ERT314 BIOREACTOR SYSTEM

CHAPTER 2: BIOLOGICAL SYSTEMS AND MEDIA DESIGN

2.1 Introduction to Biological System

**rheology – the study of the flow of matters, especially in liquid state

Fermentation with fungi Fermentation with bacteria

Oxygen Demand

OTR = Oxygen transfer rate

OUR = Oxygen uptake rate

ionconcentratoxygen actualC

ionconcentratoxygen saturationC*

tcoefficien transfer massoxygen aK

)C*C(aKOTR

L

L

Most organisms reduce the pH during growth.

LET’S RECALL…

e.g: glycoprotein, oligosaccharides, enzyme etc.

E.Coli has a system where the capacity to use these precursors exceed the capasity of intermediary metabolism

2.2.1 Microbial ProcessesA. Design and Formulation of MediaShould consider:

e.g:

e.g: antagonism (Zn+ to Cu2+), synergism (toxic Cu2+ + Cd2+), stimulation (Ca2+ and Mn2+ depends on Zn2+)

requires higher pantothenic acid content in media

Addition of glycine betaine in media for L- amino acid production which has high glucose concentration, acts as an osmotic protectant.

(if more than 10 mM, no antibiotic is synthesized)

(easily altered)

causing

Whereas others, like dried yeast are generally uniform from batch to batch.

General equation for the stoichiometry of growth and product formation

Where yx/s, yp/s and yCO2/s are

= coefficients related to biomasss, product and CO2 formation

= expressed as C mole of biomass, product and CO2 per mole of carbon and energy source (substrate)1yyy s/2cos/ps/x

s

xs/xs/x Yy

s

ps/ps/p Yy

σi = carbon fraction of i (x,p,s)

Yx/s = g dry weight of biomass per g of substrate consumed

Yp/s = g dry weight of product per g of substrate consumed

Constraints: Low reactor rated and productivity Instability of cell lines presents problem not easy

to overcome Danger of microbial contamination Secondary metabolites is often retained in

biomass Plant cells are often shear sensitive In some cases, secondary compounds should be

removed rapidlyHow to overcome?

,

Some of the important products which are produced from animal cell cultures are :

(i)enzymes (asperagenase, collagenase, urokinase, pepsin, hyaluronidase, rennin, trypsm, tyrosin hydroxylase),

(ii) hormones (leutinizing hormone, follicle stimulating hormone, chorionic hormone and erythropoietin), (iii) vaccines (foot and mouth disease vaccine, vaccines for influenza, measles and mumps, rubella and rabies),

(iv) monoclonal antibodies etc.

Products Application Erythropoietins

Erythropoietin-a Anaemia resulting from cancer and chemothcraoy Erythropoietin-p Anaemia secondary to kindney disease

Human growth hormones hGH Human growth deficiency in children, renal cell carcinoma

Somatotropin Chronic renal insufficiency, Turners' syndrom Monoclonal antibodies (therapeutic)

Anti-lipopolysacharide Treatment of sepsis Murine anti-idiotype/human

B-cell lymphoma B-cell lymphoma Monoclonal antibodies (diagnostics)

Anti-fibrin 99 Blood clot 99 Tcm-FAb (breast) Blood cancer PR-356CYT-356-in-lll Prostate adinocarcinoma

Plasminogen activator Urokinase type plasminogen activator Acute myocardial infarction, acute stroke, pulmonary

embolism, deep vein thrombosis Tissue type plasminogen activator

Recombinant plasminogen activator

Vaccines HIV vaccines (gpl20) AIDS prophylaxis and treatment

Malaria vaccine Malaria prophylaxis Polio vaccines Poliomyelitis prophylaxis

Some products of medical use derived from animal cell cultures. Source: based on Feichter (1996).

Advantages of serum in culture medium are:

i) serum binds and neutralizes toxins,

(ii) serum contains a complete set of essential growth factors, hormones,

attachment and spreading factors, binding and transport proteins,

(iii) it contains the protease inhibitors,

(iv) it increases the buffering capacity,

(v) it provides trace elements.

Disadvantages of serum in culture medium are:(i) it is not chemically defined and therefore it’s composition varies a lot, (ii) it is sometimes source of contamination by viruses etc.(iii) it increases the difficulties and cost of down stream processing, (iv) it is the most expensive component of the culture medium.

THEREFORE,

(1) Immunisation of a mouse(2) Isolation of B cells from the spleen(3) Cultivation of myeloma cells(4) Fusion of myeloma and B cells

(5) Separation of cell lines(6) Screening of suitable cell lines(7)(a) in vitro or (b) in vivo multiplication

(8) Harvesting

Production of monoclonal antibody (briefly)

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