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Fundamentals of
BiologicalProcesses
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Object Of Presentation
To introduce the important aspectsinvolved in microbial metabolism.
To introduce the principal organismsresponsible for wastewatertreatment.
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Why Biological treatment?
10 x 106L Chemicals
8 x 106L Xenobiotic
1 x 106
L Recalcitrant
0.4 x 106 traded at over 50 tonnes
per year
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Objective of biological treatment:
Coagulate and remove the non-settleable colloidal solids .
Stabilize the organic matter.
Reduce the organic matter.
Remove the nutrients.
In short, stabilize organic matter:
convert organic matter tononbiodegradable form so that it doesnot exert oxygen demand.
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Microbes
Virtually every environmental niche
Extremes of pH and salinity
Extremes of temperature and pressure Without air (Anaerobic)
Growth on many chemical substrates
Attached to surfaces in biofilms Geothermal vents and subterranean
deposits
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MICROBIALMETABOLISM
General nutritional requirements -:
CARBON SUBSTRATE (org. or inorg.)
ELECTRON DONOR
ENERGY SOURCE
Need for molecular oxygen.
Basic elements required-C,O ,N,H, P,S
Inorganic elements: K,Mg,Ca,Fe,Na,Cl
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Role of microbes
-
SINGLEBACTERIUM
2.0mORGANIC
POLLUTANT
AND NUTRIENTS
(C,P,N,O,Fe,S)
GROWTH - CELL DIVISION
INCREASE IN BIOMASS(assimilation)
CO2
evolved
(dissimilation)
O2consumption
Controlled release of energy
Slow Burning!
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Basic growth
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Types of microbes
Depending on the energy and carbon source AUTOTROPHS: microbes requiring inorganic
carbonaceous compounds. HETEROTROPHS: microbes requiring organic
compounds . PHOTOTROPHS: microbes consuming light as energy
source . CHEMOTROPHS: microbes obtaining energy from
oxidation of org. or inorg. Compounds. ORGANOTROPHS: organic compounds as source of
electron. LITHOTROPHS: inorganic compounds as source of
electron. E.g. nitrifying bacteria is an example ofchemolitho-
autotrophs.
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CLASSIFICATION OFMICROORGANISMS
PHOTOAUTOTROPHIC
CHEMOAUTOTROPHIC
AUTOTROPHIC HETEROTROPIC
CHEMOHETEROTROPHIC
PHOTOHETEROTROPHIC
CO2
Organic carbon
INORGANIC ORGANIC
OXIDATIONREDUCTION REACTION
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Microbes
By relationship to oxygen
obligate aerobes: need oxygen, use it asterminal electron acceptor
obligate anaerobes: cannot grow in thepresence of oxygen
facultative anaerobes: under certain
conditions can grow in the absence ofoxygen
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Microbe shrinking
Numbers of ribosomes in a cell are tightly linked togrowth rate: E. coli fast ~ 1,000 E. coli slow ~ 10-100When cell lacks nutrients, it eats its own ribosomesto survive (shrinks) because
ribosomes make up much of all volume.
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Energetics
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Central Metabolism Basically the working in a microbial cell is
more or less like a tower by which energygeneration through a various combination ofsubstrates is detected.
EMP (Glycolysis and TCA /Krebs Cycle).C6
2C3(2ATP,2 NADH,2 pyruvate)(2NADH &
2CO2) 2C2 TCA 4CO2, 6NADH
,2ATP & 2FADH2
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Net Energy
Most of the usable energy is beingconverted to-:
1. 10 Molecules of NADH (two fromglycolysis, two from the transitionstage, and six from the Krebs cycle)
2. 2 molecules of FADH23. 4 Molecules of ATP (net gain is only
of 2ATPs)
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Energetic Contd.
Rg = rate of bacterial growth,mass/unit volume time
Y = max. yield coefficient, mg/mg. rsu = Substrate utilization rate.
Rg= -Yrsu
rsu=-mXS / Y(ks+S)
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Energetics Energetic considerations Yield (Y): how much biomass/specific substrate
can be made Theoretically need 35 mmol ATP/g all biomass,
so 1 mol ATP . 30 g cells. Experimental: Streptococcus faecalis Yglucose = 22 g/mol 2 ATP / glucose
Zymomonas mobilis Yglucose = 8.3 g /mol .1 ATP / glucose ~ 10 g biomass/mol ATP
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Energetics Cont.
/
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Important organisms in w/wtreatment
Bacteria Fungi
Nemotodes
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Important organisms in w/wtreatment
Algae
Important organisms in w w
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Important organisms in w wtreatment
Protozoa Rotifers, ciliates,crustaceans
Stentor Celops
Paramecium
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