- M.C. Jonathan (1)
- R. Joosten (1)
- M. Juvonen (1)
- S. Koutaniemi (1)
- M. Levisson (1)
- L.A.M. Pouvreau (1)
- G.J.G. Ruijter (1)
- H.A. Schols (2)
- M. Tenkanen (1)
- P.A. vanKuyk (1)
- R.P. Vries de (1)
- J. Wery (1)
- H.A.B. Wosten (1)
Distinct roles of carbohydrate esterase family CE16 acetyl esterases and polymer-acting acetyl xylan esterases in xylan deacetylation
Koutaniemi, S. ; Gool, M.P. van; Juvonen, M. ; Hinz, S.W.A. ; Schols, H.A. ; Tenkanen, M. - \ 2013
Journal of Biotechnology 168 (2013)4. - ISSN 0168-1656 - p. 684 - 692.
eucalyptus-globulus labill - trichoderma-reesei - alpha-glucuronidase - schizophyllum-commune - catalytic-properties - purification - aspen - mode - wood
Mass spectrometric analysis was used to compare the roles of two acetyl esterases (AE, carbohydrate esterase family CE16) and three acetyl xylan esterases (AXE, families CE1 and CE5) in deacetylation of natural substrates, neutral (linear) and 4-O-methyl glucuronic acid (MeGlcA) substituted xylooligosaccharides (XOS). AEs were similarly restricted in their action and apparently removed in most cases only one acetyl group from the non-reducing end of XOS, acting as exo-deacetylases. In contrast, AXEs completely deacetylated longer neutral XOS but had difficulties with the shorter ones. Complete deacetylation of neutral XOS was obtained after the combined action of AEs and AXEs. MeGlcA substituents partially restricted the action of both types of esterases and the remaining acidic XOS were mainly substituted with one MeGlcA and one acetyl group, supposedly on the same xylopyranosyl residue. These resisting structures were degraded to great extent only after inclusion of a-glucuronidase, which acted with the esterases in a synergistic manner. When used together with xylan backbone degrading endoxylanase and ß-xylosidase, both AE and AXE enhanced the hydrolysis of complex XOS equally.
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).