title: Expression of Aspergillus hemoglobin domain activities in Aspergillus oryzae grown on solid substrates improves growth rate and enzyme production.
abstract: DNA fragments coding for hemoglobin domains (HBD) were isolated from Aspergillus oryzae and Aspergillus niger. The HBD activities were expressed in A. oryzae by introduction of HBD gene fragments under the control of the promoter of the constitutively expressed gpdA gene. In the transformants, oxygen uptake was significantly higher, and during growth on solid substrates the developed biomass was at least 1.3 times higher than that of the untransformed wild-type strain. Growth rate of the HBD-activity-producing strains was also significantly higher compared to the wild type. During growth on solid cereal substrates, the amylase and protease activities in the extracts of the HBD-activity-producing strains were 30-150% higher and glucoamylase activities were at least 9 times higher compared to the wild-type strain. These results suggest that the Aspergillus HBD-encoding gene can be used in a self-cloning strategy to improve biomass yield and protein production of Aspergillus species.
authors.affiliation: Wageningen Center for Food Sciences (WCFS), Wageningen, The Netherlands. rob.tebiesebeke@frieslandfoods.com
authors.forename: Rob
authors.initials: R
authors.lastname: te Biesebeke
authors.forename: Amandine
authors.initials: A
authors.lastname: Boussier
authors.forename: Nick
authors.initials: N
authors.lastname: van Biezen
authors.forename: Machtelt
authors.initials: M
authors.lastname: Braaksma
authors.forename: Cees A M J J
authors.initials: CA
authors.lastname: van den Hondel
authors.forename: Willem M
authors.initials: WM
authors.lastname: de Vos
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Punt
mesh_terms: D000681:Amylases / Q000096:biosynthesis; D001234:Aspergillus niger / Q000502:physiology*; D001236:Aspergillus oryzae / Q000502:physiology*; D049109:Cell Proliferation; D015870:Gene Expression / Q000502:physiology; D024861:Genetic Enhancement / Q000379:methods*; D005087:Glucan 1,4-alpha-Glucosidase / Q000096:biosynthesis / Q000378:metabolism*; D006454:Hemoglobins / Q000235:genetics* / Q000378:metabolism*; D010100:Oxygen / Q000493:pharmacokinetics; D010447:Peptide Hydrolases / Q000096:biosynthesis; D015202:Protein Engineering / Q000379:methods; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D006454:Hemoglobins; D011994:Recombinant Proteins; D000681:Amylases; D005087:Glucan 1,4-alpha-Glucosidase; D010447:Peptide Hydrolases; D010100:Oxygen