title: Efficiency of Blenke cascade system for continuous bio-ethanol fermentation.
abstract: A gas lift-system with inserts (so-called Blenke cascade system) for continuous bio-ethanol fermentation was constructed. Gas introduced at the bottom of the column created toroidal vortices in the fluid cells between inserts, enhancing mixing and improving residence time behavior without stirring equipment being necessary. The parameters mash type, start-up strategy, yeast-recycle model and yeast separation were studied concerning the efficiency of the ethanol production. The best results obtained were for a filtered mash, a double saccharification principle (DSP), a batch start-up strategy, an activation-recycle model and a lamella settler connected in series with a small conventional gravitational settler for yeast cells separation. Using this system, the fermentation residence time was τ=4-5.5h, depending on substrate type. Eighty five percent of the yeast cells could be separated. High volumetric ethanol productivity (Q(p)=20.43g/Lh) and yield E(y)=98% were achieved. Continuous fermentation, yeast recycling and sedimentation were contamination-free processes.
authors.affiliation: Department of Fermentation Technology, Institute of Food Science and Biotechnology, Hohenheim Universität, Garbenstrasse 23, 70599 Stuttgart, Germany. ntinepo@yahoo.com
authors.forename: Jean Nepomuscene
authors.initials: JN
authors.lastname: Ntihuga
authors.forename: Thomas
authors.initials: T
authors.lastname: Senn
authors.forename: Peter
authors.initials: P
authors.lastname: Gschwind
authors.forename: Reinhard
authors.initials: R
authors.lastname: Kohlus
mesh_terms: D056804:Biofuels / Q000032:analysis*; D001709:Biotechnology / Q000379:methods*; D050260:Carbohydrate Metabolism; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013379:Substrate Specificity; D013395:Sucrose / Q000378:metabolism; D013696:Temperature
chemical_list: D056804:Biofuels; D000431:Ethanol; D013395:Sucrose