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Production of a capsular polysaccharide by a marine filamentous fungus

P J Szaniszlo, C Wirsen, R Mitchell

    Journal of Bacteriology
    |November 1, 1968
    PubMed

    Insights

    The marine fungus Leptosphaeria albopunctata produces a viscous capsular polysaccharide rich in glucose. Its production is enhanced by specific salt concentrations and occurs during rapid fungal growth.

    Area of Science:

    • Marine Mycology
    • Biochemistry
    • Extracellular Polysaccharides

    Background:

    • The filamentous marine fungus Leptosphaeria albopunctata
    • High viscosity observed in spent culture medium
    • Viscosity attributed to capsular material

    Purpose of the Study:

    • Characterize the capsular material produced by L. albopunctata
    • Investigate nutritional and environmental factors influencing polysaccharide production
    • Determine the composition and metabolic fate of the capsular material

    Main Methods:

    • Microscopic examination using India ink
    • High-speed centrifugation of fungal cultures
    • Ethyl alcohol precipitation of culture medium
    • Anthrone test for polysaccharide detection
    • Gas chromatography for sugar analysis
    • Time course studies of nutritional requirements

    Main Results:

    • High viscosity due to extracellular capsular material
    • Polysaccharide composed mainly of glucose with some mannose
    • Maximal production during rapid growth phase on various sugars
    • Degradation and remetabolization in older cultures
    • Enhanced production with supra-optimal NaCl concentrations; KCl substitution possible
    • Requirement of MgCl(2) and CaCl(2) for capsule production

    Conclusions:

    • L. albopunctata synthesizes a glucose-rich polysaccharide capsule
    • Capsule production is linked to active growth and influenced by salinity and divalent cations
    • The capsular material is likely a storage product or involved in cellular protection
    • Further research needed on the specific roles of MgCl(2) and CaCl(2) in fungal metabolism

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