Pengantar Bioproses Pertemuan 2

1. PENGANTAR BIOPROSES/
INTRODUCTION TO
BIOPROCESS (STK-3229)
Pertemuan 2
Rivaldi Sidabutar, S.T., M.T.
Program Studi S1 Teknik Kimia - Fakultas Teknik

2. Capaian Pembelajaran Mata Kuliah (CPMK)
Setelah mengikuti perkuliahan Pengantar Bioproses ini,
mahasiswa akan mampu mendefinisikan dan
merencanakan konsep bioproses dan aplikasi bioproses
dalam proses Industri dan mampu memahami serta
menggambar kurva pertumbuhan mikroorganisme

3. Sub-CPMK
Sub-CPMK 2:
Mahasiswa akan mampu mengidentifikasi dan menjelaskan
kontrol pertumbuhan dan perbanyakan mikroba dan pengaruh
penambahan kontrol mikroba

4. Objective
1. The control of microbial growth
2. The effect of microbial control agents on cellular
structures
3. Compare effectiveness of moist heat vs dry heat

5. Reference
1. Ketchum, P., Microbiology: Concepts and Application, John Wiley & Sons, New York, 1988.
2. D. Dwijosaputro. Dasar-dasar Mikrobiologi. Penerbit Djambatan 1990.
3. Krueger, et al., Introduction to Microbiology, Mc Millan, 1979.
4. Frosbisher, et al., Fundamental of Microbiology, Saunders (Toppan), 1974
5. Bailey dan Ollis. Biochemical Engineering Fundamentals, Mc Graw Hill, 1987
6. Aiba, et al., Biochemical Engineering, Tokyo University Press, 1973
7. Cooney, Fermentation and Enzyme Technology, John Wiley, 1973
8. Wang, D.C., Cooney, C.L., Dunnill, P., Humphrey, A.E., & Lilly. M.D. Fermentation and Enzyme
Technology. John Wiley & Sons, Singapore, 1979.

6. Schedule and evaluation assessment
Schedule :
• Class A and C : Wed, 1.00 – 2.40 p.m
• Class B and D : Wed, 8.00 – 9.40 a.m
Evaluation assessment
Evaluation Assessment is carried out on each learning achievement with details:
- Problem Based Learning (individual ass)
- Tasks (ind/group)
- CP exam

7. What do you know about
Microbial growth control ?
Short Quiz

8. Control of Microbial Growth : Terminology
 Sepsis: microbial contamination.
 Asepsis: absence of significant contamination.
 Aseptic surgery techniques prevent microbial contamination ofwounds.
 Antimicrobial chemicals,expected to destroy pathogens but not to achieve
sterilization
 Disinfectant: used on objects
 Antiseptic: used on livingtissue

9. . . . More Terminology
 Sterilization: Removal of all microbial life
(heat, filtration)
 For food:Commercial sterilization to kill C.botulinum
endospores
 Sanitization: reduces microbial numbers to safe levels
(e.g.:eating utensils)
 Bacteriostatic: Inhibits bacterial reproduction
 Bactericidal: Kills bacteria
 Fungicide, sporicide, germicide, biocide
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10. Rate of Microbial Death
Microbial Death
Curve, plotted
logarithmically,shows
this constant death
rate as astraight line.
Bacterial populations subjected to heat or antimicrobial chemicals
die at a constant rate.
Rate: 90% / min

11. Physical Methods of Microbial Control
 Heat is veryeffective (fast and cheap).
 Thermal death point (TDP): Lowest temperature at which
all cells in aculture are killed in 10 min.
 Thermal death time (TDT):Time to kill all cells in aculture
 Decimal ReductionTime (DRT):
Minutes to kill
90% of a
population at a
given temperature
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12. Moist Heat Sterilization
⚫Denatures proteins
⚫Autoclave: Steam under pressure
⚫Most dependable sterilization method
⚫Steam must directly contact material to be sterilized.
⚫Pressurized steam reaches higher temperatures.
⚫Normal autoclave conditions:
121.5Cfor 15 min.
⚫Prion destruction: 132C for 4.5 hours
⚫Limitations of the autoclave
12

13. 13
Moist Heat Sterilization

14. Filtration
⚫Air filtration usinghigh efficiencyparticulate
air (HEP
A) filters. Effective to 0.3 m
⚫Membrane filters for fluids.
⚫Pore size for bacteria:0.2 – 0.4 m
⚫Pore size for viruses: 0.01 m
⚫T
ypes of filters: depth, membrane, nucleopore Fig 7.4
14

15.  release as heat to
⚫W
avelength: 1 mm – 1m
⚫H2O quicklyabsorbs energy environment
⚫Indirect killing of bacteria throughheat
NonionizingRadiation: Microwave
Fig 7.5
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16. Chemical Methods of Microbial Control
⚫ Few chemical agents achieve sterility
.
⚫ Consider presence of organic matter, degree of contact with
microorganisms, and temperature
⚫ Disinfectants regulated byEP
A Antiseptics
regulated byFDA
⚫ Use-dilution test
1. Metal rings dipped in test bacteria are dried.
2. Dried cultures ofS.choleraesuis,S.aureus,andP
.aeruginosaare placedin disinfectant for
10 min at 20C.
3. Ringsare transferred to culture media to determine whether bacteria
survived treatment.
16

17. Question
In your opinion,
how do you how do you conduct the kinetics of microbial growth?

18. Kinetics of microbial growth
Fermentation can be conducted through :
1. Batch
2. Continuous
3. Fed-batch processes
The operation depends on the desired product

19. The change in microbial concentration in the exponential phase is
written as follows:
x = x e µ t
t 0
d x = µ x
d t
Where
x : concentration of microbial biomass
t : time (hours)
µ : specific growth rate (hour-1) If the above equation is integrated,
then:
Xo : initial biomass concentration
Xt : biomass concentration after time t
This equation can be changed to :
ln xt = ln xo + µt

20. The Monod equation has two limiting cases:
1. High substrate concentration: S >> Ks
• Under these condition, growth will occur at the
maximum growth rate
2. Low substrate concentration: S << Ks
• This type of growth is typically found in batch flask systems at the
end of the growth curve as the substrate is nearly all consumed.
• It is also the typical growth that happened in the natural environment
where substrate and nutrients are limiting.
dt
m
dx   x
 m
dx  Sx
dt Ks

21. Chemical reactions of microbial growth in a culture medium
+ product
metabolites CO2
H2O
enzyme
Substrate microbe
Source. : carbon
nitrogen
oxygen
Sulfur phosphorus
mineral

22. Calculating yields:
Calculating the economic yield, Yp/x
Yx/s = g/L biomass
g/L carbon substrate used
P / X
g/l the result product
= g / g
g/L biomass formed
Y =
Substrate Microbe Yx/s O2 Demand
(gO2/g dried biomass)
Glucose E.coli 0,53 0,4
C.utilis 0,54 0,6
Methanol.
Pseudomonas
0,54 1,2
Ethanol S.cerevisiae 0,63 2,0
Methane mixed bacterial
culture
0,62-0,99 2,6-4,8
Table of biomass yield and oxygen demand

23. CONCLUSION
1. Type of Sterilization : to sterilize medium and instrument
belongs to mode slow and fast; in commercial plant, vapor
(steam) will pouring to reactor directly; differentiation of
sterilization time according to material of medium
(Meigan)
2. Sterilization is step to sterilization the medium, not the
bacteria; air filtration using HEPA, mebrane and paper
filtration (Marchella)

24. CONCLUSION
1. Control of Microbial Growth : using sterilization autoclave
at 121.5 C with glass material and distilled water; Air
filtration : using HEPA filter or paper filtration using
vacuum pump (Rahel)
2. Heat exchanger to cool down temperature : cooler and
chiller (using freon); mode fermentation : batch, fed batch
and continuous (Alwi)
3. Control of microbial growth : we maintain the growth rate
of contamination to reduce the competency and optimalilty
the fermentation of microbe (Wildan)

25. Next week :
Objective:
1. Extraction process and disruption cells
2. Kinetics of microbial growth for continuous culture
3. Calculate of yield coeficient
4. Application of batch and continuous culture

26. THANK YOU!