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A thermostable laccase from Thermus sp. 2.9 and its potential for delignification of Eucalyptus biomass Navas, Laura E; Martínez, Fernando D; Taverna, María E; Fetherolf, Morgan M; Eltis, Lindsay D; Nicolau, Verónica; Estenoz, Diana; Campos, Eleonora; Benintende, Graciela B; Berretta, Marcelo F

Abstract

Laccases are multicopper oxidases that are being studied for their potential application in pretreatment strategies of lignocellulosic feedstocks for bioethanol production. Here, we report the expression and characterization of a predicted laccase (LAC_2.9) from the thermophilic bacterial strain Thermus sp. 2.9 and investigate its capacity to delignify lignocellulosic biomass. The purified enzyme displayed a blue color typical of laccases, showed strict copper dependence and retained 80% of its activity after 16 h at 70 °C. At 60 °C, the enzyme oxidized 2,2′-azino-di-(3-ethylbenzthiazoline sulfonate) (ABTS) and 2,6-dimethoxyphenol (DMP) at optimal pH of 5 and 6, respectively. LAC_2.9 had higher substrate specificity (kcat/KM) for DMP with a calculated value that accounts for one of the highest reported for laccases. Further, the enzyme oxidized a phenolic lignin model dimer. The incubation of steam-exploded eucalyptus biomass with LAC_2.9 and 1-hydroxybenzotriazole (HBT) as mediator changed the structural properties of the lignocellulose as evidenced by Fourier transform infrared (FTIR) spectroscopy and thermo-gravimetric analysis (TGA). However, this did not increase the yield of sugars released by enzymatic saccharification. In conclusion, LAC_2.9 is a thermostable laccase with potential application in the delignification of lignocellulosic biomass.

Item Metadata

Title
A thermostable laccase from Thermus sp. 2.9 and its potential for delignification of Eucalyptus biomass
Creator
Navas, Laura E; Martínez, Fernando D; Taverna, María E; Fetherolf, Morgan M; Eltis, Lindsay D; Nicolau, Verónica; Estenoz, Diana; Campos, Eleonora; Benintende, Graciela B; Berretta, Marcelo F
Publisher
Springer Berlin Heidelberg
Date Issued
2019-02-12
Description
Laccases are multicopper oxidases that are being studied for their potential application in pretreatment strategies of lignocellulosic feedstocks for bioethanol production. Here, we report the expression and characterization of a predicted laccase (LAC_2.9) from the thermophilic bacterial strain Thermus sp. 2.9 and investigate its capacity to delignify lignocellulosic biomass. The purified enzyme displayed a blue color typical of laccases, showed strict copper dependence and retained 80% of its activity after 16 h at 70 °C. At 60 °C, the enzyme oxidized 2,2′-azino-di-(3-ethylbenzthiazoline sulfonate) (ABTS) and 2,6-dimethoxyphenol (DMP) at optimal pH of 5 and 6, respectively. LAC_2.9 had higher substrate specificity (kcat/KM) for DMP with a calculated value that accounts for one of the highest reported for laccases. Further, the enzyme oxidized a phenolic lignin model dimer. The incubation of steam-exploded eucalyptus biomass with LAC_2.9 and 1-hydroxybenzotriazole (HBT) as mediator changed the structural properties of the lignocellulose as evidenced by Fourier transform infrared (FTIR) spectroscopy and thermo-gravimetric analysis (TGA). However, this did not increase the yield of sugars released by enzymatic saccharification. In conclusion, LAC_2.9 is a thermostable laccase with potential application in the delignification of lignocellulosic biomass.
Subject
Delignification; Eucalyptus globulus biomass; Redox mediator; Thermostable bacterial laccase; Thermus
Genre
Article
Type
Text
Language
eng
Date Available
2019-02-13
Provider
Vancouver : University of British Columbia Library
Rights
Attribution 4.0 International (CC BY 4.0)
DOI
10.14288/1.0376435
URI
http://hdl.handle.net/2429/68347
Affiliation
Science, Faculty of; Non UBC; Microbiology and Immunology, Department of
Citation
AMB Express. 2019 Feb 12;9(1):24
Publisher DOI
10.1186/s13568-019-0748-y
Peer Review Status
Reviewed
Scholarly Level
Faculty
Copyright Holder
The Author(s)
Rights URI
http://creativecommons.org/licenses/by/4.0/
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Attribution 4.0 International (CC BY 4.0)