title: Cultivation of shear stress sensitive microorganisms in disposable bag reactor systems.
abstract: Technical scale (≥5l) cultivations of shear stress sensitive microorganisms are often difficult to perform, as common bioreactors are usually designed to maximize the oxygen input into the culture medium. This is achieved by mechanical stirrers, causing high shear stress. Examples for shear stress sensitive microorganisms, for which no specific cultivation systems exist, are many anaerobic bacteria and fungi, such as basidiomycetes. In this work a disposable bag bioreactor developed for cultivation of mammalian cells was investigated to evaluate its potential to cultivate shear stress sensitive anaerobic Eubacterium ramulus and shear stress sensitive basidiomycetes Flammulina velutipes and Pleurotus sapidus. All cultivations were compared with conventional stainless steel stirred tank reactors (STR) cultivations. Good growth of all investigated microorganisms cultivated in the bag reactor was found. E. ramulus showed growth rates of μ=0.56 h⁻¹ (bag) and μ=0.53 h⁻¹ (STR). Differences concerning morphology, enzymatic activities and growth in fungal cultivations were observed. In the bag reactor growth in form of small, independent pellets was observed while STR cultivations showed intense aggregation. F. velutipes reached higher biomass concentrations (21.2 g l⁻¹ DCW vs. 16.8 g l⁻¹ DCW) and up to 2-fold higher peptidolytic activities in comparison to cell cultivation in stirred tank reactors.
authors.affiliation: Gottfried Wilhelm Leibniz Universität Hannover, Institute of Technical Chemistry, Callinstr. 5, 30167 Hannover, Germany. Electronic address: jonczyk@iftc.uni-hannover.de.
authors.forename: Patrick
authors.initials: P
authors.lastname: Jonczyk
authors.forename: Meike
authors.initials: M
authors.lastname: Takenberg
authors.forename: Steffen
authors.initials: S
authors.lastname: Hartwig
authors.forename: Sascha
authors.initials: S
authors.lastname: Beutel
authors.forename: Ralf G
authors.initials: RG
authors.lastname: Berger
authors.forename: Thomas
authors.initials: T
authors.lastname: Scheper
mesh_terms: D000693:Anaerobiosis; D018533:Biomass; D019149:Bioreactors; D003470:Culture Media; D005051:Eubacterium / Q000201:enzymology / Q000254:growth & development*; D055393:Flammulina / Q000201:enzymology / Q000254:growth & development*; D007218:Industrial Microbiology / Q000379:methods; D020076:Pleurotus / Q000201:enzymology / Q000254:growth & development*; D015203:Reproducibility of Results; D013312:Stress, Physiological
chemical_list: D003470:Culture Media
keywords: Anaerobic cultivation; Basidiomycetes; Eubacterium ramulus; Shear stress; Wave reactor