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Título
Overexpression and lack of degradation of thaumatin in an aspergillopepsin A‐defective mutant of Aspergillus awamori containing an insertion in the pep A gene
Autor
Facultad/Centro
Área de conocimiento
Título de la revista
Applied Microbiology and Biotechnology
Número de la revista
6
Cita Bibliográfica
Moralejo, F. J., Cardoza, R. E., Gutiérrez, S., Sisniega, H., Faus, I., y Martı́n, J. (2000). Overexpression and lack of degradation of thaumatin in an aspergillopepsin a-defective mutant of Aspergillus awamori containing an insertion in the PEP A gene. Applied Microbiology and Biotechnology, 54(6), 772-777. https://doi.org/10.1007/s002530000463
Editorial
Springer Link
Fecha
2000-12
ISSN
0175-7598
Resumen
[EN] A gene encoding the sweet-tasting protein thaumatin (tha) with optimized codon usage was expressed in Aspergillus awamori. Mutants of A. awamori with reduced proteolytic activity were isolated. One of these mutants, named lpr66, contained an insertion of about 200 bp in the pepA gene, resulting in an inactive aspergillopepsin A. In vitro thaumatin degradation tests confirmed that culture broths of mutant lpr66 showed only a small thaumatin-degrading activity. A. awamori lpr66 has been used as host strain for thaumatin expression cassettes containing the tha gene under the control of either the cahB (cephalosporin acetylhydrolase) promoter of Acremonium chrysogenum or the gdhA (glutamate dehydrogenase) promoter of Aspergillus awamori. Residual proteolytic activities were repressed by using a mixture of glucose and sucrose as carbon sources and L-asparagine as nitrogen source. Degradation of thaumatin by acidic proteases was prevented by maintaining the pH value at 6.2 in the fermentor. Expression of cassettes containing the gdhA promoter was optimal in ammonium sulfate as nitrogen source, whereas transformants expressing the tha gene from the cahB promoter yielded higher thaumatin levels using L-asparagine as nitrogen source. Under optimal fermentation conditions, yields of 105 mg thaumatin/l were obtained, thus making this fermentation a process of industrial interest.
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SI
ID proyecto
- info:eu-repo/grantAgreement/EC/FP7/12345 o info:eu-repo/grantAgreement/JCyL/ADE 08-2/99/LE/ 0001
- (info:eu-repo/grantAgreement/EC/FP7/12345 o info:eu-repo/grantAgreement/ERDF/1FD-1111-C02-01
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