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Purification and Characterization of a Thermo- and pH-Stable Laccase From the Litter-Decomposing Fungus Gymnopus luxurians and Laccase Mediator Systems for Dye Decolorization

Authors :
Yue Sun
Zi-Lu Liu
Bo-Yang Hu
Qing-Jun Chen
Ai-Zhen Yang
Qiu-Ying Wang
Xiao-Feng Li
Jia-Yan Zhang
Guo-Qing Zhang
Yong-Chang Zhao
Source :
Frontiers in Microbiology, Frontiers in Microbiology, Vol 12 (2021)
Publication Year :
2021
Publisher :
Frontiers Media SA, 2021.

Abstract

An extracellular laccase (GLL) was purified from fermentation broth of the litter-decomposing fungus Gymnopus luxurians by four chromatography steps, which resulted in a high specific activity of 118.82 U/mg, purification fold of 41.22, and recovery rate of 42.05%. It is a monomeric protein with a molecular weight of 64 kDa and N-terminal amino acid sequence of AIGPV TDLHI, suggesting that GLL is a typical fungal laccase. GLL demonstrated an optimum temperature range of 55°C–65°C and an optimum pH 2.2 toward 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). It displayed considerably high thermostability and pH stability with about 63% activity retained after 24 h at 50°C, and 86% activity retained after 24 h at pH 2.2, respectively. GLL was significantly enhanced in the presence of K+, Na+, and Mg2+ ions. It demonstrated Km of 539 μM and kcat/Km of 140 mM–1⋅s–1 toward ABTS at pH 2.2 and 37°C. Acetosyringone (AS) and syringaldehyde (SA) were the optimal mediators of GLL (0.4 U/ml) for dye decolorization with decolorization rates of about 60%–90% toward 11 of the 14 synthetic dyes. The optimum reaction conditions were determined to be mediator concentration of 0.1 mM, temperature range of 25°C –60°C, and pH 4.0. The purified laccase was the first laccase isolated from genus Gymnopus with high thermostability, pH stability, and effective decolorization toward dyes, suggesting that it has potentials for textile and environmental applications.

Details

ISSN :
1664302X
Volume :
12
Database :
OpenAIRE
Journal :
Frontiers in Microbiology
Accession number :
edsair.doi.dedup.....03edc4bafa78b972934fbcdebbb918c5
Full Text :
https://doi.org/10.3389/fmicb.2021.672620