title: A model for estimating the medium properties of Avicel to ethanol conversion.
abstract: Simultaneous saccharification and fermentation received an increasing level of attention over recent decades, with the primary focus on the development of improved enzyme and organism performance. Little literature is available on the effects of the various fermentation components on the apparent dynamic viscosity of the fermentation broth for use in reactor design and analysis. This work investigates density and settling properties of Avicel PH-101 particles and the effects of base medium composition, yeast concentration and cellulose particles on the apparent dynamic viscosity of the fermentation mixture. Dynamic viscosity measurements were obtained using a rotational viscometer equipped with a DG 26.7 double gap concentric cylinder measuring system. Results indicated that Avicel particles experience a greater drag force compared to similar sized spherical particles and have a measured density of 1,605.7 kg m(-3). The Ostwäld-de Waele formulation was used to describe the dynamic viscosity of the particles due to it shear-thinning nature. Correlation between the predicted particle effects and experimental results deviated with a root mean square error of 8.46 %.
authors.affiliation: Department of Mechanical and Mechatronic Engineering, University of Stellenbosch, Stellenbosch, South Africa. jmvz@sun.ac.za
authors.forename: J M
authors.initials: JM
authors.lastname: van Zyl
authors.forename: T M
authors.initials: TM
authors.lastname: Harms
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D000431:Ethanol / Q000378:metabolism*; D008954:Models, Biological; D012441:Saccharomyces cerevisiae / Q000254:growth & development*; D014783:Viscosity
chemical_list: D000431:Ethanol; D002482:Cellulose; C109691:microcrystalline cellulose