title: Overexpression of a novel thermostable and chloride-tolerant laccase from Thermus thermophilus SG0.5JP17-16 in Pichia pastoris and its application in synthetic dye decolorization.
abstract: Laccases have been used for the decolorization and detoxification of synthetic dyes due to their ability to oxidize a wide variety of dyes with water as the sole byproduct. A putative laccase gene (LacTT) from Thermus thermophilus SG0.5JP17-16 was screened using the genome mining approach, and it was highly expressed in Pichia pastoris, yielding a high laccase activity of 6130 U/L in a 10-L fermentor. The LacTT open reading frame encoded a protein of 466 amino acid residues with four putative Cu-binding regions. The optimal pH of the recombinant LacTT was 4.5, 6.0, 7.5 and 8.0 with 2,2'-azino-bis(3-ethylbenzothazoline-6-sulfonic acid) (ABTS), syringaldazine (SGZ), guaiacol, and 2,6-dimethoxyphenol (2,6-DMP) as the substrate, respectively. The optimal temperature of LacTT was 90°C with guaiacol as the substrate. LacTT was highly stable at pH 4.0-11.0 and thermostable at 40°C-90°C, confirming that it is a pH-stable and thermostable laccase. Furthermore, LacTT also exhibited high tolerance to halides such as NaCl, NaBr and NaF, and decolorized 100%, 94%, 94% and 73% of Congo Red, Reactive Black B and Reactive Black WNN, and Remazol Brilliant Blue R, respectively. Interestingly, addition of high concentration of NaCl increased the RBBR decolorization efficiency of LacTT. These results suggest that LacTT is a good candidate for industrial applications such as dyestuff processing and degradation of dyes in textile wastewaters.
authors: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China.
authors: Huiping
authors: H
authors: Liu
authors: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China.
authors: Yu
authors: Y
authors: Cheng
authors: College of Food Science and Engineering, South China Agricultural University, Guangzhou, Guangdong 510642, China.
authors: Bing
authors: B
authors: Du
authors: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China.
authors: Chaofan
authors: C
authors: Tong
authors: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China.
authors: Shuli
authors: S
authors: Liang
authors: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China.
authors: Shuangyan
authors: S
authors: Han
authors: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China.
authors: Suiping
authors: S
authors: Zheng
authors: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China.
authors: Ying
authors: Y
authors: Lin
mesh_terms: D000880:Anthraquinones / Q000737:chemistry / Q000378:metabolism; D003001:Cloning, Molecular; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism*; D003224:Congo Red / Q000737:chemistry / Q000378:metabolism; D006139:Guaiacol / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D042845:Laccase / Q000235:genetics / Q000378:metabolism*; D009282:Naphthalenesulfonates / Q000737:chemistry / Q000378:metabolism; D010843:Pichia / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D013379:Substrate Specificity; D013696:Temperature; D016963:Thermus thermophilus / Q000201:enzymology*
chemical_list: D000880:Anthraquinones; D004396:Coloring Agents; D009282:Naphthalenesulfonates; D011994:Recombinant Proteins; D003224:Congo Red; D006139:Guaiacol; D042845:Laccase; C024758:Remazol Brilliant Blue R; C063421:Remazol black B