alpha-Amylase production in high cell density submerged cultivation of Aspergillus oryzae and A. nidulans.
The effect of biomass concentration on the formation of Aspergillus oryzae alpha-amylase during submerged cultivation with A. oryzae and recombinant A. nidulans strains has been investigated. It was found that the specific rate of alpha-amylase formation in chemostats decreased significantly with increasing biomass concentration in the range of approx. 2-12 g dry weight kg(-1). When using a recombinant A. nidulans strain in which the gene responsible for carbon catabolite repression of the A. oryzae alpha-amylase gene (creA) was deleted, no significant decrease in the specific rate of alpha-amylase formation was observed. On the basis of the experimental results, it is suggested that the low value of the specific alpha-amylase productivity observed at high biomass concentration is caused by slow mixing of the concentrated feed solution in the viscous fermentation medium.
Center for Process Biotechnology, Department of Biotechnology, Technical University of Denmark, Lyngby.
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Agger
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Spohr
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Nielsen
D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D001236:Aspergillus oryzae / Q000201:enzymology / Q000254:growth & development*; D018533:Biomass; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D003470:Culture Media; D005818:Genetic Engineering; D000516:alpha-Amylases / Q000378:metabolism*
D003470:Culture Media; D000516:alpha-Amylases