Applied Biology is very very important for CSIR-NET, GATE, IIT-JAM and other competitive exams in Life Science and Biotechnology.

1. Applied Biology
Microbial Fermentation
CSIR-NET (Life Science) &
Kendrika Academy
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Call @ 08726660111
GATE-Biotechnology

2. INTRODUCTION
Fermentation
• In a biochemical sense it is an energy-generation process in where
organic compounds act as both electron donors and terminal electron
acceptors.
• In general any process for the production of desired product by the
mass culture of a micro-organism.
Industrial Fermentation
• When the fermentation is carried out at large scale to get desirable
products it is known as industrial fermentation.

3. RANGES OF FERMENTATION
PRODUCTS
Microbial cell (Biomass)
Production of Saccharomyces
cerevisiae to be used in the baking
industry
production of microbial cells to be used
as human or animal food (SCP).
SCP
Microbial enzymes
Glucose oxidase (Fruit juice: Oxygen
removal)
Amylase (baking and brewing)
Protease (leather: Dehairing, baiting)
Pectinase (Coffee: bean fermentation and
its concentration)

4. Microbial metabolites
 Solvents (ethanol, butanol, propanol)
 Food products (Cheese, yoghurt, vinegar)
 Antibiotics (Penicillin, streptomycin, erythromycin)
 Vitamins (B12, riboflavin)

5. Transformation reactions
 Steroid biotransformation
Beauveria bassiana was able to transform
3-indolylacetonitrile into 3-methylindole
Biofuel
Bioethanol is the most common biofuel,
accounting for more than 90% of total biofuel
usage.
BIOMASS
PRODUCTION
& HANDLING
BIOMASS
PRETREATMENT
CELLULOSE
ENZYME
PRODUCTION
GLUCOSE
PENTOSE
ETHANOL
ETHANOL
USED AS
BIOFUEL
Act on
enzymes
enzymes
ETHANOL
RECOVERY
HYDROLYSIS
FERMENTATION
FERMENTATION

6. Growth curve for Bacteria
Time
Lag phase Log Phase Stationary
Phase
Death
Phase
NumberofBacteria

7. The Lag Phase
• Preparatory Phase
•Cells increase in size NOT in numbers
• What is Pseudo-lag Phase??

8. The Log phase
• Also known as Exponential phase / Growth
phase/Active phase/Trophophase
• Cells increase in numbers
• The rate of cell division is currently at its
maximum
• All the Primary metabolites are produced in
this phase
What is Balanced growth??

9. The Stationary Phase
• Also known as Idiophase
• NET growth is Zero
• The rate at which new cells are produced
is equal to the rate at which other cells
are dying.
• All the secondary metabolites are
produced in this phase
What are Pseudo-secondary
metabolites??

10. The Stationary Phase (Continue)
• What is Cryptic growth??
• What is Endogenous metabolism??

11. The Death (Decline) Phase
• Very few nutrients are left.
• Many bacteria are poisoned by the
waste produced by such large numbers
•Death also occurs in exponential
manner

12. Production process through fermentation
• Upstream Processing
• Bioreactor
• Downstream Processing

13. Upstream Processing
• Isolation of organisms
• Media Design
• Sterilization

14. Bioreactor

15. Modes of Operation

16. Downstream Processing
In Fermentation Broth….
• Main (Desired) Product
• Byproduct
• Waste product

17. Downstream Processing
• Separation
• Purification
• Waste Treatment

18. Downstream Processing
• Centrifugation
• Filtration
• Chromatography
Etc…………….

19. RAW MATERIALS
UPSTREAM PROCESSES
Inoculum
Preparation
Equipment
Sterilization
Media Formulation
and
Sterilization
BIOREACTOR - FERMENTER
Reaction Kinetics
and Bioactivity
Transport Phenomena
and Fluid Properties
Instrumentation
and Control
DOWNSTREAM PROCESSES
Separation
Recovery and
Purification
Waste Recovery,
Reuse and Treatment
THE BOTTOM LINE
REGULATION ECONOMICS HEALTH AND SAFETY

20. Batch culture: Growth Kinetics
m = m max s
(Ks +s)
mmax
1/2 mmax
Ks = substrate concentration
m= specific growth rate
Residual substrate conc. [s]
m
During log phase growth reaches maximum (max)
After depletion of substrate, growth rate decreases and finally ceases

21. As growth increases biomass increases: during log phase
dx = mx
dt
dx. 1 = m
dt x
x = cell conc (biomass) (mg/m3)
t = incubation time (h)
m = specific growth rate (h-1)
x
dx
dt m =slope
1

22. Beginning of log phase t=0 biomass X0
On integration of equation 1
∫dx = ∫ mx
x
Loge X = mt + K (integration constant)
when t=0
Log X0 = K put this value in equation 2
loge X = mt + loge X0
Loge X –loge X0 = mt
ln X = mt
X0
ln X . 1 = td
X0 m
2
3

23. When t = td
X = 2X0
Then ln X . 1 = td
X0
m
ln 2X0 . 1 = td
X0 m
ln 2 = td
m
0.693 = td
m
m = 0.693
td
m is inversely proportional to td
If td is high m is low and vice versa

24. X0 cells inoculated at time t0
X cells at time t
dx = mx Can be written as
equation 3
dt ln X = mt
X0
ln X –ln X0 = mt
Converting natural log
(log10 X –log10 X0) 2.303 = mt
(log10 X –log10 X0) 2.303 = tt-t0
m
(log10 X –log10 X0) 2.303 = m
tt-t0

25. m = m max s
(Ks +s)
mmax
1/2 mmax
Ks = substrate concentration
m= specific growth rate
Residual substrate conc. [s]
m

26. Continuous culture
Volume added should be volume removed
V working volume of the fermenter: m3
F rate of flow in and out m3h-1
Dilution rate = F/V
F = DV (h-1)
Output of biomass in continuous culture
Rate at which medium passes out of the outflow (flow rate F)
conc of biomass in the outflow (i.e. X)
Output = FX
Since F= DV Output = DVX
Productivity that is output per unit volume
prod = DVX prod = DX
V
Basic principles of continuous culture is
controlled by Dilution rate
Rate of limiting substrate conc not m
Continuous enrichment culture

27. Q. If you start out with a population density of 200 CFU/ml of a bacterium that
divides every 30 minutes, what will the population density be at the end of two
hours, assuming the cells are in the log phase of growth.
A) 800 CFU/ml
B) 24 CFU/ml
C) 3200 CFU/ml
D) 12800 CFU/ml
E) 2004 CFU/ml

28. Q. A microorganism 0 m3 working volume with sucrose as the grogrows in a
continuous ‘chemostat’ culture of 6wth limiting nutrient at dilution rate, D =
0.55 h-1. The steady state biomass concentration is 4.5 Kg dry biomass m-3 and
the residual sucrose concentration is 2.0 Kg m-3. The sucrose concentration in
the incoming feed medium is 10.0 Kg m-3.
What would be the yield Y X/S (Kg biomass/Kg substrate)?
a. 0.562 b. 0.462 c. 0.362 d. 0.162

29. Q. How many bacteria are present after 51 hours if a culture
is inoculated with 1 bacterium? Assume the population
doubles every 3 hours.