Title
Branching mutants of Aspergillus oryzae with improved amylase and protease production on solid substrates
Author
te Biesebeke, R.
Record, E.
van Biezen, N.
Heerikhuisen, M.
Franken, A.
Punt, P.J.
van den Hondel, C.A.M.J.J.
TNO Kwaliteit van Leven
Publication year
2005
Abstract
To study the relation between the number of hyphal tips and protein secretion during growth on a solid substrate, we have constructed two mutant strains of Aspergillus oryzae with increased hyphal branching. We have analysed hydrolytic enzyme activities during growth on wheat kernels (WK) of A. oryzae strains carrying the disrupted allele of the pclA gene encoding a secretion pathway specific (KEX2-like) endo-protease and the disrupted allele of the pg/pi-tp gene encoding a phosphatidylglycerol/phosphatidylinositol transfer protein. The biomass levels produced by the pclA and pg/pi-tp disrupted strains on wheat-based solid media were similar as found for the wild-type strain. However, the pclA disrupted strain showed much more compact colony morphology than the other two strains. Sporulation of the pclA and pg/pi-tp disrupted strains occurred, respectively, 2 days and 1 day later, compared to the wild type during fermentation on ground WK. During surface growth, microscopic analysis revealed that the hyphal growth unit length (L hgu) of the pclA and pg/pi-tp disrupted strains was, on average, 50 and 74% of that of the wild-type strain. This implies that in both mutant strains, a higher branching frequency occurs than in the wild-type strain. Compared to the wild-type strain, the pclA and pg/pi-tp disrupted strains produced at least 50% more amylase, at least 100% more glucoamylase and at least 90% more protease activity levels after growth on WK. These results support the hypothesis that branching mutants with an increased branching frequency can improve the solid state fermentation process. © Springer-Verlag 2005.
Subject
Biology
Biotechnology
Enzyme kinetics
Enzymes
Fermentation
Growth kinetics
Hydrolysis
Microorganisms
Substrates
Yeast
Amylase
Branching mutants
Hydrolytic enzymes
Solid substrates
Mutagenesis
amylase
carrier protein
glucan 1,4 alpha glucosidase
phosphatidylglycerol
phosphatidylinositol
proteinase
fungus
gene expression
protein
allele
article
Aspergillus oryzae
enzyme activity
enzyme synthesis
fermentation
fungal biomass
fungal genetics
fungal strain
fungus growth
fungus hyphae
fungus mutant
genetic code
hydrolysis
microscopy
nonhuman
protein secretion
seed kernel
solid
sporogenesis
wheat
wild type
Amylases
Aspergillus oryzae
Biomass
Fungal Proteins
Gene Deletion
Glucan 1,4-alpha-Glucosidase
Hyphae
Morphogenesis
Mutagenesis, Insertional
Mutation
Peptide Hydrolases
Phospholipid Transfer Proteins
Spores, Fungal
Triticum
Aspergillus oryzae
Fungi
Triticum aestivum
To reference this document use:
http://resolver.tudelft.nl/uuid:4001a778-12e2-4da1-b4ee-3a761b514b51
DOI
https://doi.org/10.1007/s00253-005-1968-4
TNO identifier
238787
ISSN
0175-7598
Source
Applied Microbiology and Biotechnology, 69 (1), 44-50
Document type
article