CEE 370 Environmental Engineering Principles. Environmental Microbiology

Transcription

1 Updated: 1 October 015 Print version CEE 370 Environmental Engineering Principles Lecture #13 Environmental Biology II Metabolism Reading: Davis & Masten, Chapter 3 David Reckhow CEE 370 L#13 1 Environmental Microbiology Types of Microorganisms Bacteria Viruses Protozoa Rotifers Fungi Metabolism Microbial Disease Microbial Growth David Reckhow CEE 370 L#13 Lecture #13 Dave Reckhow 1

2 Metabolism Biosynthesis (Anabolism) Energy Production (Catabolism) Metabolites (wastes) David Reckhow CEE 370 L#13 3 An overview of metabolism David Reckhow CEE 370 L#13 4 Lecture #13 Dave Reckhow

3 Energy Source Light Chemicals (e.g., glucose) Storage ATP NAD+ Advantages of oxygen as a terminal electron acceptor aerobic anaerobic facultative David Reckhow CEE 370 L#13 5 ATP ~ ~ 7.3 kcal per mole David Reckhow CEE 370 L#13 6 Lecture #13 Dave Reckhow 3

4 Nicotinamide Adenine Dinucleotide David Reckhow CEE 370 L#13 7 Embden-Meyerhof Pathway Glucose ATP ADP Fructose-1,6-diphosphate NAD+ 4 ADP NADH 4 ATP Investment Pay-back Pyruvate Net result: ATPs or 14.6 kcal/mole David Reckhow CEE 370 L#13 8 Lecture #13 Dave Reckhow 4

5 Advantages of Aerobic Systems If we have aerobic metabolism, rather than fermentation, energy from NADH may be harvested NADH + H + 3PO + 3ADP + O NAD+ + 3ATP + H O 4 This gives us 6 more ATPs. Then the pyruvate may be further oxidized to carbon dioxide and water, producing 30 more ATPs. The final tally is 38 ATPs or 77 kcal/mole of glucose. David Reckhow CEE 370 L#13 9 Pathways Generalized view of both aerobic and fermentative pathways Also showing energy transfer ATP NAD David Reckhow CEE 370 L#13 10 Lecture #13 Dave Reckhow 5

6 Metabolic Classification Carbon Source Heterotrophic: other organic matter Autotrophic: inorganic carbon (CO ) Energy Source (electron donor) Chemosynthetic: chemical oxidation Photosynthetic: light energy Terminal Electron Acceptor Aerobic: oxygen Anaerobic: nitrate, sulfate Fermentative: organic compounds David Reckhow CEE 370 L#13 11 Energy Flow Storage of Energy Photosynthesis Release of Energy Respiration Energy transfers by organisms are inherently inefficient 5-50% capture David Reckhow CEE 370 L#13 1 Lecture #13 Dave Reckhow 6

7 Aerobic Respiration A Redox reaction Oxidation of Carbon C( H O H O CO H ) 4 4 Reduction of oxygen or some other terminal electron acceptor O 4H 4e H O e David Reckhow CEE 370 L#13 13 Other TEA: Anaerobic Respiration Nitrate C( H O) NO3 N CO HCO3 H O Manganese 4 C( H O) Mn Mn CO H O Iron 3 C( H O) Fe Fe CO H O Sulfate C( H O) SO4 H S CO H O Fermentation C( H O CH CO ) 4 methanogenesis Ecological Redox Sequence David Reckhow CEE 370 L#13 14 Lecture #13 Dave Reckhow 7

8 Terminal Electron Acceptors Contribution to the oxidation of organic matter Bottom waters of Onondaga Lake, NY (Effler, 1997) Sulfate Reduction 7% Nitrate Reduction 10% Iron Reduction 1% Methanogenesis 3% Aerobic 39% David Reckhow CEE 370 L#13 15 Energetics Principles of Gibbs Free Energy and Energy Balance can be applied to microbial growth David Reckhow CEE 370 L#13 16 Lecture #13 Dave Reckhow 8

9 Energetics Cont. Energy Balance Cell synthesis (R c ) Energy (R a ) Electron acceptor (R d ) R f s R c f e R a R d David Reckhow CEE 370 L#13 17 f-values and Yield Portions of electron donor used for: Synthesis (f s ) Energy (f e ) Values are for rapidly growing cells David Reckhow CEE 370 L#13 18 Lecture #13 Dave Reckhow 9

10 Novel Biotransformations Oxidation Toluene dioxygenase (TDO) David Reckhow CEE 370 L#13 19 Enzyme Chemistry Highly dependent on: Temperature ph David Reckhow CEE 370 L#13 0 Lecture #13 Dave Reckhow 10

11 Overall Types Carbon Source Heterotrophic Autotrophic Energy Source Chemosynthetic Photosynthetic Photoheterotrophs (rare) Photoautotrophs (primary producers) Chemoheterotrophs (organotrophs) Chemoautotrophs (lithotrophs) Purple and green nonsulfur bacteria Cyanobacteria, algae & Plants Most bacteria, fungi, protozoa & animals Nitrifying, hydrogen, iron and sulfur bacteria David Reckhow CEE 370 L#13 1 To next lecture David Reckhow CEE 370 L#13 Lecture #13 Dave Reckhow 11