Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    We will mail you new results for this query: keywords==degrading enzymes
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Hemicellulase production in Chrysosporium lucknowense C1
Hinz, S.W.A. ; Pouvreau, L.A.M. ; Joosten, R. ; Bartels, J. ; Jonathan, M.C. ; Wery, J. ; Schols, H.A. - \ 2009
Journal of Cereal Science 50 (2009). - ISSN 0733-5210 - p. 318 - 323.
recombinant saccharomyces-cerevisiae - fungus trichoderma-reesei - alpha-glucuronidase - aspergillus-niger - wheat arabinoxylan - ferulic acid - feruloylated oligosaccharides - degrading enzymes - maize bran - xylose
Filamentous fungi are widely used for enzyme production for the biofuel industry. The ascomycetous fungus Chrysosporium lucknowense C1 was isolated as a natural producer of neutral cellulases. It is at present an attractive alternative to well known fungi like Aspergillus sp. and Trichoderma reesei for protein production on a commercial scale. Besides many cellulases, a large number of hemicellulases (particularly xylanases and arabinofuranosidases) and esterases (acetyl xylan esterases and ferulic acid esterases) encoding genes have also been identified in the C1 genome. Many of these extracellular enzymes have been selectively expressed in C1 and then purified and characterized. Four arabinofuranosidases, two acetyl xylan esterases, two ferulic acid esterases, an a-glucuronidase and four xylanases have been purified and characterized. All these enzymes were found to be active towards arabinoxylans, demonstrating the high potential of C1 as a producer of hemicellulolytic enzymes.
Regulation of pentose catabolic pathway genes of Aspergillus niger
Groot, M.J.L. de; Dool, C. van den; Wosten, H.A.B. ; Levisson, M. ; vanKuyk, P.A. ; Ruijter, G.J.G. ; Vries, R.P. de - \ 2007
Food Technology and Biotechnology 45 (2007)2. - ISSN 1330-9862 - p. 134 - 138.
transcriptional activator xlnr - d-xylose - l-arabinose - alpha-glucuronidase - degrading enzymes - kinase gene - expression - nidulans - polysaccharides - degradation
The aim of this study was to obtain a better understanding of the pentose catabolism in Aspergillus niger and the regulatory systems that affect it. To this end, we have cloned and characterised the genes encoding A. niger L-arabitol dehydrogenase (ladA) and xylitol dehydrogenase (xdhA), and compared the regulation of these genes to other genes of the pentose catabolic pathway. This demonstrated that activation of the pathway depends on two transcriptional regulators, the xylanolytic activator (XlnR) and an unidentified L-arabinose specific regulator (AraR). These two regulators affect those genes of the pentose catabolic pathway that are related to catabolic conversion of their corresponding inducers (D-xylose and L-arabinose, respectively).
Metabolic control analysis of Aspergillus niger L-arabinose catabolism
Groot, M.J.L. de; Prathumpai, W. ; Visser, J. ; Ruijter, G.J.G. - \ 2005
Biotechnology Progress 21 (2005)6. - ISSN 8756-7938 - p. 1610 - 1616.
alpha-l-arabinofuranosidase - enzyme-catalyzed reactions - d-xylose - extracellular arabinases - degrading enzymes - gene-expression - pichia-stipitis - reductase gene - nidulans - purification
A mathematical model of the L-arabinose/D-xylose catabolic pathway of Aspergillus niger was constructed based on the kinetic properties of the enzymes. For this purpose L-arabinose reductase, L-arabitol dehydrogenase and D-xylose reductase were purified using dye-affinity chromatography, and their kinetic properties were characterized. For the other enzymes of the pathway the kinetic data were available from the literature. The metabolic model was used to analyze flux and metabolite concentration control of the L-arabinose catabolic pathway. The model demonstrated that flux control does not reside at the enzyme following the intermediate with the highest concentration, L-arabitol, but is distributed over the first three steps in the pathway, preceding and following L-arabitol. Flux control appeared to be strongly dependent on the intracellular L-arabinose concentration. At 5 mM intracellular L-arabinose, a level that resulted in realistic intermediate concentrations in the model, flux control coefficients for L-arabinose reductase, L-arabitol dehydrogenase and L-xylulose reductase were 0.68, 0.17 and 0.14, respectively. The analysis can be used as a guide to identify targets for metabolic engineering aiming at either flux or metabolite level optimization of the L-arabinose catabolic pathway of A. niger. Faster L-arabinose utilization may enhance utilization of readily available organic waste containing hemicelluloses to be converted into industrially interesting metabolites or valuable enzymes or proteins.
Isolation and characterization of two specific regulatory Aspergillus niger mutants shows antagonistic regulation of arabinan and xylan metabolism
Groot, M.J.L. de; Vondervoort, P.J.I. van de; Vries, R.P. de; Kuyk, P.A. van; Ruijter, G.J.G. ; Visser, J. - \ 2003
Microbiology 149 (2003). - ISSN 1350-0872 - p. 1183 - 1191.
alpha-l-arabinofuranosidase - transcriptional activator xlnr - gene-expression - d-xylose - degrading enzymes - degradation - induction - nidulans - cloning - construction
This paper describes two Aspergillus niger mutants (araA and araB) specifically disturbed in the regulation of the arabinanase system in response to the presence of L-arabinose. Expression of the three known L-arabinose-induced arabinanolytic genes, abfA, abfB and abnA, was substantially decreased or absent in the araA and araB strains compared to the wild-type when incubated in the presence of L-arabinose or L-arabitol. In addition, the intracellular activities Of L-arabitol dehydrogenase and L-arabinose reductase, involved in L-arabinose catabolism, were decreased in the araA and araB strains. Finally, the data show that the gene encoding D-xylulose kinase, xkiA, is also under control of the arabinanolytic regulatory system. L-Arabitol, most likely the true inducer of the arabinanolytic and L-arabinose catabolic genes, accumulated to a high intracellular concentration in the araA and araB mutants. This indicates that the decrease of expression of the arabinanolytic genes was not due to lack of inducer accumulation. Therefore, it is proposed that the araA and araB mutations are localized in positive-acting components of the regulatory system involved in the expression of the arabinanase-encoding genes and the genes encoding the L-arabinose catabolic pathway.
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