CEE 370 Lecture #9 9/29/2010

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CEE 370En i onmental Enginee ing

Updated: 29 September 2010 Print version

Environmental Engineering Principles

Lecture #9

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Environmental Biology IIMetabolism

Reading: Davis & Masten, Chapter 3

Environmental Microbiology Types of Microorganisms

Bacte ia Bacteria Viruses Protozoa Rotifers Fungi

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Metabolism Microbial Disease Microbial Growth

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Metabolism

Biosynthesis(Anabolism)

EnergyProduction

(Catabolism)

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Metabolites(wastes)

An overview of metabolism

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From: Sawyer, McCarty & Parkin, 1994; also: Sawyer & McCarty, 1978

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Energy

SourceSourceLightChemicals (e.g., glucose)

StorageATPNAD+

Ad t f t i l l t t

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Advantages of oxygen as a terminal electron acceptoraerobicanaerobicfacultative

ATP

~ ~

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7.3 kcal per mole

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Nicotinamide Adenine Dinucleotide

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Embden-Meyerhof PathwayGlucose

2 ATP

Fructose-1,6-diphosphate

2 ATP

2 ADP

4 ADP2 NAD+

InvestmentInvestment

PP b kb k

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2 Pyruvate

4 ATP2 NADHPayPay--backback

Net result: 2 ATPs or 14.6 kcal/mole

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Advantages of Aerobic Systems

If we have aerobic metabolism, rather than fermentation, energy gyfrom NADH may be harvested.

NADH + H + 3 PO + 3ADP + O NAD+ + 3ATP + H O+ 43- 2 212 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 277 kcal/mole of glucose.

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ATPs. The final tally is 38 ATPs or 277 kcal/mole of glucose.

Pathways

Generalized view of both aerobic and fermentative pathways

Also showing t f

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energy transfer ATP NAD

From: Sawyer, McCarty & Parkin, 1994; also: Sawyer & McCarty, 1978

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Metabolic Classification

5Carbon Source5Carbon Source5Heterotrophic: other organic matter5Autotrophic: inorganic carbon (CO2)5Energy Source (electron donor)5Chemosynthetic: chemical oxidation5Photosynthetic: light energy

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y g gy5Terminal Electron Acceptor5Aerobic: oxygen5Anaerobic: nitrate, sulfate5Fermentative: organic compounds

Energy Flow

Storage of Energy Photosynthesis

Release of Energy Respiration

Energy transfers by organisms are

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inherently inefficient 5-50% capture

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Aerobic Respiration A Redox reaction

Oxidation of Carbon

Reduction of oxygen or some other terminal electron acceptor

+ +++ eHCOOHOHC 44)( 222

OHeHO 22 244 ++ +

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22

Other TEA: Anaerobic Respiration Nitrate

OHHCOCONNOOHC )( ++++ Manganese

Iron

S lf t

OHHCOCONNOOHC 232232 )( ++++

OHCOMnMnOHC 2224

2 )( +++ ++

OHCOFeFeOHC 2223

2 )( +++ ++

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Sulfate

FermentationOHCOSHSOOHC 222

242 )( +++

242 )( COCHOHC + Ecological Redox Sequencemethanogenesis

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Terminal Electron Acceptors

Contribution to Ironthe oxidation of

organic matter Bottom waters of

Onondaga Lake, NY

Sulfate Reduction

27%

Iron Reduction

1% Methano-genesis23%

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(Effler, 1997)

Aerobic39%

Nitrate Reduction

10%

Energetics

Principles of Gibbs Free Energy and Energy Balance can be applied to microbial growth

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From: Sawyer, McCarty & Parkin, 1994; also: Sawyer & McCarty, 1978

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Energetics Cont. Energy Balance

Cell synthesis (Rc) Energy (Ra) Electron acceptor

(Rd)

RRfRfR +

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From: Sawyer, McCarty & Parkin, 1994; also: Sawyer & McCarty, 1978

daecs RRfRfR +=

f-values and Yield

Portions of electron donor used for: Synthesis (fs) Energy (fe)

Values are for rapidly growing cells

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rapidly growing cells

From: Sawyer, McCarty & Parkin, 1994; also: Sawyer & McCarty, 1978

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Novel Biotransformations Oxidation

Toluene dioxygenase (TDO)

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From: Sawyer, McCarty & Parkin, 1994; also: Sawyer & McCarty, 1978

Enzyme Chemistry Highly dependent on:

Temperature pH

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From: Sawyer, McCarty & Parkin, 1994; also: Sawyer & McCarty, 1978

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Overall Types

5Carbon Source5Heterotrophic5Autotrophic

5Energy Source5Chemosynthetic

Photoheterotrophs(rare)

Photoautotrophs(primary producers)

Chemoheterotrophs(organotrophs)

h h

Most bacteria, fungi, protozoa & animals

Cyanobacteria, algae & Plants

Purple and green non-sulfur bacteria

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5Photosynthetic Chemoautotrophs(lithotrophs)

Nitrifying, hydrogen , iron and sulfur bacteria

To next lecture

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