A cellulolytic Hypocrea strain isolated from South American brave straw produces a modular xylanase.
Författare
Summary, in English
Cellulase-producing fungi from the Andean regions in Bolivia, an ecosystem characterized as an extreme arid highland, were studied. Thirty-two isolates were screened for presence of cellulase activity using carboxymethyl cellulose (CMC) as carbon source, and activity was confirmed using a filter paper assay. One isolate, denoted as BLT1C was selected from this screening, and sequence analysis of the internal transcribed spacer (ITS) classified the strain as Hypocrea lixii. The secretome of BLT1C showed high xylanase activity (compared to that of two reference Trichoderma reesei strains) when cultivated using brave straw, an abundant native grass from the area, as carbon source. SDS-PAGE analysis revealed three main protein-bands (18, 32 and 65kDa) and in-gel digestion and mass spectrometry combined with activity analysis showed that these proteins were active xylanases with molecular masses corresponding to (I) a single glycoside hydrolase family 11 catalytic module (18kDa), and (II, III) modular enzymes, with the GH11 catalytic domain connected to a module of unknown function (32kDa) or putatively connected to a GH7 catalytic module (65kDa). The N-terminal sequence of the 65kDa xylanase did not show significant sequence similarities to deposited sequences. The collected data on xylanase activity, molecular mass, GH11-sequence conservation, combined with lack of sequence similarities in the N-terminus show that the 65kDa band corresponds to a novel modular xylanase.
Avdelning/ar
Publiceringsår
2012
Språk
Engelska
Sidor
215-223
Publikation/Tidskrift/Serie
Carbohydrate Research
Volym
356
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Industrial Biotechnology
- Chemical Engineering
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1873-426X