Xu KZ, Ma H, Wang YJ, Cai YJ, Liao XR, Guan ZB. Extracellular expression of mutant CotA-laccase SF in Escherichia coli and its degradation of malachite green.
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020;
193:110335. [PMID:
32088549 DOI:
10.1016/j.ecoenv.2020.110335]
[Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 02/10/2020] [Accepted: 02/13/2020] [Indexed: 06/10/2023]
Abstract
In this study, mutant CotA-laccase SF was successfully expressed in Escherichia coli by co-expression with phospholipase C. The optimized extracellular expression of CotA-laccase SF was 1257.22 U/L. Extracellularly expressed CotA-laccase SF exhibits enzymatic properties similar to intracellular CotA-laccase SF. CotA-laccase SF could decolorize malachite green (MG) under neutral and alkaline conditions. The Km and kcat values of CotA-laccase SF to MG were 39.6 mM and 18.36 s-1. LC-MS analysis of degradation products showed that MG was finally transformed into 4-aminobenzophenone and 4-aminophenol by CotA-laccase. The toxicity experiment of garlic root tip cell showed that the toxicity of MG metabolites decreased. In summary, CotA-laccase SF had a good application prospect for degrading malachite green.
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