L15 - Anaerobic Respiration & Fermentation Topics...

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Unformatted text preview: Anaerobic Respiration & Fermentation Topics Anaerobic Respiration & Fermentation Use of Electron Acceptors other than O 2 Denitrification and Sulfate reduction Energy from Aerobic and Anaerobic Processes Fermentation Fermentation and World Affairs 1 The Important (Exam) Stuff Describe how Paracoccus can respire using O and electron 2 acceptors other than O . 2 Explain the oxidase positive and negative electron transport chains of Paracoccus and the products of anaerobic respiration using nitrate (dissimilatory denitrification). Explain how anaerobic respiration is less energy efficient than aerobic respiration. Explain the reason for fermentation, the different types of fermentation and the diversity of fermentation products. Explain how ethanolacetate fermentation impacted world politics in the past and might do so again. Back to the Map...one more time Glycolysis Krebs Cycle Fermentation ETC O 2 NADH ATP Carbon Flow 2 ELECTRON DONOR (AND PRODUCTS) GLUCOSE CARBON DIOXIDE CATABOLISM CARBON ELECTRONS ENERGY ELECTRON TRANSPORT OXYGEN (O ) WATER (H O) 2 2 ELECTRON ACCEPTOR (AND PRODUCTS) Paracoccus denitrificans + O 2 3 Paracoccus denitrificans + NO 3 ELECTRON DONOR (AND PRODUCTS) GLUCOSE CARBON DIOXIDE CATABOLISM CARBON ELECTRONS ENERGY ELECTRON TRANSPORT Nitrate (NO ) Nitrite (NO ) 3 2 ELECTRON ACCEPTOR (AND PRODUCTS) 4 Denitrification ENZYME Nitrate reductase Nitrite (NO ) 2 Nitrite reductase Nitrous oxide (N O) 2 N O reductase 2 Nitric oxide (NO) NO reductase Nitrogen (N ) 2 2 electrons 2 electrons 2 electrons Nitrate (NO ) 3 2 electrons ELECTRON DONOR (AND PRODUCTS) GLUCOSE CARBON DIOXIDE CATABOLISM CARBON ELECTRONS ENERGY ELECTRON TRANSPORT SULFATE (SO 2 ) 4 HYDROGEN SULFIDE (H S) 2 ELECTRON ACCEPTOR (AND PRODUCTS) 5 Aerobic vs Anaerobic Respiration Denitrification & SulfateReduction are usually dissimilatory processes. Cells reduce large quantities of electron acceptor (more than needed for nutrition!) Lower energy than from using O = lower biomass 2 6 Back to the Map... yet again Glycolysis Krebs Cycle Fermentation ETC NADH ATP Carbon Flow What is Fermentation? Means "to rise" Many types of fermentation Mechanism for regenerating + NAD from NADH without O 2 Organics (pyruvate or derivative) are used as both electron donors and acceptors Type of fermentation is useful for microbial identification Process is found in many organisms, including humans 7 "I would give all my fame for a pot of ale and safety." William Shakespeare (King Henry V) Fermentations 8 Fermentative Diversity Homolactic Fermentation: Only generates lactic acid (lactate) Page 175 EthanolAcetate Fermentation: Other products All use pyruvate, NADH and generate NAD+ Microbiology and World Affairs acetone Unlike yeast, fermenting simple sugars into alcohol and carbon dioxide, Clostridium acetobutylicum can ferment whey, sugar, starch, lignin, cellulose fiber and other biomass directly into acetone, butanol, propionic acid, ether, and glycerin. This fermentation is called: ABE synthesis. 9 100% butanol vehicle butanol molecule Butanol fermented from a biomass source, by Clostridium acetobutylicum, produces no net carbon dioxide. Biobutanol fermentation produces layers less expensive to separate/refine than gasoline or bioethanol. Biobutanol doesn't have to be mixed with gasoline, like bioethanol, and doesn't corrode metal engine parts like bioethanol. Biobutanol does not readily adsorb moisture, like bioethanol, so the engine and fuel system modifications required for ethanolbased fuels are unnecessary. Biobutanol has octane fuel value similar to regular gasoline, unlike bioethanol that would require larger, less efficient, fuel tanks. 100% Butanol can be utilized in standard gasolinepowered vehicle without any modifications, producing mileage performance similar to gasoline without the NxO and Sulfurbased pollutants. Text References Pages 118120, 558560, 574, 578, 958962 th (11 Edition) 10 ...
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This homework help was uploaded on 03/21/2008 for the course PY 211 / 212 taught by Professor Chilton during the Spring '08 term at N.C. State.

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