title: Improvement of foam breaking and oxygen-transfer performance in a stirred-tank fermenter.
abstract: This study examined a stirred-tank fermenter (STF) containing low-viscosity foaming liquids with an agitation impeller and foam-breaking impeller mounted on the same shaft. Results showed that the performance of the foam-breaking impeller can be improved by changing a conventional six-blade turbine impeller into a rod impeller as the agitation impeller. The volumetric oxygen-transfer coefficient, kLa, in the mechanical foam-control method (MFM) using a six-blade vaned disk as the foam-breaking impeller in the STF with the rod impeller was approximately five times greater than that of the chemical foam-control method (CFM) adding an anti-foaming agent in the STF with the six-blade turbine impeller. Application of the present method to the cultivation of Saccharomyces cerevisiae K-7 demonstrated that the cultivation time up to the maximum cell concentration was remarkably shorter than that achieved using a conventional CFM.
authors.affiliation: Department of Applied Chemistry and Biotechnology, Niigata Institute of Technology, Fujihashi, Kashiwazaki, 945-1103, Niigata, Japan. takesono@acb.niit.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takesono
authors.forename: Masayuki
authors.initials: M
authors.lastname: Onodera
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Toda
authors.forename: Masanori
authors.initials: M
authors.lastname: Yoshida
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Yamagiwa
authors.forename: Akira
authors.initials: A
authors.lastname: Ohkawa
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D049109:Cell Proliferation; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005285:Fermentation / Q000502:physiology; D005740:Gases / Q000737:chemistry; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D009038:Motion; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D010812:Physical Stimulation / Q000295:instrumentation* / Q000379:methods; D012212:Rheology / Q000295:instrumentation* / Q000379:methods; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D012996:Solutions
chemical_list: D005740:Gases; D012996:Solutions; D010100:Oxygen