Environmental Biotechnology (1)

7/28/2019 Environmental Biotechnology (1)

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Environmental

Biotechnology

Applications of Environmental

Biotechnology

Part I (Introduction)

What is environmental biotechnology?

Applications of environmental biotechnology

Comparison of biotechnological treatment andother methods

Aerobic treatment of wastes

Anaerobic treatment of wastes

Enhancement of biotechnological treatment ofwastes

A little more background!


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What is Environmental

Biotechnology? Environmental biotechnology is a system

of sciences and engineering knowledge

related to the use ofmicroorganisms and

their products in the prevention, treatment,

and monitoring ofenvironmental pollution

through solid, liquid, and gaseous wastes

biotreatment, bioremediation of pollutedenvironments, and biomonitoring of

environmental and treatment processes.

Biotechnological agents

Bacteria

Archaea

Fungi

Algae

Protozoa

Prokaryotic microorganisms

Eukaryotic microorganisms


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Part I (Introduction) What is environmental biotechnology?







Applications

biodegradation of organic matter of

municipal wastewater and

biodegradation/detoxication of hazardoussubstances in industrial wastewater

Substances that are not produced naturally and are

slowly/partially biodegradable are called xenobiotics


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To test the biodegradability of xenobiotics:

mineralization rate

respirometry test

ratio of BOD to COD

spectrum of intermediate products of

biodegradation

BOD: Oxygen used for biological oxidation

COD: Oxygen used for chemical oxidation

Applications

prevention of pollution and restoration of

water quality in reservoirs, lakes and

rivers, coastal area, in aquifers ofgroundwater, and treatment of potable

water

Applications


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To develop biodegradable materials for

environmental sustainability

To produce fuels from biomass and

organic wastes

To reduce toxicity by bioimmobilization of

hazardous substances

Applications










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Comparison

Advantages of biotechnological treatment

Biodegradation or detoxication of a wide

spectrum of hazardous substances by natural

microorganisms

Availability of a wide range of biotechnological

methods for complete destruction of

hazardous wastesA diverse set of conditions that are suitable

for biotechnological methods

Disadvantages of biotechnological

treatment

Nutrients and electron acceptors must be added tointensify the biotreatment

Optimal conditions must be maintained in the

treatment system

There may be unexpected or negative effects of

applied microorganisms

There may be unexpected problems in the

management of the biotechnological system because

of the complexity and high sensitivity of the biological

processes

Comparison


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Main considerations Technically and economically reasonable rate of

biodegradability or detoxication of waste substances

during biotechnological treatment

Large volume of treated wastes

A low concentration of pollutant in water or waste is

preferred

The ability of natural microorganisms to degradewaste substances

Better public acceptance of biotechnological

treatment

Comparison










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Aerobic Treatment of Solid Wastes

Composting

Soil bioremediation

Aerobic Treatment of Liquid Wastes

Cometabolism

Aerobic Treatment of Gaseous Wastes

windrow system

static pile system

in-vessel system

Composting


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Composting

The pre-treatments that can be used in

composting: Mechanical disintegration and separation or

screening to improve bioavailability of substances

Thermal treatment

Washing of waste using water or solution of

surfactants to diminish toxic substances in waste

Chemical pre-treatment by H2O2 or ozone to oxidize

and cleave aromatic rings of hydrocarbons



Composting

Soil bioremediation


Cometabolism



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Aerobic treatment of solid wastes

Soil bioremediation

In situ bioremediation

On-site bioremediation

Ex situ bioremediation

Preventing hazardous substances from dispersing

from the accident site into the environment

is an important task of environmental biotechnology

Bioremidaion


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Bioremediation

In situ On site

Ex situ

Bioremediation


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Composting

Soil bioremediation


Cometabolism


Aerobic Treatment of Liquid

Wastes

packed-bed fixed biofilm reactors

fluidized bed reactors

upflow bed reactors


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Wastewater with low concentrations of


Treatment using granular activated carbon

(GAC) in fluidized-bed reactors

Aerobic Treatment of LiquidWastes

Wastewater with low concentrations of


Co-metabolism


Wastes

Cometabolism refers to the

simultaneous biodegradation

of hazardous organic

substances (which are not

used as a source of energy)

and stereochemically similar

substrates, which serve as a

source of carbon and energy

for microbial cells.


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To intensify the biotreatment of liquid wasteMechanical disintegration/suspension of the particles

and hydrophobic substances to improve the reactingsurface in the suspension and increase the rate ofbiodegradation

Removal from wastewater or concentration ofhazardous substances by different methods

Preliminary oxidation by H2O2 or ozone, or Fentonsreagent to produce active oxygen radicals;preliminary photo-oxidation by UV andelectrochemical oxidation of hazardous substances


Wastes

Aerobic Treatment of wastes


Composting

Soil bioremediation


Cometabolism



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bioscrubbers

Aerobic Treatment of Gaseous

Wastes

ANAEROBIC TREATMENT OF WASTES

anaerobic

facultative anaerobic

microaerophilic

obligate aerobic

Oxygen

c

onsomption

Microorganisms


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The Effect of Oxygen

Group O2 /aerobic No O2/anaerobic

O2 effects

Obligate aerobe Growth No growth Required ; aerobicrespiration

Microaerophile Growth if O2level not too high

No growth Required but levelsbelow 0,2 atm

Obligate

aenaerob

No growth Growth Toxic

Facultative

anaerobe

Growth Growth Not required for growth,but utilized when there

Aerotolerant

anaerobe

Growth Growth Not required and notutilized

ANAEROBIC TREATMENT

Obligate anaerobes produce energy from:

1) fermentation

2) anaerobic respiration

3) anoxygenic (H2S S) or oxygenic (H2O

O2) photosynthesis


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Energetic efficiency

dissimilative iron reduction

dissimilative sulfate-reduction

CO2 respiration

fermentation Energetic

efficiency

of

biodegradation

nitrate respiration

aerobic respiration

ANAEROBIC TREATMENT

Land filling


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A combined anaerobic/aerobicbiotreatment can be more effective than

aerobic or anaerobic treatment alone

Biodegradation of chlorinated aromatic

hydrocarbons including anaerobic

dechlorination and aerobic ring cleavage

Sequential nitrogen removal including aerobic

nitrification and anaerobic denitrification

Reduction of sulfate or Fe(III) with productionof H2S or Fe(II) which are active reagents for

the precipitation of heavy metals, organic

acids, and nutrients

ENHANCEMENT OF

BIOTECHNOLOGICAL

TREATMENT OF WASTES


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Understanding the role of

microorganisms

Microorganisms getenergy and nutrientsfrom chemicals

They grow by breakingdown chemicals intosmaller compounds,nutrients and water

A process calledbiodegradation

With the nutrients andenergy produced morebacteria are formed

Some key factors:

Environmental factors, such as pH,

temperature, and dissolved oxygen

concentration, must be optimized Contaminants and nutrients must be

available for action or assimilation by

microorganisms

Content and activity of essential

microorganisms in the treated waste must

be sufficient for the treatment


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The effect of temperature

Microorganisms have been found growing in allenvironments where there is liquid water regardless of itstemperature

A range of temperature over which it can grow Minimum

Maximum

Optimal

The effect of pH Natural environments

varies

volcanic soil:1-3

plant juices and acid

soils: 3-5 fresh water and sea

water: 7-8

alkaline soils and lakes,

ammonia solutions: 9-

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Three cardinal pointsMinimum pH

Maximum pH

Optimal pH


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The optimum pH may be maintained

physiologically by:

control of organic acid formation in fermentation

prevention of formation of inorganic acids

assimilation of ammonium (to decrease pH), nitrate

(to increase pH), or ammonium nitrate (to neutralize

pH)

addition of pH buffers such as CaCO3 or Fe(OH)3

addition of solutions of KOH, NaOH, NH4OH,

Ca(OH)2, HCl, or H2SO4, automatically, to maintain

the pH of liquid in a stirred reactor

Elements in microbial cells

MacronutrientsElement % of dry

weight

Source Function

Carbon 50 Organic comp.;

CO2

Main constituent of

cellular material

Oxygen 20 H2O; organic

comp.; CO2; O2

Cell constituent; Electron

acceptor in aerobic

respiration

Nitrogen 14 NH3; NO3; organiccomp.; N2

Constituent of amino

acids; nucleic acids;

coenzymes

Hydrogen 8 H2O; organic

comp.; H2

Constituent of organic

comp.; energy generation

as protons

Phosphorus 3 Inorganic

phosphates (PO4)

Constituent of nucleic

acids; phospholipids

Cell Biomass: CH1.8O0.5N0.2


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Elements in microbial cells

MicronutrientsElement % of dry

weight

Source Function

Sulfur 1 SO4; H2S; S0;

organic sulfur

Some amino acids (cysteine,

methionine)

Several coenzymes

Potassium 1 Potassium salts Main cellular inorganic cationand cofactor for certain

enzymes

Magnesium 0,5 Magnesium

salts

Inorganic cellular cation;

cofactor for certain enzymatic

reactions

Calcium 0,5 Calcium salts Inorganic cellular cation;cofactor for enzymes;

component of endospores

Iron 0,2 Iron salts Component of cytochromesand other proteins; cofactor for

enzymatic reactions

Trace elements and

Growth factors

Trace elements Small amounts are necessary

Cofactors for a few enzymes Mostly metal ions

Growth factors Pre-made organic compounds

Necessary for growth but the microbe is unable tosynthesize them itself Vitamins

Amino acids


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Addit ion of microorganisms (inoculum) to start

up or to accelerate a biotreatment process

If microorganisms, that are necessary for hazardous

waste treatment, are absent or their concentration is

low in the waste

If the rate of bioremediation performed by indigenous

microorganisms is not sufficient

If the acclimation period is too long

To direct the biotreatment to the best pathway from

many possible pathways

To prevent growth and dispersion in waste treatment

system of unwanted or non-determined microbial

strains


Raw materials(food)

Metabolites(chemicals &Biopolymers)

New cells

Microorganism


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The major difference between

environmental biotechnology and otherdisciplines that feature biotechnology:

Environmental applications are concerned with

mixed cultures and open, nonsterile systems.

Success depends on

how individual microorganisms with desired

characteristics can survive

how desired functions can be maintained in complex

ecosystems how the survival and proliferation of undesired

microorganisms can be prevented.

Microbiology

A basic biological science

Provides tools for investigating theprocesses of life

An applied biological science

Microbiology deals with many importantpractical problems in Medicine

Agriculture

Industry


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Microorganisms as cells Cells are capable of

growth and reproduction

Cells are highlyorganized and selectivelyrestrict what crosses theirboundaries

Cells are composed ofmajor elements (C, N, 0,and S, in particular) that

are chemically reduced Cells are self-feeding

Microorganisms as cells

The cell has a highly organized structure

Macromolecules Proteins

Nucleic acids

Lipids Polysaccharides

Key structures Cell membrane

Cell wall

Cytoplasm

Chromosome

Ribosomes

EnzymesProkaryotic cell


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The phylogenetic tree

Geological and evolutionary timetable


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Cell structure and evolutionary

history

Prokaryotic cell

Eukaryotic cell

Size comparisons

VirusesProkaryotes

Eukaryotes


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Important groups Molds

Aerobic organisms that utilize organic compounds Important roll in biodegradation of organic materials particularly in soil

Yeasts Can grow anaerobically through fermentation

Fermentations in environments high in sugars

Algae Autotrophs (use CO2 as a source of carbon)

Photosynthesis similar to plants

Cyanobacteria

Photosynthesis Protozoans

Heterotrophs that have to catch or trap their food

Developed elaborate mechanisms for movement

Their food usually bacterial cells

Nutritional classification

Auto trophs

Energy source Carbon source Name Example

Light Inorganic Photoautotroph Most photosynteticbacteria

Chromatium /anaerob

Cyanobacteria /aerob

Inorganic Inorganic Chemoautotroph/Lithotroph

Nitrobacter

Organic Inorganic Chemoorganotrophic autotroph

Pseudomonas oxalaticus

Heterotrophs

Light Organic Photoheterotroph Purple and greenphotosynthetic bacteria

Rhodospirillum

Inorganic Organic Chemolithotrophicheterotroph

Desulphovibrio

Organic Organic Chemoorganotrophic heterotroph

E. coli


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Oxygenic phototrophs

Phototrophs

Anoxygenic phototrophs

Those that use water and convert it photochemically

into oxygen and hydrogen, the electron source.

They extract electrons from reduced sulfur compounds,

such as H2S or elemental sulfur; H2; or organiccompounds, such as succinate or butyrate.

Energy and reducing power synthesis in anoxygenic phototrophs. Anoxygenic

phototrophs obtain their energy from light (hv).


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Energy and reducing power synthesis in oxygenic phototrophs. In oxygenicphototrophs, light also drives the oxidation of water to oxygen.

The Oxygen cycle

Oxygenic (plant) photosynthesis CO2 + H2O-----------------> CH2O (organic material) + O2

Aerobic respiration CH2O + O2-----------------> CO2 + H2O


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Enzymes

ENERGY CAPTURE

Electron carriers

Those that are freely diffusible

throughout the cell's cytoplasm

Those that are attached to enzymes

in the cytoplasmic membrane

NAD+ NADP+


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ELECTRON AND ENERGY CARRIERS


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ELECTRON AND ENERGY

CARRIERS

If oxygen is the terminal electron acceptor

ENERGY CAPTURE

How energy is captured? It is

accomplished by transferring the energy

from intermediate electron carriers toenergy carriers.


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How many ATPs can be formed from NADH

under anaerobic conditions?

The energy available in the latter cases is too lowto produce even one mole of ATP per mole ofNADH!!!!!!

http://www.stolaf.edu/people/giannini/flashanimat/metabolism/mido%20e%20transport.swf


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Transfer of energy from energy generation to cell synthesis or maintenance via

an energy carrier, represented by AfP.

METABOLISM

Metabolism is the sum totalof all the chemical processes of

the cell. In can be separated

into:

1-Catabolism , which is all theprocesses involved in the

oxidation of substrates or use of

sunlight in order to obtain

energy, and

2-Anabolism , which includesall processes for the synthesis

of cellular components from

carbon sources.


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The three general

stages ofcatabolism

of fats, carbohydrates,

and proteins under

aerobic conditions.

Reversing the

processes gives

anabolism.

The Carbon cycle Autotrophy

CO2 + H2O----------------->CH2O (organic material)

Heterotrophy CH2O + O2----------------->

CO2 + H2O

The overall process ofbiodegradation depolymerization

polymers (e.g. cellulose)---------->monomers (e.g. glucose)

fermentation

monomers----------------->organic acids (e.g. lactic acid,acetic acid, propionic acid) +CO2 + H2

aerobic respiration

monomers + O2 ----------------->CO2 + H2O


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The carbon cycle and key groups of organisms CO2 fixation

Fermentation and aerobic respiration

Methanogenesis and methanogenic archaea

Methane oxidation and methylotrophic bacteria

Metabolic

diversity

Nitrogen fixation N2 ----------------> 2 NH3 (Rhizobium)

Denitrification / anaerobic respiration NO3 ----------------> NO2 ----------------> N2 (Pseudomonas)

Nitrification NH3 ----------------> NO2 (Nitrosomonas)

NO2 ----------------> NO3 (Nitrobacter)

The Nitrogen

cycle

Aerob process!

Anaerob process!


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Environmental

Biotechnology

Waste Water Treatment

Outline

Background

Sources and characteristics of wastewaters

Wastewater treatment processes


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Background

Water is absolutely essential for theexistence of life

Clean water is a limited source of which

we must take care

The water cycle

Rain/snow

precipitation

Surface runoff Surface water

Infiltration/ percolation

Groundwater

Evaporation

Evapotranspiration

http://www.usgcrp.gov/usgcrp/images/ocp2003/ocpfy2003-fig5-1.htm


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Water cycle in society Water is used mainly for three purposes in our society

Agriculture

Industry and

Domestic use

Huge amount of waste water are produced every day

Nature itself has ability to handle small amounts ofpollutants in water

But we still need waste water treatment plants, otherwisethe natural system would be completely overloaded

Water cycle in society


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Water cycle in municipalities

Water from the water stores

Drinking water

House hold

Industry

WWTP / industry

WWTP

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Environmental Biotechnology (1)