title: A novel cold-adapted and glucose-tolerant GH1 β-glucosidase from Exiguobacterium antarcticum B7.
abstract: A novel GH1 β-glucosidase (EaBgl1A) from a bacterium isolated from Antarctica soil samples was recombinantly overexpressed in Escherichia coli cells and characterized. The enzyme showed unusual pH dependence with maximum activity at neutral pH and retention of high catalytic activity in the pH range 6 to 9, indicating a catalytic machinery compatible with alkaline conditions. EaBgl1A is also a cold-adapted enzyme, exhibiting activity in the temperature range from 10 to 40°C with optimal activity at 30°C, which allows its application in industrial processes using low temperatures. Kinetic characterization revealed an enzymatic turnover (Kcat) of 6.92s(-1) (cellobiose) and 32.98s(-1) (pNPG) and a high tolerance for product inhibition, which is an extremely desirable feature for biotechnological purposes. Interestingly, the enzyme was stimulated by up to 200 mM glucose, whereas the commercial cocktails tested were found fully inhibited at this concentration. These properties indicate EaBgl1A as a promising biocatalyst for biotechnological applications where low temperatures are required.
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
authors.forename: Elaine
authors.initials: E
authors.lastname: Crespim
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
authors.forename: Letícia M
authors.initials: LM
authors.lastname: Zanphorlin
authors.affiliation: Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
authors.forename: Flavio H M
authors.initials: FH
authors.lastname: de Souza
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
authors.forename: José A
authors.initials: JA
authors.lastname: Diogo
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
authors.forename: Alex C
authors.initials: AC
authors.lastname: Gazolla
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
authors.forename: Carla B
authors.initials: CB
authors.lastname: Machado
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Figueiredo
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
authors.forename: Amanda S
authors.initials: AS
authors.lastname: Sousa
authors.affiliation: Instituto Oceanográfico, Universidade de São Paulo, São Paulo, São Paulo, Brasil.
authors.forename: Felipe
authors.initials: F
authors.lastname: Nóbrega
authors.affiliation: Instituto Oceanográfico, Universidade de São Paulo, São Paulo, São Paulo, Brasil.
authors.forename: Vivian H
authors.initials: VH
authors.lastname: Pellizari
authors.affiliation: Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil.
authors.forename: Mário T
authors.initials: MT
authors.lastname: Murakami
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6192, CEP 13083-970, Campinas, São Paulo, Brasil. Electronic address: roberto.ruller@bioetanol.org.br.
authors.forename: Roberto
authors.initials: R
authors.lastname: Ruller
mesh_terms: D000220:Adaptation, Biological; D001406:Bacillaceae / Q000201:enzymology* / Q000235:genetics*; D002241:Carbohydrates / Q000737:chemistry; D002384:Catalysis; D003001:Cloning, Molecular; D003080:Cold Temperature; D004789:Enzyme Activation; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D002241:Carbohydrates; D001617:beta-Glucosidase
keywords: Cold adaptation; Exiguobacterium antarcticum B7; Glucose tolerance; β-Glucosidase