A novel thermostable and glucose-tolerant β-glucosidase from Fervidobacterium islandicum.

Dina Jabbour, Barbara Klippel, Garabed Antranikian

Institute of Technical Microbiology, Hamburg University of Technology, Kasernenstr. 12, 21073, Hamburg, Germany.

Applied microbiology and biotechnology 2012 Mar

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An open reading frame (ORF) encoding the enzyme β-glucosidase from the extremely thermophilic bacterium Fervidobacterium islandicum has been identified, cloned and sequenced. The bgl1A gene was cloned in a pET-Blue1 vector and transformed in Escherichia coli, resulting in high-level expression of β-glucosidase FiBgl1A that was purified to homogeneity in a two-step purification. FiBgl1A is composed of 459 amino acid residues and showed high homology to glycoside hydrolase family 1 proteins. It exhibited highest activity towards p-nitrophenyl-β-D: -glucopyranoside with an optimum activity at pH 6.0 and 7.0 and at 90 °C. The enzyme is resistant to glucose inhibition. Furthermore, it did not require divalent cations for activity, nor was it affected by the addition of p-chloromercuribenzoate (10 mM), EDTA (10 mM), urea (10 mM) or dithiothreitol (10 mM). Addition of surfactants (with the exception of SDS) and a number of solvents enhanced the activity of FiBgl1A. It also displayed remarkable activity across a broad temperature range (80-100 °C). The thermoactivity and thermostability of FiBgl1A and its resistance to denaturing and reducing agents make this enzyme a potential candidate for industrial applications.

Citation

Dina Jabbour, Barbara Klippel, Garabed Antranikian. A novel thermostable and glucose-tolerant β-glucosidase from Fervidobacterium islandicum. Applied microbiology and biotechnology. 2012 Mar;93(5):1947-56