ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Summary Optimum flocculating conditions for the yeast Kluyveromyces bulgaricus, in a glucose-bactopeptone medium, are obtained with 1.8 mM calcium for a carbohydrate/(nitrogenx6.25) ratio of 16. A comparative study of the wall phosphopeptidomannans extracted by pronase from flocculating and non-flocculating cultures showed that flocculation was associated with the following characteristics: increase of the amount and molecular weight of mannans, and higher phosphate contents; decrease of the amino acid and glucosamine rates, with a relative increase in hydroxy amino acids and decrease of basic amino acids; absence of galactose in both polymers although the flocculation was reversed by d-galactose. Acetolysis of the phosphopeptidomannan showed that the phenotypic expression of flocculation is correlated, at the structural level, with a lower content of N-acetylhexosamine residues linked to disaccharides and a higher content of phosphodisaccharides. According to these results the calcium dependent synthesis of a phosphopeptidomannan (instead of a N-acetylglucosaminopeptidomannan) with a larger and more branched structure, is necessary to allow the aggregation of the cells, via a presumed d-galactose sensible flocculating factor.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00253533
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