title: Characterization of a Highly Thermostable and Organic Solvent-Tolerant Copper-Containing Polyphenol Oxidase with Dye-Decolorizing Ability from Kurthia huakuii LAM0618T.
abstract: Laccases are green biocatalysts that possess attractive advantages for the treatment of resistant environmental pollutants and dye effluents. A putative laccase-like gene, laclK, encoding a protein of 29.3 kDa and belonging to the Cu-oxidase_4 superfamily, was cloned and overexpressed in Escherichia coli. The purified recombinant protein LaclK (LaclK) was able to oxidize typical laccase substrates such as 2,6-dimethoxyphenol and l-dopamine. The characteristic adsorption maximums of typical laccases at 330 nm and 610 nm were not detected for LaclK. Cu2+ was essential for substrate oxidation, but the ratio of copper atoms/molecule of LaclK was determined to only be 1:1. Notably, the optimal temperature of LaclK was 85°C with 2,6-dimethoxyphenol as substrates, and the half-life approximately 3 days at 80°C. Furthermore, 10% (v/v) organic solvents (methanol, ethanol, isopropyl alcohol, butyl alcohol, Triton x-100 or dimethyl sulfoxide) could promote enzymatic activity. LaclK exhibited wide-spectrum decolorization ability towards triphenylmethane dyes, azo dyes and aromatic dyes, decolorizing 92% and 94% of Victoria Blue B (25 μM) and Ethyl Violet (25 μM), respectively, at a concentration of 60 U/L after 1 h of incubation at 60°C. Overall, we characterized a novel thermostable and organic solvent-tolerant copper-containing polyphenol oxidase possessing dye-decolorizing ability. These unusual properties make LaclK an alternative for industrial applications, particularly processes that require high-temperature conditions.
authors.affiliation: Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.|Biogas Institute of Ministry of Agriculture, Chengdu, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Guo
authors.affiliation: Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Biogas Institute of Ministry of Agriculture, Chengdu, China.
authors.forename: Yanwei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Chinese Academy of Fishery Sciences, Beijing, China.
authors.forename: Jinlong
authors.initials: J
authors.lastname: Song
authors.affiliation: Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Wang
authors.affiliation: Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Delong
authors.initials: D
authors.lastname: Kong
authors.affiliation: Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Dong
authors.affiliation: Biogas Institute of Ministry of Agriculture, Chengdu, China.
authors.forename: Mingxiong
authors.initials: M
authors.lastname: He
authors.affiliation: Biogas Institute of Ministry of Agriculture, Chengdu, China.
authors.forename: Guoquan
authors.initials: G
authors.lastname: Hu
authors.affiliation: Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Ruan
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D055162:Biocatalysis; D004156:Catechol Oxidase / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism*; D003300:Copper / Q000737:chemistry*; D004298:Dopamine / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D000068536:Bacillota / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D011748:Pyrogallol / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D012394:Rosaniline Dyes / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D012997:Solvents / Q000737:chemistry; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004396:Coloring Agents; D011994:Recombinant Proteins; D012394:Rosaniline Dyes; D012997:Solvents; D011748:Pyrogallol; C010120:pyrogallol 1,3-dimethyl ether; D003300:Copper; C034887:ethyl violet; D004156:Catechol Oxidase; D004298:Dopamine; C009662:Victoria blue B