Structure and sucrose hydrolysis activity of Saccharomyces cerevisiae aggregates

G.B.S.A., Laboratoire de Microbiologie Industrielle, Université Montpellier II, 34095 Montpellier Cedex 5, France.
Biotechnology and Bioengineering (Impact Factor: 4.13). 08/1992; 40(4):475-82. DOI: 10.1002/bit.260400405
Source: PubMed


The sucrose hydrolysis activity of dense spherical yeast flocs, cultivated on a sucrose medium in a continuous reactor with internal settler, is nearly proportional to the particle surface. From computer simulation, in good agreement with experimental determinations, the calculated sucrose penetration depth is in the range 0.2-0.3 mm, a dimension smaller than the usual diameter of strongly flocculating yeast particles. From specific gravity determinations, the flocs can be considered as homogeneous and cannot exhibit a fractal structure, reported in the literature for a number of microbial aggregates. However, the analysis of the sucrose hydrolysis rates reveals that the cell density may be lower in the outer layer of the flocs.

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    • "On the other hand, larger flocs will have a lower volume fraction of primary particles. Due to the relation between the aggregation number and the yeast floc size that can be described according to the theory for fractals, the volume fraction decreases with increasing floc size (Davis and Hunt, 1986; Fontana et al., 1991; Logan and Wilkinson, 1991). As for the floc formation rate and the floc splitting rate, the surface erosion rate also depends on particle concentration. "
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