Rheological behaviour of concentrated yeast suspension

Fatile, I. A.

doi:10.1002/jctb.280350206

Cited by 9 publications

(1 citation statement)

References 7 publications

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“…If the rheological characterization is limited to one decade or more, and this is the case for several investigations [601, [603][604][605][606][607][608], the power law equation is the only possible model for correlating experimental data. This choice is particularly convenient for calculating power requirements for the agitation of non-gassed and gassed systems, since several contributions have been produced to improve the original approach suggested by Metzner and Otto [609] and by Calderbank and Moo-Young [610], as reviewed in [597,598].…”

Section: Fermentation Brothsmentioning

confidence: 99%

Rheology of polysaccharide systems

Lapasin

Pricl

1995

Rheology of Industrial Polysaccharides: Theory and Applications

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The transport properties and, specifically, the rheological behavior of real and complex materials such as polysaccharide systems can be significantly affected by several factors, mainly related to molecular and supermolecular features. Most of these factors are common to all polymeric systems, as they have universal character; others are peculiar to carbohydrate polymers. If we bear in mind the concepts discussed in §1.4, we can easily imagine for polysaccharides a variety of structural conditions much wider than that generally observed for synthetic polymers. On both molecular and supermolecular scales, polysaccharides possess special characteristics that reflect specific behavior so that different classes of materials can be identified.Let us consider the molecular scale first: at this level, the polymer backbone and its related features, such as its length in solution, shape, stitfuess and the eventual presence of ionizable groups, playa major role in determining the macroscopic properties of the system, including its rheology. Many of these molecular parameters correlate among themselves (e.g. chain stitfuess and length); others must be combined with external factors such as, for instance, the characteristics of the solvent medium. These latter may, in turn, exert an influence on the conformation adopted by the macromolecule in the medium itself, as well as on the possibility of forming supermolecular structures. In other words, changes in ionic strength, the nature of counterions, temperature or other solvent parameters may induce a conformational transition, thus modifying the hydrodynamic resistance of the macromolecule to flow. Also, if the polymer concentration is high enough, the variations described above may promote structural changes at a supermolecular level and, accordingly, modifications in the rheological behavior. Before leaving this brief comment on solvent characteristics we must mention the viscosity although, R. Lapasin et al. (eds.), Rheology of Industrial Polysaccharides: Theory and Applications

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Section: Fermentation Brothsmentioning

confidence: 99%

Rheology of polysaccharide systems

Lapasin

Pricl

1995

Rheology of Industrial Polysaccharides: Theory and Applications

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Yeast Physical (Shear) Stress: The Engineering Perspective

Stafford¹

2003

Brewing Yeast Fermentation Performance

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Biomass axial distribution in airlift bioreactor with yeast and plant cells

Assa

Bar

1991

Biotech & Bioengineering

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This study was aimed at determining the degree of biomass homogeneity in the various parts of an internal loop airlift bioreactor, thus verifying the assumption, often made in bioreactor studies, of a well-mixed liquid-biomass system. Following characterization of the hydrodynamics of the vessel with water, the axial biomass distribution in the riser and downcomer was determined for plant and yeast cell suspensions of 5.8, 8.5, and 12.5 g DW/L Phaseolus vulgaris and of 30 and 46 g DW/L Saccharomyces cerevisiae. The airlift bioreactor with a surface ratio A(D)/A(D) of 1.04 and aspect ratio of 4.95 was investigated under various aeration rates. The yeast cells were found to be distributed practically uniformly throughout the vessel at the aeration rates of 0.1-1.45 vvm. However, in the case of the denser and cluster-forming plant cells, a clear trend of a gradual bio-mass accumulation in the downcomer, a slightly lower but uniform biomass loading in the riser, and a slightly higher biomass concentration in the gas-liquid separator was observed at the lower aeration rates of 0.1-0.61 vvm. In the case of powderized calcium carbonate (55 g/L) often used in fermentations of organic acids, a slight trend of a gradual accumulation of solids towards the bottom parts in both the downcomer and riser was observed. A better representative sampling location, in terms of solids and biomass loading, seems to be in the middle part of the vessel. It is suggested that airlift bioreactors with higher aspect ratios (>5) may be prone to a more significant inhomogeneity of solids (biomass and particles).

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Rheological behaviour of concentrated yeast suspension

Cited by 9 publications

References 7 publications

Rheology of polysaccharide systems

Rheology of polysaccharide systems

Yeast Physical (Shear) Stress: The Engineering Perspective

Biomass axial distribution in airlift bioreactor with yeast and plant cells

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