
authors: Yang
authors: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors: Tzi Bun
authors: TB
authors: Ng
authors: Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou University, Fujian 350116, China.
authors: Xiuyun
authors: X
authors: Ye
authors: Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou University, Fujian 350116, China. Electronic address: ljuan@fzu.edu.cn.
authors: Juan
authors: J
authors: Lin
mesh_terms: D003432:Cross-Linking Reagents; D005976:Glutaral; D042845:Laccase / Q000378:metabolism*; D060328:Magnetic Phenomena; D011124:Polyporaceae; D013752:Tetracycline / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D003432:Cross-Linking Reagents; D014874:Water Pollutants, Chemical; D042845:Laccase; D013752:Tetracycline; D005976:Glutaral
keywords: Antimicrobial activity; Laccase; M-CLEAs; Tetracycline; Transformation products