Copper promotes E. coli laccase-mediated TNT biotransformation and alters the toxicity of TNT metabolites toward Tigriopus japonicus

doi:10.1016/j.ecoenv.2019.02.056

CNU IR > College of Sustainable Environment and Recreation > Dept. of Environmental Resources Management > Periodical Articles > Item 310902800/32609

Please use this identifier to cite or link to this item: https://ir.cnu.edu.tw/handle/310902800/32609

Title:	Copper promotes E. coli laccase-mediated TNT biotransformation and alters the toxicity of TNT metabolites toward Tigriopus japonicus
Authors:	Hsu, Duen-Wei Wang, Tzu-I. Da-Ji Huang(黃大俊) Pao, Yu-Jie Lin, Yuya A. Cheng, Ting-Wen Liang, Shih-Hsiung Chen, Chien-Yen Kao, Chih-Ming Sheu, Yih-Terng Chen, Chien-Cheng
Contributors:	Natl Kaohsiung Normal Univ, Dept Biotechnol Chia Nan Univ Pharm & Sci, Dept Environm Resources Management Natl Sun Yat Sen Univ, Dept Chem Natl Chung Cheng Univ, Dept Earth & Environm Sci Natl Sun Yat Sen Univ, Inst Environm Engn
Keywords:	Laccase TNT transformation Copper ion Toxicity Remediation
Date:	2019
Issue Date:	2020-07-29 13:51:58 (UTC+8)
Publisher:	ACADEMIC PRESS INC ELSEVIER SCIENCE
Abstract:	Although laccase is involved in the biotransformation of 2,4,6-trinitrotoluene (TNT), little is known regarding the effect of E. coli laccase on TNT biotransformation. In this study, E. coli K12 served as the parental strain to construct a laccase deletion strain and two laccase-overexpressing strains. These E. coil strains were used to investigate the effect of laccase together with copper ions on the efficiency of TNT biotransformation, the variety of TNT biotransformation products generated and the toxicity of the TNT metabolites. The results showed that the laccase level was not relevant to TNT biotransformation in the soluble fraction of the culture medium. Conversely, TNT metabolites varied in the insoluble fraction analyzed by thin-layer chromatography (TLC). The insoluble fraction from the laccase-null strain showed fewer and relatively fainter spots than those detected in the wild-type and laccase-overexpressing strains, indicating that laccase expression levels were interrelated determinants of the varieties and amounts of TNT metabolites produced. In addition, the aquatic invertebrate Tigriopus japonicus was used to assess the toxicity of the TNT metabolites. The toxicity of the TNT metabolite mixture increased when the intracellular laccase level in strains increased or when purified E. coli recombinant Laccase (rLaccase) was added to the culture medium. Thus, our results suggest that laccase activity must be considered when performing microbial TNT remediation.
Relation:	Ecotoxicology and Environmental Safety, v.173, pp.452-460
Appears in Collections:	[Dept. of Environmental Resources Management] Periodical Articles

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