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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. 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 1mm diameter Fungi (decomposers) Eukaryotic heterotrophs non-motile filamentous typically 1mm to 10mm diameter and up to 1000mm long Algae (producers) Eukaryotic phototrophs motile and non-motile unicellular, multicellular, filamentous, branched, complex extremely wide range mm to metres. Classes of Microorganism Protozoa (decomposers, feeders) 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 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