title: Expression of Two Novel β-Glucosidases from Chaetomium atrobrunneum in Trichoderma reesei and Characterization of the Heterologous Protein Products.
abstract: Two novel GH3 family thermostable β-glucosidases from the filamentous fungus Chaetomium atrobrunneum (CEL3a and CEL3b) were expressed in Trichoderma reesei, purified by two-step ion exchange chromatography, and characterized. Both enzymes were active over a wide range of pH as compared to Neurospora crassa β-glucosidase GH3-3, which was also expressed in T. reesei and purified. The optimum temperature of both C. atrobrunneum enzymes was around 60 °C at pH 5, and both enzymes had better thermal and pH stability and higher resistance to metallic compounds and to glucose inhibition than GH3-3. They also showed higher activity against oligosaccharides composed of glucose units and linked with β-1,4-glycosidic bonds and moreover, had higher affinity for cellotriose over cellobiose. In hydrolysis tests against Avicel cellulose and steam-exploded sugarcane bagasse, performed at 45 °C, particularly the CEL3a enzyme performed similarly to N. crassa GH3-3 β-glucosidase. Taking into account the thermal stability of the C. atrobrunneum β-glucosidases, they both represent promising alternatives as enzyme mixture components for improved cellulose saccharification at elevated temperatures.
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044, Espoo, Finland. annnacrrristina@gmail.com.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Colabardini
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044, Espoo, Finland.
authors.forename: Mari
authors.initials: M
authors.lastname: Valkonen
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044, Espoo, Finland.
authors.forename: Anne
authors.initials: A
authors.lastname: Huuskonen
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044, Espoo, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Siika-Aho
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044, Espoo, Finland.
authors.forename: Anu
authors.initials: A
authors.lastname: Koivula
authors.affiliation: Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Prêto, Universidade de São Paulo, Ribeirão Prêto, São Paulo, Brazil.|Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, Campinas, São Paulo, 13083-970, Brazil.
authors.forename: Gustavo H
authors.initials: GH
authors.lastname: Goldman
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044, Espoo, Finland.
authors.forename: Markku
authors.initials: M
authors.lastname: Saloheimo
mesh_terms: D002597:Chaetomium / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry; D013696:Temperature; D014242:Trichoderma / Q000235:genetics* / Q000378:metabolism; D001617:beta-Glucosidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; C036909:lignocellulose; D008031:Lignin; D001617:beta-Glucosidase
keywords: Bioethanol; Chaetomium atrobrunneum; Hydrolysis; Thermostability; β-glucosidase