TITLE

Constitutive expression of the Trichoderma reesei β-1,4-xylanase gene (xyn2) and the β-1,4-endoglucanase gene (egI) in Aspergillus niger in molasses and defined glucose media

AUTHOR(S)
Rose, S. H.; Van Zyl, W. H.
PUB. DATE
March 2002
SOURCE
Applied Microbiology & Biotechnology;Mar2002, Vol. 58 Issue 4, p461
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The xylanase II (xyn2)- and endoglucanase I (egI)-encoding regions of Trichoderma reesei QM6a were successfully expressed in Aspergillus niger D15 under the transcriptional control of the glyceraldehyde-6-phosphate dehydrogenase (gpd) promoter from A. niger and the glaA terminator of Aspergillus awamori. A stable xyn2 transformant produced β-xylanase activity of 8,000 nkat/ml and 5,000 nkat/ml in shake-flask cultures containing defined or 20% (v/v) molasses medium, respectively. The recombinant Xyn2 enzyme expressed highest activity at pH 5–6 and 50–60 °C and retained more than 75% of its activity after 3 h of incubation at 50 °C. A stable egI transformant produced endo-β-1,4-glucanase activity of 2,300 nkat/ml in shake-flask cultures containing defined media and about half the activity in 20% molasses medium. Maximum endoglucanase activity was obtained at pH 5 and 60 °C. Both Xyn2 and EgI retained >80% activity after incubation at 50 °C for 3 h. The heterologous Xyn2 and EgI represent a significant portion of the total extracellular proteins produced.
ACCESSION #
15681097

 

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