+ All Categories
Home > Documents > Bioprocess Control - Universitas...

Bioprocess Control - Universitas...

Date post: 05-Jul-2018
Category:
Upload: vuongdung
View: 230 times
Download: 0 times
Share this document with a friend
21
Bioprocess Control MATA KULIAH: PENGANTAR TEKNOLOGI BIOPROSES Nur Istianah-THP-FTP-UB-2014
Transcript

Bioprocess Control

MATA KULIAH: PENGANTAR TEKNOLOGI BIOPROSES

Nur Istianah-THP-FTP-UB-2014

Successful of bioprocessing depends on controlling key processvariables:

1. Nutrient metabolite concentrations,

2. Growth factor compositions, and

3. Physiological parameters (e.g., temperature, pH, and oxygen)

Nur Istianah-THP-FTP-UB-2014

Bioprocess Parameter

1Nur Istianah-THP-FTP-UB-2014

2Nur Istianah-THP-FTP-UB-2014

They affect cell growth, viability, and differentiation.

A fed-batch strategy is often considered most suitable for

tuning and optimizing cell metabolism. It is more efficient,

which reduces metabolite accumulation in culture

supernatant.

Nutrient metabolite concentrations

3Nur Istianah-THP-FTP-UB-2014

This play a crucial role in regulation of stem cell behavior.

So perfusion mode has been preferentially adopted for

most stem cell bioprocesses because it ensures continuous

renewal of nutrients and other factors as well as

continuous removal of metabolic by-products.

Growth factor compositions

4Nur Istianah-THP-FTP-UB-2014

1. MSC differentiation is enhanced at lower temperatures (32 °C)than in 37 °C conditions (70), whereas high temperatures (39°C) enhanced megakaryopoiesis in CD34-enriched cord bloodcells (71).

2. High pH (7.60) enhanced differentiation and maturation ofmegakaryocyte progenitors (72), whereas lower values (7.1)increased their expansion capacity (73).

3. Oxygen is critical to hESC culture (18), and emerging evidencesuggests that reducing its concentration to low levels (74, 75)can be beneficial for in vitro maintenance of pluripotenthESCs, supporting their self-renewal and reducing spontaneousdifferentiation while maintaining karyotypic integrity (76, 77)compared with normoxia conditions (20%). So a robust strategyhas been developed for mass production of undifferentiatedhESCs using pO2 –controlled bioreactors (61).

Physiological parameters (case study)

Nur Istianah-THP-FTP-UB-2014

Bioprocess Parameter (all)

6

Optimization

Nur Istianah-THP-FTP-UB-2014

For optimized process yields, control system performance iscritical to managing and documentingperfusion, recirculation, and feeding of bioreactor cultures foran optimal growth environment and maximized cell viability.This is particularly important for the dynamic environmentscreated by differentiating stem cells.

7Nur Istianah-THP-FTP-UB-2014

Monitoring and controling

Process

Measure all of variable

Decide which variable relevant

Compare the measured value with the calculated(desired) one

Decide the action of result

8Nur Istianah-THP-FTP-UB-2014

Measurement of variable

2 Using sensor 2 Manual analysis

1. Temperature

2. pH

3. Pressure (PO2, PCO2)

4. CO2, CCO2 (dissolved)

5. Biomass

6. Optical density

7. Redox potential

8. Thermodynamics

1. Cell mass concentration

2. Cell number concentration

3. Substrate

4. Product

5. Intermediet

9Nur Istianah-THP-FTP-UB-2014

Measurement of variable

10Nur Istianah-THP-FTP-UB-2014

Fig. 1. Common measurement and control of bioreactors as generally accepted as routine equipment

Bernhard Sonnleitner, 1999

11Nur Istianah-THP-FTP-UB-2014

Measurement of variable

Taking sample Insitu

measurement

The methods of direct growthmeasurement are cell opticaldensity, total cellcounters, coulter counter, celldry weight, packed cell volumeand optical detectors.

The indirect measurements ofcell growth are based on cellularcomponents, measurements ofATP, bioluminescence, substrateconsumption and productformation, oxygen uptakerate, respiration quotient andheat evolution.

12Nur Istianah-THP-FTP-UB-2014

Basic control fasilities

Temperaturecontrol

pHcontrol

Dissolvedoxygencontrol

Foamingcontrol

Level control

The vessel is jacketed for cooling and heating

Use base, acid or buffer

Rate of oxgygen supply

Antifoam,agitation

Rate of substrate (valve, flow meter)

13Nur Istianah-THP-FTP-UB-2014

Temperaturecontrol Heat is generated in the fermenter by dissipation

of power, resulting in an agitated system; heat isalso generated by the exothermic biochemicalreactions (related to the rate of cell growth).

Measuring temperature: using thermometers/thermocouples/ thermistors/ platinum resistancethermometers/ miniature integrated circuit devices

Controlling: cooling by jacketed system with theprinciple of heat transfer; heat production is equalto the heat transfer by the jacketed system.

14Nur Istianah-THP-FTP-UB-2014

pHcontrol

The pH has a major effect on cell growth and productformation by influencing the breakdown of substrates andtransport of both substrate and product through the cell wall

Measurement of pH is based on the absolute standard of theelectrochemical properties of the standard hydrogen electrode. Ag/AgClelectrode and KCl electrolyte saturated with AgCl2.

A constant potential ismaintained at the inner surfaceof the glass membrane by fillingthe tube of the electrode witha buffered solution ofaccurately determined andstable composition, and withconstant and accurate hydrogenion activity.

15Nur Istianah-THP-FTP-UB-2014

Dissolvedoxygencontrol

Method of DO measurement:

(1)The tubing method;

an inert gas flows through a coil of permeable silicon

rubber tubing, oxygen diffuses from the broth then

measured by an oxygen gas analyser

(3) electrochemical detectors (the most common)

types: galvanic and polarographic detectors

It use membranes to separate electrochemical cell components

from the broth

(2) Use of mass spectrometer probes;priciple: the ability of the gas to diffuse across the surface membrane.

16Nur Istianah-THP-FTP-UB-2014

Exemple of sensoring scheme (PO2)

O2 changes

O2 react with H2O to release electron (make a current)

Current was presented as “PO2”

by termistor

.P x= PO since

POhigher theis O More

2O2

22

17Nur Istianah-THP-FTP-UB-2014

Foamingcontrol

The problems caused by foam are the loss of broth, clogging ofthe exhaust gas system and possible contamination, a problemthat is due to wetting of the gas filters.

Foam breaker: blades or disks operate on the centre of the shaft and generally mounted on the same agitator shaft.

Chemical anti-foams, based on silicon, prevent any foamingby reducing the interfacial tension of the broth. Use ofchemical anti-foam may complicate the microbialfermentation process, and some may act as an inhibitor.

Ultrasonic waves also can be used to destroy the foam.

Measuring foam use foam detector

18Nur Istianah-THP-FTP-UB-2014

Foamingcontrol

19Nur Istianah-THP-FTP-UB-2014

Level control

Rv = resistancce of effluent rate (related to the biomass growth)

Level control is needed for continuous bioreactor.This aimed to maintain its continuity and alsoprevent overflow that causes broth losses

When liquid reach the level detector (sensor), conductancechanges and controller sent information to the inlet andeffluent valve to adjust liquid level by consider this equation:

THANKS FOR YOUR ATTENTION

The best person is one give something useful always

Nur Istianah-THP-FTP-UB-2014


Recommended