title: Influence of a new axial impeller on K(L)a and xylanase production by Penicillium canescens 10-10c.
abstract: The effects of a new axial impeller (HTPG4) on oxygen volumetric transfer coefficient, K(L)a, and xylanase production by Penicillium canescens 10-10c were studied and compared for dual-impeller systems, one with one DT4 impeller below and one HTPG4 above (DT4-HTPG4) and one with two DT4 (DT4-DT4) impellers, in a 5-L bioreactor. The volumetric coefficient of oxygen transfer was measured in culture medium using a gassing-out method at different gassing rates and agitation speeds. We observed that the DT4-HTPG4 combination provided better K(L)a performance than the DT4-DT4 combination. The two combinations were also tested for their influence on xylanase production by a filamentous microorganism; P. canescens 10-10c. These experiments demonstrated that the DT4-HTPG4 combination impeller enhanced enzyme production up to 23% compared with the DT4-DT4 combination at an aeration rate of 1 vvm and an agitation speed of 600 rpm. The main cause for this difference is thought to be a higher shear stress generated by the DT4-DT4 combination, which damages the mycelium of P. canescens and decreases xylanase production.
authors.affiliation: Centre Wallon de Biologie Industrielle, Faculté Universitaire des Sciences Agronomiques, Gembloux, Belgium.
authors.forename: Yasser
authors.initials: Y
authors.lastname: Bakri
authors.forename: Philippe
authors.initials: P
authors.lastname: Jacques
authors.forename: Lin Kui
authors.initials: LK
authors.lastname: Shi
authors.forename: Philippe
authors.initials: P
authors.lastname: Thonart
mesh_terms: D019149:Bioreactors; D003470:Culture Media; D007700:Kinetics; D009172:Mycology / Q000295:instrumentation / Q000379:methods; D010100:Oxygen / Q000378:metabolism; D010313:Partial Pressure; D010407:Penicillium / Q000201:enzymology*; D013997:Time Factors; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D003470:Culture Media; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; D010100:Oxygen