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.
Agger
T
T
Center for Process Biotechnology, Department of Biotechnology, Technical University of Denmark, Lyngby.
Spohr
A B
AB
Nielsen
J
J
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