The effect of pH on glucoamylase production, glycosylation and chemostat evolution of Aspergillus niger
The effect of ambient pH on production and glycosylation of glucoamylase (GAM) and on the generation of a morphological mutant produced by Aspergillus niger strain B1 (a transformant containing an additional 20 copies of the homologous GAM glaA gene) was studied. We have shown that a change in the p...
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| Format: | Article |
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Elsevier
2001
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| Online Access: | https://eprints.nottingham.ac.uk/45260/ |
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| author | Wallis, Gregg L.F. Swift, Richard J. Atterbury, Robert J. Trappe, Susanne Rinas, Ursula Hemming, Frank W. Wiebe, Marilyn G. Trinci, Anthony P.J. Peberdy, John F. |
| author_facet | Wallis, Gregg L.F. Swift, Richard J. Atterbury, Robert J. Trappe, Susanne Rinas, Ursula Hemming, Frank W. Wiebe, Marilyn G. Trinci, Anthony P.J. Peberdy, John F. |
| author_sort | Wallis, Gregg L.F. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | The effect of ambient pH on production and glycosylation of glucoamylase (GAM) and on the generation of a morphological mutant produced by Aspergillus niger strain B1 (a transformant containing an additional 20 copies of the homologous GAM glaA gene) was studied. We have shown that a change in the pH from 4 to 5.4 during continuous cultivation of the A. niger B1 strain instigates or accelerates the spontaneous generation of a morphological mutant (LB). This mutant strain produced approx. 50% less extracellular protein and GAM during both chemostat and batch cultivation compared to another strain with parental-type morphology (PS). The intracellular levels of GAM were also lower in the LB strain. In addition, cultivation of the original parent B1 strain in a batch-pulse bioreactor at pH 5.5 resulted in a 9-fold drop in GAM production and a 5-fold drop in extracellular protein compared to that obtained at pH 4. Glycosylation analysis of the glucoamylases purified from shake-flask cultivation showed that both principal forms of GAM secreted by the LB strain possessed enhanced galactosylation (2-fold), compared to those of the PS. Four diagnostic methods (immunostaining, mild methanolysis, mild acid hydrolysis and β-galactofuranosidase digestion) provided evidence that the majority of this galactose was of the furanoic conformation. The GAMs produced during batch-pulse cultivation at pH 5.5 similarly showed an approx. 2-fold increase in galactofuranosylation compared to pH 4. Interestingly, in both cases the increased galactofuranosylation appears primarily restricted to the O-linked glycan component. Ambient pH therefore regulates both GAM production and influences its glycosylation. |
| first_indexed | 2025-11-14T19:58:29Z |
| format | Article |
| id | nottingham-45260 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:58:29Z |
| publishDate | 2001 |
| publisher | Elsevier |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-452602020-05-04T16:25:31Z https://eprints.nottingham.ac.uk/45260/ The effect of pH on glucoamylase production, glycosylation and chemostat evolution of Aspergillus niger Wallis, Gregg L.F. Swift, Richard J. Atterbury, Robert J. Trappe, Susanne Rinas, Ursula Hemming, Frank W. Wiebe, Marilyn G. Trinci, Anthony P.J. Peberdy, John F. The effect of ambient pH on production and glycosylation of glucoamylase (GAM) and on the generation of a morphological mutant produced by Aspergillus niger strain B1 (a transformant containing an additional 20 copies of the homologous GAM glaA gene) was studied. We have shown that a change in the pH from 4 to 5.4 during continuous cultivation of the A. niger B1 strain instigates or accelerates the spontaneous generation of a morphological mutant (LB). This mutant strain produced approx. 50% less extracellular protein and GAM during both chemostat and batch cultivation compared to another strain with parental-type morphology (PS). The intracellular levels of GAM were also lower in the LB strain. In addition, cultivation of the original parent B1 strain in a batch-pulse bioreactor at pH 5.5 resulted in a 9-fold drop in GAM production and a 5-fold drop in extracellular protein compared to that obtained at pH 4. Glycosylation analysis of the glucoamylases purified from shake-flask cultivation showed that both principal forms of GAM secreted by the LB strain possessed enhanced galactosylation (2-fold), compared to those of the PS. Four diagnostic methods (immunostaining, mild methanolysis, mild acid hydrolysis and β-galactofuranosidase digestion) provided evidence that the majority of this galactose was of the furanoic conformation. The GAMs produced during batch-pulse cultivation at pH 5.5 similarly showed an approx. 2-fold increase in galactofuranosylation compared to pH 4. Interestingly, in both cases the increased galactofuranosylation appears primarily restricted to the O-linked glycan component. Ambient pH therefore regulates both GAM production and influences its glycosylation. Elsevier 2001-08-15 Article PeerReviewed Wallis, Gregg L.F., Swift, Richard J., Atterbury, Robert J., Trappe, Susanne, Rinas, Ursula, Hemming, Frank W., Wiebe, Marilyn G., Trinci, Anthony P.J. and Peberdy, John F. (2001) The effect of pH on glucoamylase production, glycosylation and chemostat evolution of Aspergillus niger. Biochimica et Biophysica Acta - General Subjects, 1527 (3). pp. 112-122. ISSN 0304-4165 pH Glucoamylase Galactofuranose Aspergillus niger https://doi.org/10.1016/S0304-4165(01)00145-3 doi:10.1016/S0304-4165(01)00145-3 doi:10.1016/S0304-4165(01)00145-3 |
| spellingShingle | pH Glucoamylase Galactofuranose Aspergillus niger Wallis, Gregg L.F. Swift, Richard J. Atterbury, Robert J. Trappe, Susanne Rinas, Ursula Hemming, Frank W. Wiebe, Marilyn G. Trinci, Anthony P.J. Peberdy, John F. The effect of pH on glucoamylase production, glycosylation and chemostat evolution of Aspergillus niger |
| title | The effect of pH on glucoamylase production, glycosylation and chemostat evolution of Aspergillus niger |
| title_full | The effect of pH on glucoamylase production, glycosylation and chemostat evolution of Aspergillus niger |
| title_fullStr | The effect of pH on glucoamylase production, glycosylation and chemostat evolution of Aspergillus niger |
| title_full_unstemmed | The effect of pH on glucoamylase production, glycosylation and chemostat evolution of Aspergillus niger |
| title_short | The effect of pH on glucoamylase production, glycosylation and chemostat evolution of Aspergillus niger |
| title_sort | effect of ph on glucoamylase production, glycosylation and chemostat evolution of aspergillus niger |
| topic | pH Glucoamylase Galactofuranose Aspergillus niger |
| url | https://eprints.nottingham.ac.uk/45260/ https://eprints.nottingham.ac.uk/45260/ https://eprints.nottingham.ac.uk/45260/ |