Aquatic Bacteria & Fungi Objective To know the main cellular features, physiology and function of bacteria & fungi in water and wastewater environments To know the species interactions in anaerobic digestion to understand how substrate conditions and nutritional requirements determine the competitive success of these microbes in pollutant degradation processes. References Gray N.F. Biology of Wastewater Treatment Lester J.N. & Birkett J.W. Microbiology and Chemistry for Environmental Scientists & Engineers Madigan M.T., Martinko J.M., Parker J. Brock - Biology of Microorganisms Stanier R.Y. General Microbiology Kiely G Environmental Engineering Lecture Outline Bacteria - Cell Structure Physiology & Function Fungi- Cell Structure Physiology & Function
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Aquatic Bacteria & Fungi vObjective To know the main cellular features, physiology and function of bacteria & fungi in water and wastewater environments.
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Aquatic Bacteria & Fungi
Objective
To know the main cellular features, physiology and function of bacteria & fungi in water and wastewater environments
To know the species interactions in anaerobic digestion
to understand how substrate conditions and nutritional requirements determine the competitive success of these microbes in pollutant degradation processes.
References Gray N.F. Biology of Wastewater Treatment Lester J.N. & Birkett J.W. Microbiology and Chemistry for
Environmental Scientists & Engineers Madigan M.T., Martinko J.M., Parker J. Brock - Biology of
Microorganisms Stanier R.Y. General Microbiology Kiely G Environmental Engineering
Lecture Outline Bacteria - Cell Structure Physiology & Function Fungi- Cell Structure Physiology & Function
Bacteria
What are they? Prokaryotic organisms Bacteria (eubacteria), Archaea (archaebacteria)
Importance in Environmental Engineering Biodegradation Nutrient Cycling Pathogens in Contaminated Waters
Bacterial Cell Structure
Size smallest living organisms, 1m.
Shape typically cocci or rods (bacilli), spiral, stalked, filamentous. multicellular swarms (gliding myxobacteria, myxococcus)
DNA circular, supercoiled, no nuclear membrane. Extranuclear DNA or Plasmids.
Reproduction Asexual = Binary fission, Conjugation via Pili.
Cell Structure
Cell Wall Two types, Gram Positive, Gram Negative Both have Peptidoglycan Gram Negatives also have Lipopolysaccharide (LPS)
Archaea similar to G+ve, have pseudopeptidoglycan
Cell Structure Flagellum
May be present - Motile Polar or peritricious Driven by Proton motive Force (PMF) Chemotaxis - tumble frequency increases.
Cytoplasm complex subcellular organelles usually absent. vesicular and lamellar structures (mesosomes) form by
invagination of cytoplasmic membrane (e.g. N-fixing, Nitrifying, and Phototrophic bacteria).
cytoplasmic membrane essential (maintains PMF). Ribosomes - Protein synthesis Enzymes - metabolism Granules (Inclusions) Gas Vesicles (buoyancy, e.g. cyanobacteria)
Natural Waters Energy source (depends on metabolism and dissolved species)
Cellular Nutrient Requirements C, H, O, N, P, S. vitamins, growth factors, trace elements. Dissolved Gases (O2, CO2, H2S) Nitrogen is usually limiting in oligotrophic waters.
Origin of Nutrients Algal secretions, death. Zooplankton feeding, death. Soil run-off discharge of treated (& untreated) effluents.
Bacteria in Aquatic Environments
Planktonic suspended free cells vertical movement
– O2
– stratified nutrients (in anoxic zone)
Particulate associated with POM
Biofilms surfaces of stones and plants (epiphytic) can be slow growing, psychrophilic environments.
Methanogenesis
Methanogenic Bacteria (Archaea) Chemolithotrophic (autotrophs) H2 and CO2
e.g. Methanobacterium, Methanococcus, Methanospirillum
4H2 + H+ + HCO3- CH4 + 3H2O
Energy -136kJ (but as low concentrations = -30kJ)
Low pE (anaerobic) environments Inhibited in Marine sediments Other substrates include Acetate, Methanol, Formate etc.
Complex polymers
Monomers
Acetate
H2 + CO2Acetate
AcetateH2 + CO2
PropionateButyrateAlcohols
METHANE
Hydrolysis
Fermentation
Acetogenesis Syntrophs Fermentation
MethanogensAcetoclastic
MethanogensH2-Utilising, Acetoclastic
Sugars, amino acids
Protein, Cellulose
METHANOGENESIS
Methanogenesis
Methanogenesis involves Co-operation Inter-species Hydrogen transfer Several Steps from a complex substrate (Cellulose)1. Hydrolysis (depolymerisation) to cellobiose (G-G)2. Fermentation of Glucose to Fatty acids, H2 and
CO2
3. Fatty acids oxidised to H2 and CO2 (SYNTROPHS)
4. Methanogens produce CH4
Syntrophs require H2 to be consumed Typically H2 < 10-4 M
Fungal Cells Size
Typically 5m diameter filament, variable length
Structure Filamentous – hyphae bundled as Mycelia (moulds)Usually branched Rods (Yeasts ) Chitin and cellulose cell walls
DNA chromosomes, nuclear membrane.
Reproduction Asexual = tip cell, sexual = spores called conidia.
Physiology of Fungi
No chlorophyll, produce extra-cellular enzymes. Heterotrophic nutrition. Parasitic or Saprophytic Very slow rate of growth cf. bacteria. Tolerate low DO, low
pH, High C:Nratios. Dairy & Trade wastes
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