Title
The effect of organic nitrogen sources on recombinant glucoamylase production by Aspergillus niger in chemostat culture
Author
Swift, R.J.
Karandikar, A.
Griffen, A.M.
Punt, P.J.
van den Hondel, C.A.M.J.J.
Robson, G.D.
Trinci, A.P.J.
Wiebe, M.G.
Centraal Instituut voor Voedingsonderzoek TNO
Publication year
2000
Abstract
Aspergillus niger B1, a recombinant strain carrying 20 extra copies of the native glucoamylase gene, was grown in glucose-limited chemostat cultures supplemented with various organic nitrogen sources (dilution rate 0.12 ± 0.01 h-1, pH 5.4). In cultures supplemented with L-alanine, L-methionine, casamino acids, or peptone, specific glucoamylase (GAM) production rapidly decreased to less than 20% of the initial level. Reducing the pH of the culture to 4.0 resulted in stable GAM production for up to 400 h. Morphological mutants (a light brown and a dark brown mutant) appeared in each fermentation and generally displaced B1. Light brown mutants had higher selection coefficients relative to B1 than dark brown mutants and became the dominant strain in all fermentations except those maintained at pH 4.0. Several mutants isolated from these cultures had reduced ability to produce GAM in batch culture, although few had lost copies of the glaA gene. Some mutants had methylated DNA. © 2000 Academic Press.
Subject
Biology
Aspergillus niger
Chemostat culture
Genetic instability
Glucoamylase
Nitrogen source
Recombinant protein
Alanine
Casamino acid
DNA
Fungal DNA
Fungal enzyme
Glucan 1,4 alpha glucosidase
Glucose
Methionine
Nitro derivative
Peptone
Aspergillus niger
Chemostat
Controlled study
Culture medium
DNA methylation
Enzyme metabolism
Enzyme synthesis
Fermentation
Fungal genetics
Fungus culture
Gene loss
Morphology
Nonhuman
PH
Priority journal
Strain difference
Aspergillus niger
Culture Media
Glucan 1,4-alpha-Glucosidase
Glucose
Hydrogen-Ion Concentration
Mutation
Nitrogen
Organic Chemicals
Recombinant Proteins
Aspergillus niger
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DOI
https://doi.org/10.1006/fgbi.2000.1241
TNO identifier
72250
ISSN
1087-1845
Source
Fungal Genetics and Biology, 31 (2), 125-133
Document type
article