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

Physiology of Fungi

No chlorophyll therefore produce extra-cellular enzymes.Heterotrophic nutrition. Parasitic or SaprophyticVery 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.

Physiology of Fungi

3. pH Normally prefer low pH (produce acid themselves)

4. OxygenNormally 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

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, Leptomitis and Geotrichum associated with a mesosaprobic zone in Saprobian system.

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 wherecold 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

Fungi in Aquatic EnvironmentTolerate low DO low pH High C:N ratios. Trade wastes

Percolating Filters Leptomitis lacteus (feed channels)Geotrichum 1st surfaceFusarium aqueductum colonisersSepedonium (sub-surface)

Activated Sludge Rare, unless trade wastes give Bulking problems e.g.GeotrichumPullularia pullulansPhomaSporotrichum

Sewage Fungus

WRC Survey of 90 Sewage Fungus Associationsthick, slimy growths on river bed pulp mill, dairy or strong sewage

Leptomitis lacteus 4% Geotrichum 7% FUNGIFusarium aqueductum 3% Other fungi 10%

Sphaerotilus natans 89% BACTERIA*Zoogloea 94%

Stigeoclonium 10% Diatoms 18% ALGAEUlothrix 4%

Sewage Fungus - therefore a misnomer Mainly bacteria