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Fungi

Fungi. What are they? Eukaryotic microorganisms heterotrophic mostly saprophytic (feed on dead remains) non-pigmented Importance mineralization (nutrient cycling) not faecal pathogens Size and morphology hyphae (filamentous) 5 - 10 m wide, long (mm - m)bundles of mycelia

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Fungi

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  1. Fungi What are they? • Eukaryotic microorganisms • heterotrophic mostly saprophytic (feed on dead remains) • non-pigmented Importance • mineralization (nutrient cycling) • not faecal pathogens Size and morphology • hyphae (filamentous) 5 - 10 m wide, long (mm - m)bundles of mycelia • shared cytoplasm (coenocyic) • unicellular (yeasts) • produce many types of spores (e.g. conidia, chlamydospores) Cell Wall • cellulose and chitin Reproduction • sexual and asexual

  2. Physiology of Fungi No chlorophyll therefore produce extra-cellular enzymes. Heterotrophic nutrition. Parasitic or Saprophytic Very slow rate of growth cf. bacteria. Environmental Requirements 1. Nutrients - Only organic C C10H17O6N - or Organic C + N } i.e. low ratio N:C and some need therefore tolerate vitamins N deficiency. 2. Moisture relatively low concentration H2O (75-80%) (Usually 95-98% in bacteria etc.) Therefore can grow on moist and aquatic environments.

  3. Physiology of Fungi 3. pH Normally prefer low pH (produce acid themselves) 4. Oxygen Normally prefer O2 (i.e. aerobic) although some species can tolerate anaerobic conditions temporarily. Aerobic respiration: C6H12O6 6CO2 + 6H2O Anaerobic respiration fermentation: C6H12O6 2C2H5OH + 2 CO2 (Yeasts) 5. Temperature Grow in range 2 - 25oC, optimum = 15oC i.e. psychrophilic - cold-loving

  4. Importance of Fungi in Freshwater 1. Fungi play similar role to bacteria. Very important in breakdown of complex organics to simpler substances for algae (i.e. mineralization) Associated with polluted waters because of high nutrient requirements. 2. Indicators of pollution Fusarium, Leptomitisand Geotrichum associated with a mesosaprobic zone in Saprobian system.

  5. Importance of Fungi in Freshwater 3. Actinomycetes and Fungi Give Taste and Odour problems in treated water. a) Grow on reservoir walls, and release complex organic compounds when dead. (TASTE AND ODOUR). Also grow on dead algae. Very common after algal blooms. Saprophytic b) Grow in cold water systems in buildings, especially where cold and hot water pipes are adjacent. 4. Sewage Fungus growths in rivers receiving certain industrial wastes (e.g. wood pulping and dairy wastes). 5. Marine - rare

  6. Fungi in Aquatic Environment Tolerate • low DO • low pH High C:N ratios. Trade wastes Percolating Filters Leptomitis lacteus(feed channels) Geotrichum 1st surface Fusarium aqueductum colonisers Sepedonium (sub-surface) Activated Sludge Rare, unless trade wastes give Bulking problems e.g. Geotrichum Pullularia pullulans Phoma Sporotrichum

  7. Sewage Fungus WRC Survey of 90 Sewage Fungus Associations thick, slimy growths on river bed pulp mill, dairy or strong sewage Leptomitis lacteus 4% Geotrichum 7% FUNGI Fusarium aqueductum 3% Other fungi 10% Sphaerotilus natans 89% BACTERIA* Zoogloea 94% Stigeoclonium 10% Diatoms 18% ALGAE Ulothrix 4% Sewage Fungus - therefore a misnomer Mainly bacteria

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