title: Effect of deletion of chitin synthase genes on mycelial morphology and culture viscosity in Aspergillus oryzae.
abstract: The objective of this study was to quantify the effect of disrupting two chitin synthases, chsB and csmA, on the morphology and rheology during batch cultivation of Aspergillus oryzae. The rheological properties were characterized in batch cultivations at different biomass concentrations (from 3.4-22.5 g kg(-1) biomass) and the power-law model adequately described the rheological properties. In the cultivations there were pellets, clumps, and freely dispersed hyphal elements. The different morphological fractions were quantified using image analysis. The apparent viscosity of the fermentation broth was significantly affected by the biomass concentration, the morphology, and also by pH. The chsB disruption strain had lower consistency index K values for all biomass concentrations investigated, which is a desirable trait for industrial Aspergillus fermentations.
authors.affiliation: Center for Process Biotechnology, BioCentrum-DTU, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Müller
authors.forename: Kim
authors.initials: K
authors.lastname: Hansen
authors.forename: Peter
authors.initials: P
authors.lastname: Szabo
authors.forename: Jens
authors.initials: J
authors.lastname: Nielsen
mesh_terms: D001236:Aspergillus oryzae / Q000166:cytology* / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D019149:Bioreactors; D002455:Cell Division / Q000235:genetics; D002460:Cell Line; D002687:Chitin Synthase / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D003470:Culture Media / Q000737:chemistry*; D017353:Gene Deletion; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D006863:Hydrogen-Ion Concentration; D025301:Hyphae / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D016297:Mutagenesis, Site-Directed; D025282:Mycelium / Q000166:cytology* / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods; D012680:Sensitivity and Specificity; D013045:Species Specificity; D014783:Viscosity
chemical_list: D003470:Culture Media; D002687:Chitin Synthase