info:eu-repo/semantics/article
A thermostable laccase from Thermus sp. 2.9 and its potential for delignification of Eucalyptus biomass
Fecha
2019-02Registro en:
Navas, Laura Emilce; Martínez, Fernando D.; Taverna, María Eugenia; Fetherolf, Morgan M.; Eltis, Lindsay D.; et al.; A thermostable laccase from Thermus sp. 2.9 and its potential for delignification of Eucalyptus biomass; Springer Verlag Berlín; AMB Express; 9; 1; 2-2019; 1-10
2191-0855
CONICET Digital
CONICET
Autor
Navas, Laura Emilce
Martínez, Fernando D.
Taverna, María Eugenia
Fetherolf, Morgan M.
Eltis, Lindsay D.
Nicolau, Verónica
Estenoz, Diana Alejandra
Campos, Eleonora
Benintende, Graciela Beatriz
Berretta, Marcelo Facundo
Resumen
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 purifed 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 specifcity (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 saccharifcation. In conclusion, LAC_2.9 is a thermostable laccase with potential application in the delignifcation of lignocellulosic biomass.