Transcript Groups of Organisms and their Interactions

Microbes and Metabolism
AIM
To gain an understanding of the following:
 The Key Microorganisms in Environmental Engineering
 The different mechanisms of energy production and metabolism
References
 Kiely G (1996): Environmental Engineering
 Lester JN & Birkett JW (1999): Microbiology and Chemistry for Environmental
Scientists and Engineers
 Madigan MT, Martinko JM & Parker J (2000):
Brock - Biology of Microorganisms
 Hawker L.E. and Linton A.H.: Microorganisms - Function, Form and Environment
Why study Water Microbiology ?
 Microbiology is Fundamental to many Wastewater Treatment processes.
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Carbon oxidation
Nutrient Removal
Solids Removal
Optimisation of performance
Stability of system to perturbations
– flow
– influent composition
 New Processes
 Water Supply  Safety and Quality - Pathogens
– Bacterial - Vibrio cholera, Salmonella typhi, Legionella pneumophila
– Viral - Hepatitis A, Coxsackievirus A & B, Enterovirus
– Protozoan - Entamoeba histolytica, Giardia lamblia
– Helminths
– tapeworm Taenia saginata
– roundworm Ascaris
– Toxins - cyanobacterial blooms
Nomenclature
 Biology
 the study of living things
 Zoology
 the study of macroscopic vertebrates and invertebrate
 Botany
 the study of higher plants (Macrophytes)
 Microbiology
 the study of microorganisms
– Bacteriology - (bacteria)
– Mycology - (fungi)
– Virology - (viruses)
– Protozoology (unicellular animals)
– Phycology (unicellular and multicellular algae)
Classification of Organisms
 Prokaryotes
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DNA present as a single chromosome
Only small amounts of protein associated with the DNA
have few or no membranes within the cell
Do not have a nucear membrane
e.g. Bacteria
 Eukaryotes
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DNA present as multiple chromosomes
Chromosomes associates with large amounts of protein
the cytoplasm contains membranes which can be structured (organelles)
Have a nuclear membrane (DNA visible as a nucleus)
e.g. Yeasts, Fungi, all higher organisms
Classes of Microorganism
 Bacteria (decomposers)
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Prokaryotic heterotrophs and chemolithotrophs
motile and non-motile
coccoid, rod and filamentous
small, typically 1mm diameter
 Fungi (decomposers)
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Eukaryotic heterotrophs
non-motile
filamentous
typically 1mm to 10mm diameter and up to 1000mm long
 Algae (producers)
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Eukaryotic phototrophs
motile and non-motile
unicellular, multicellular, filamentous, branched, complex
extremely wide range mm to metres.
Classes of Microorganism
 Protozoa (decomposers, feeders)
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Eukaryotic heterotrophs
typically motile (nonmotile retain flagella/cilia for feeding)
many shapes, some polymorphic
range 1mm to 2000mm
predatory, some phototrophic
 Metazoa – (feeders)
 Eukaryotic heterotrophs
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Rotifera (simple invertebrates)
Nematoda (unsegmented worms)
Annelida (segmented worms)
Insecta
– Coleoptera (beetles)
– Diptera (flies)
 Higher Organisms
 Amphibia
 Fish
Some Biological Fundamentals
 Definition if ‘LIVING’
 Movement
– usually visible, plant cells, trophism
 Responsiveness
– react to stimuli
 Growth
– increase in mass
 Feeding
– active uptake of new ‘building blocks’ and energy.
 Respiration
– metabolic release of energy
 Excretion
– efflux of waste products
 Reproduction
– new generations of similar organisms
Some Biological Fundamentals
 Cells - specialised (differentiated)
 Cell Walls - Polymer Reinforcement
 Membranes - impermeable barrier
 Cytoplasm - internal medium
 Nucleus – DNA, RNA
 Vacuoles - storage, pressure
 Ribosomes - protein synthesis (translation)
 Enzymes - proteins that catalyse biochemical reactions
 Proteins - Lipids - Carbohydrates
Microbial Interactions
 Ecosystem
 stable association of biological, physical, and chemical components
 Environment
 everything surrounding a living organism
 Microenvironment
 the immediate environmental surroundings
 Habitat
 location in nature where an organism resides
 Niche
 specific conditions of pH, light, water, temperature etc within a habitat which favour a
particular organism
Microbial Ecology
 Individuals
 single cell
 Populations
 many individuals of the same species
 Guilds
 metabolically related microorganisms e.g.. homoacetogenic bacteria
 Communities , Consortia
 mixed species, interactions between Guilds
 Competition
 rivalry among organisms for a common resource
 Symbiosis
 an interaction between species which is positively beneficial to both e.g.. lichens,
mycorrhizae, mussels
 Syntrophy
 cooperation between organisms e.g.. metabolite exchange
Microbial Communities
Light
Producer Community
photosynthetic microbes
algae, cyanobacteria
Decomposer Community
Chemoorganotrophic bacteria
Sediment Community (decomposers)
Guild A - fermentative bacteria
Guild B - methanogenic bacteria
Guild C - sulphate reducing bacteria
Guild D - Denitrifying bacteria
Lake
Nutrient
cycling
Sediment
Metabolic Diversity
 Aerobic
 dioxygen (O2 ) is terminal electron acceptor.Most efficient type of metabolism
 Anoxic
 oxidized inorganic species e.g.. NO3- and SO42- act as electron acceptors (NO oxygen)
 Anaerobic
 Carbon dioxide is terminal electron acceptor
– obligate anaerobes
– facultative anaerobes
 Fermentation
 metabolism of organic compounds without the requirement for external electron acceptors
 energy derived from substrate-level phosphorylation
 low efficiency with incomplete metabolism of substrate e.g. glucose to ethanol
 Maintenance Energy
 minimum requirement for staying alive
 Growth Rate
 rate at which cell divides
Metabolic Diversity
 Assimilative
 metabolic modification of a chemical species for the purpose of its incorporation into
cellular components.
 e.g. NO3- , SO42- , and CO2 are reduced before being incorporated into proteins and
carbohydrates as (-NH2), (-SH), and (-CH2) groups.
 occurs in bacteria, fungi, algae and plants
 Dissimilative
 metabolic modification of a chemical species in order to generate energy.
2 NO3 , SO4 , and CO2 are reduced to NH3 , H2S and CH4 which are then excreted from
the cell.
 carried out by a relatively few number of bacterial species.
Metabolic Diversity
 Autotroph
 An organism using CO2 as its carbon source.
 Heterotroph
 An organism requiring organic compounds as a carbon source.
 Phototroph
 An organism utilising light as the source of cell energy
(e.g. algae)
 Chemoorganotroph
 Uses organic chemicals as energy sources (electron donor) e.g. most bacteria, all
nonphototrophic eukaryotes (e.g. man).
 All are Heterotrophs.
 Chemolithotroph
 Uses inorganic chemicals as energy sources (electron donor)
 most obtain carbon from CO2 i.e. are Autotrophs
 Some obtain carbon from organic compounds (are chemolithotrophic heterotrophs) also
known as Mixotrophs.
Metabolic Diversity
ENERGY
Organic
Compounds
CARBON SOURCE
Inorganic Compounds
CO2
HCO3-
CO32-
Purple and green
bacteria. Some algae.
(Photoheterotrophs)
Algae, Cyanobacteria
and purple/green bacteria.
(Photoautotrophs)
Inorganic
Cpds
Some sulphur bacteria.
(Chemolithotrophic
heterotrophs
or Mixotrophs)
Iron, sulphur and
nitrifying bacteria.
(Chemolithotrophic
Autotrophs)
Organic
Cpds
Most prokaryotes and
eukaryotes.
( Chemoorganotrophs )
Light
Not known