Microbes and MetabolismAIM

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.

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 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 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) Prokaryotic heterotrophs and chemolithotrophs motile and non-motile coccoid, rod and filamentous small, typically 1m diameter

Fungi (decomposers) Eukaryotic heterotrophs non-motile filamentous typically 1m to 10m diameter and up to 1000m long

Algae (producers) Eukaryotic phototrophs motile and non-motile unicellular, multicellular, filamentous, branched, complex extremely wide range m to metres.

Classes of Microorganism

Protozoa (decomposers, feeders) Eukaryotic heterotrophs typically motile (nonmotile retain flagella/cilia for feeding) many shapes, some polymorphic range 1m to 2000m predatory, some phototrophic

Metazoa – (feeders) Eukaryotic heterotrophs 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

Sediment Community (decomposers)Guild A - fermentative bacteriaGuild B - methanogenic bacteriaGuild C - sulphate reducing bacteriaGuild D - Denitrifying bacteria

Producer Communityphotosynthetic microbesalgae, cyanobacteria

Decomposer CommunityChemoorganotrophic bacteria

Lake

Sediment

Nutrientcycling

Light

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- , SO4

2- , 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.

NO3- , SO4

2- , 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

CARBON SOURCE

Inorganic CompoundsCO2 HCO3

- CO32-

Organic Compounds

Light

InorganicCpds

OrganicCpds

Purple and greenbacteria. Some algae.(Photoheterotrophs)

Algae, Cyanobacteria and purple/green bacteria.(Photoautotrophs)

Iron, sulphur andnitrifying bacteria.(Chemolithotrophic Autotrophs)

Some sulphur bacteria.(Chemolithotrophicheterotrophsor Mixotrophs)

Most prokaryotes and eukaryotes.( Chemoorganotrophs )

Not known

ENERGY