Identifying and characterizing the most significant β-glucosidase of the novel species Aspergillus saccharolyticus
The newly discovered fungal species Aspergillus saccharolyticus was found to produce a culture broth rich in β-glucosidase activity. In this present work, the main β-glucosidase of
A. saccharolyticus responsible for the efficient hydrolytic activity was identified, isolated, and characterized. Ion exchange chromatography was used to fractionate the culture broth, yielding fractions with high β-glucosidase activity and only 1 visible band on an SDS–PAGE
gel. Mass spectrometry analysis of this band gave peptide matches to β-glucosidases from aspergilli. Through a polymerase chain reaction approach using degenerate primers and genome walking, a 2919 bp sequence encoding the 860 amino acid BGL1 polypeptide was determined. BGL1 of A. saccharolyticus
has 91% and 82% identity with BGL1 from Aspergillus aculeatus and BGL1 from Aspergillus niger, respectively,
both belonging to Glycoside Hydrolase family 3. Homology modeling studies suggested β-glucosidase activity with preserved retaining mechanism and a wider catalytic pocket compared with other β-glucosidases. The bgl1 gene was heterologously expressed in Trichoderma reesei QM6a, purified, and characterized by enzyme kinetics studies. The enzyme can hydrolyze cellobiose, p-nitrophenyl-β-d-glucoside, and cellodextrins. The enzyme showed good thermostability,
was stable at 50 °C, and at 60 °C it had a half-life of approximately 6 h.
hydrolyse de la biomasse;
Document Type: Research Article
Section for Sustainable Biotechnology, Aalborg University Copenhagen, A.C. Meyers Vænge 15, 2450 København SV, Denmark.
MAX-lab, Lund University, Box 118, S-221 00 Lund, Sweden.
Chemical and Biological Process Development Group, Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99354, USA.
Publication date: September 1, 2012
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Published since 1954, this monthly journal contains new research in the field of microbiology including applied microbiology and biotechnology; microbial structure and function; fungi and other eucaryotic protists; infection and immunity; microbial ecology; physiology, metabolism and enzymology; and virology, genetics, and molecular biology. It also publishes review articles and notes on an occasional basis, contributed by recognized scientists worldwide.
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