Bài giảng Kỹ thuật phản ứng sinh học: Chương 3 - Bùi Hồng Quân

Bài giảng Kỹ thuật phản ứng sinh học: Chương 3 Động học phản ứng tạo sinh khối, cung cấp cho người học những kiến thức như: Quá trình tạo sinh khối vi sinh vật; Kỹ thuật nuôi cây theo mẻ; Kỹ thuật nuôi cây theo mẻ có bổ sung cơ chất; Phương trình Monod và Động học tạo sinh khối vi sinh vật. Mời các bạn cùng tham khảo!

Chương 3 Động học phản ứng tạo sinh khối

 3.1 Các khái niê ̣m cơ bản

 3.2 Quá trình tạo sinh khói vi sinh va ̣t

 3.3 Kỹ thua ̣t nuo i cáy thêo mể

 3.4 Kỹ thua ̣t nuo i cáy thêo mể có bỏ sungcơ chát

 3.5 Phương trình Monod và Đo ̣ng học tạo sinh khói vi sinh va ̣t

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BIOLOGICAL REACTIONS

•BIOREACTORS

Lab Scale Bioreactor

Industrial Scale Bioreactor

Fermentation Process

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Major Functions of a Bioreactor

1) Provide operation free from

contamination ;

2) Maintain a specific temperature ;

3) Provide adequate mixing and aeration ;

4) Control the pH of the culture;

5) Allow monitoring and/or control of

dissolved oxygen ;

6) Allow feeding of nutrient solutions and

reagents ;

7) Provide access points for inoculation

and sampling;

8) Minimize liquid loss from the vessel;

9) Facilitate the growth of a wide range of

organisms

Ref;(Allman A.R., 1999: Fermentation

Microbiology and Biotechnology)

Biotechnological Processes Of Growing Microorganisms In A Bioreactor

1) Batch culture: microorganisms are inoculated into a fixed volume of medium and as growth takes place nutrients are consumed and products of growth (biomass, metabolites) accumulate

2) Semi-continuous: fed batch-gradual addition of concentrated nutrients so that the culture volume and product amount are increased (e.g industrial production of baker’s yeast);

Perfusion-addition of medium to the culture and withdrawal of an equal volume of used cell-free medium (e.g animal cell cultivations)

3) Continuous: fresh medium is added to the bioreactor at the exponential phase of growth with a corresponding withdrawal of medium and cells Cells will grow at a constant rate under a constant condition

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Biotechnological processes of growing

microorganisms in a bioreactor

by Genentech, Corporate Communication

A Fermenter / Bioreactor And Its Parts

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Single System for Anchorage-Dependent and Suspension Cultures

New Brunswick Scientific Company

1500L-Scale Bioreactors (courtesy of Tanox )

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Batch Culture VS Continuous Culture

Continuous systems: limited to single cell protein,

ethanol productions, and some forms of waste-water

treatment processes

Batch cultivation: the dominant form of industrial usage due to its many advantages

Ref;(Smith J.E, 1998: Biotechnology)

Advantages of Batch Culture VS Continuous Culture

1) Products may be required only in a small quantities at any

given time

2) Market needs may be intermittent

3) Shelf-life of certain products is short

4) High product concentration is required in broth for

optimizing downstream processes

5) Some metabolic products are produced only during the

stationary phase of the growth cycle

6) Instability of some production strains require their regular

renewal

7) Compared to continuous processes, the technical

requirements for batch culture is much easier

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Fermentation Technology

fermenter?

Typical pattern of growth cycle during batch fermentation

I Lag phase

II Acceleration phase III Exponential (logarithmic)

phase

IV Deceleration phase

V Stationary phase

VI Accelerated death phase VII Exponential death phase VIII Survival phase

Cell Growth

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Cell Growth cont

Lag Phase Exponential Growth

Phase

Stationary Phase Death Phase

•Little increase in

cell conc

•Cell adjusting their

new environment,

synthesizing

enzymes & ready to

reproducing

•Cell are dividing at max rate

•Cell able to use the nutrients most

efficiently

•Cell reach a minimum biological space (lack of 1@>

nutrients limits cell growth)

•Net growth = 0

•Fermentation product produce

•Decrease in live cell conc occur

•Results of toxic by-product

Rate Laws

Rate law for the cell growth rate of new cells,

Cells + Substrate More Cells + Product

The most commonly used expression is the Monod equation for exponential growth;

c

g C

s dm g

rate growth

cell

r g 

) ( _

_  1

 specific growth rate s



) /

( _concentrat ion g dm3

cell

C c 

Where,

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Rate Laws cont

Specific cell growth rate can be expressed as,

1



C K

C

s s

s





) ( _

_ _

max_

max



 a specific growth reaction rate s



) /

( tan _

_monod cons t g dm3

the

K s 

) /

( )

(nutrient concentrat ion g dm3

substrate

C s 

Where,

Rate Laws cont

Combine,

1



C K

C

s s

s





Will get,

c

g C

s s

c s

g

C K

C

C r



 max Monod equation for bacterial cell

growth rate

Parameter value for the E.coli

growth on glucose

Ks is small for a numb of different bacteria in which case the rate law reduce to,

1 max  1 3h



3

10 2

.

2 X mol dm

K s  

c

r  max

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