2019-02-262019-02-262019-04-02Navas, Laura; Martinez, Fernando; Taverna, María Eugenia; Fetherol, Morgan; Eltis, Lindsay; Nicolau, Verónica; Estenoz, Diana; Campos, Eleonora; Benintende, Graciela; Berretta, Marcelo; A thermostable laccase from Thermus sp. 2.9 and its potential for delignification of Eucalyptus biomass; AMB Express; 2 de abril del 2019.http://hdl.handle.net/20.500.12272/3436Laccases 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.application/pdfenginfo:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/delignificationEucalyptus globulus biomassredox mediatorthermostable bacterial laccasethermusinfo:eu-repo/semantics/articleAtribución-NoComercial-CompartirIgual 4.0 InternacionalAtribución-NoComercial-CompartirIgual 4.0 Internacionalhttp://10.1186/s13568-019-0748-y