1. Microbes and Metabolism AIM To gain an understanding of : vThe key microorganisms relevant to Water & Wastewater vThe different mechanisms of energy production and metabolism References vLester JN & Birkett JW (1999): Microbiology and Chemistry for Environmental Scientists and Engineers vMadigan MT, Martinko JM & Parker J (2000): Brock - Biology of Microorganisms vHawker L.E. and Linton A.H.: Microorganisms - Function, Form and Environment

2. Why study the biology of water ? vMicrobiology 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 vWater 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

3. Nomenclature vBiology  the study of living things vZoology  the study of macroscopic vertebrates and invertebrates vBotany  the study of higher plants (Macrophytes) vMicrobiology  the study of microorganisms –Bacteriology - (bacteria) –Mycology - (fungi) –Virology - (viruses) –Protozoology (unicellular animals) –Phycology (unicellular and multicellular algae)

4. Some Biological Fundamentals vCells - specialised (differentiated) vCell Walls - Polymer Reinforcement vMembranes - impermeable barrier, vCytoplasm - internal medium vNucleus - DNA vVacuoles - storage, pressure vRibosomes - protein synthesis (translation) vEnzymes - proteins which catalyse chemical reactions vProteins - Lipids - Carbohydrates

5. 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

6. Classification of Microorganisms vProkaryotes  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 vEukaryotes  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

7. Classification of Organisms vBacteria  Prokaryotic hetertrophs and chemolithotrophs  motile and non-motile, coccoid, rod and filamentous  small, typically 1  m diameter  decomposers vFungi  Eukaryotic heterotrophs  non-motile, filamentous  typically 1  m to 10  m diameter and up to 1000  m long  decomposers, predatory (nematodes) vAlgae  Eukaryotic phototrophs  motile and non-motile, unicellular, multicellular, filamentous, branched, complex  extremely wide range  m to metres.  producers, decomposers

8. vProtozoa  Eukaryotic heterotrophs  typically motile (nonmotile retain flagella / cilia for feeding)  many shapes, some polymorphic  range 1  m to 2000  m  predatory, some phototrophic vMetazoa - Eukaryotic heterotrophs  Rotifera (simple invertebrates)  Nematoda (unsegmented worms)  Annelida (segmented worms)  Insecta –Coleoptera (beetles), Diptera (flies) vHigher Organisms  Amphibia, Fish Classification of Organisms

9. Orders of Magnitude in the Living World 10 -9 10 -8 10 -7 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0 10 1 10 2 millimetres MolecularBiological atoms amino acids virusesbacteriaalgae, fungi light microscope electron microscope 10 -9 10 -8 10 -7 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0 10 1 10 2

10. Metabolic Diversity vAerobic  where the terminal electron acceptor is dioxygen (O 2 ). Most efficient metabolism in terms of energy production. vAnaerobic  where oxidized inorganic species e.g.. NO 3 - and SO 4 2- act as electron acceptors in the absence of oxygen. –obligate anaerobes, facultative anaerobes vFermentation  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 vMaintenance Energy  minimum requirement for staying alive vGrowth Rate  rate at which cell divides  Doubling Time - Turnover Time

11. Metabolism vSubstrate Concentration  Bacteria have high affinity, low K s for substrates.  growth rate K S substrate affinity [S] substrate concentration  better competitors in low substrate environments such as in water treatment. vMetabolic Capability  Can metabolise toxic chemicals Cyanide, THM’s, etc.  Cell physically robust.

12. Metabolic Diversity vAssimilative  metabolic modification of a chemical species for the purpose of its incorporation into cellular components.  e.g. NO 3 -, SO 4 2-, and CO 2 are reduced before being incorporated into proteins and carbohydrates as (-NH 2 ), (-SH), and (-CH 2 ) groups.  occurs in bacteria, fungi, algae and plants vDissimilative  metabolic modification of a chemical species in order to generate energy.  NO 3 -, SO 4 2-, and CO 2 are reduced to NH 3, H 2 S and CH 4 which are then excreted from the cell.  carried out by a relatively small number of bacterial species.

13. Metabolic Diversity vAutotroph  An organism using CO 2 as its source of carbon. vHeterotroph  An organism requiring organic compounds as a carbon source. vPhototroph  An organism utilising light as the source of cell energy (e.g. algae) vChemoorganotroph  Uses organic chemicals as energy sources (electron donor) e.g. most bacteria, all nonphototrophic eukaryotes (e.g. man).  All are Heterotrophs. vChemolithotroph  Uses inorganic chemicals as energy sources (electron donor), as most obtain carbon from CO 2 they are usually Autotrophs  Some Chemolithotrophic bacteria obtain carbon from organic compounds (chemolithotrophic heterotrophs) are termed Mixotrophs.

14. Metabolic Diversity CARBON SOURCE Inorganic Compounds CO 2 HCO 3 - CO 3 2- Organic Compounds ENERGY Light Inorganic Cpds Organic Cpds Purple and green bacteria. Some algae. (Photoheterotrophs) Algae, Cyanobacteria and purple/green bacteria. (Photoautotrophs) Iron, sulphur and nitrifying bacteria. (Chemolithotrophic Autotrophs) Some sulphur bacteria. (Chemolithotrophic heterotrophs or Mixotrophs) Most prokaryotes and eukaryotes. ( Chemoorganotrophs ) Not known

15. Microbial Ecology vIndividuals vPopulations  many of the same species vGuilds  metabolically related microorganisms e.g.. homoacetogenic bacteria vCommunities, Consortia  mixed species, interactions between Guilds vCompetition  rivalry among organisms for a common resource vSymbiosis  physical interaction between species which is positively beneficial to both e.g.. lichens, mycorrhizae, mussels vSyntrophy  cooperation between organisms e.g.. metabolite exchange

16. Examples of Microbial Communities Sediment Methanogenic Community Guild A - hydrolytic bacteria Guild B - fermentative bacteria Guild C - acetogenic bacteria Guild D - methanogenic bacteria Producer Community photosynthetic microbes algae, cyanobacteria Heterotrophic Community Chemoorganotrophic bacteria Lake Sediment Carbon and nutrient inputs Carbon and nutrient cycling nutrients