title: Hydrodynamic characteristics and mixing behaviour of Sclerotium glucanicum culture fluids in an airlift reactor with an internal loop used for scleroglucan production.
abstract: The filamentous fungus, Sclerotium glucanicum NRRL 3006, was cultivated in a 0.008 m(3) airlift bioreactor with internal recirculation loop (ARL-IL) for production of the biopolymer, scleroglucan. The rheological behaviour of the culture fluid was characterised by measurement of the fluid consistency coefficient (K) and the flow behaviour index (n). Based on these measurements, the culture fluid changed from a low viscosity Newtonian system early in the process, to a viscous non-Newtonian (pseudoplastic) system. In addition, reactor hydrodynamics and mixing behaviour were characterised by measurement of whole mean gas hold-up (epsilon(g)), liquid re-circulation velocity (U(ld)) and mixing time (t(m)). Under identical process conditions, the effects of the viscosity of the culture fluid and air flow rate on epsilon(g), U(ld) and t(m) were examined and empirical correlations for epsilon(g), U(ld) and t(m) with both superficial velocity U(g) and consistency coefficient K were obtained and expressed separately. The correlations obtained are likely to describe the behaviour of real fungal culture fluids more accurately than previous correlations based on Newtonian or simulated non-Newtonian systems.
authors.affiliation: State Key Laboratory of Biochemical Engineering, Institute of Chemical Metallurgy, Chinese Academy of Sciences, P.O. Box 353, Beijing 100080, China.
authors.forename: X
authors.initials: X
authors.lastname: Kang
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: L M
authors.initials: LM
authors.lastname: Harvey
authors.forename: B
authors.initials: B
authors.lastname: McNeil
mesh_terms: D001203:Ascomycota / Q000254:growth & development*; D019149:Bioreactors; D001709:Biotechnology / Q000295:instrumentation* / Q000379:methods*; D003470:Culture Media; D005936:Glucans / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D012212:Rheology; D014783:Viscosity
chemical_list: D003470:Culture Media; D005936:Glucans; C045938:scleroglucan; D010100:Oxygen