Bioreactors Drug Delivery & Tissue Engineering Laboratory Sogang University Hyuncheol Kim, PhD

Bioreactors

Drug Delivery & Tissue Engineering Laboratory

Sogang University

Hyuncheol Kim, PhD

Drug Delivery & Tissue Engineering lab.Sogang University

What is a Bioreactor?

• An apparatus for growing organisms (yeast, bacteria, or

animal cells) under controlled conditions.

• Used in industrial processes to produce pharmaceuti-

cals, vaccines, or antibodies

• Also used to convert raw materials into useful byprod-

ucts such as in the bioconversion of corn into ethanol.


What is a Bioreactor?

• Bioreactors supply a homogeneous (same throughout)

environment by constantly stirring the contents.

• Bioreactors give the cells a controlled environment by

ensuring the same temperature, pH, and oxygen levels.


Types of Bioreactors

• Batch: Media and cells are added to the reactor and it is run until a predeter-

mined set point (i.e. time, concentration). The bioreactor has a constant vol-

ume (the initial volume).

• Fed-Batch: The bioreactor is a batch process in the beginning and after a cer-

tain point a feed input is introduced and the volume of the vessel increases.

• Continuous: The bioreactor starts with an initial volume and media is con-

stantly introduced and product is constantly taken out. The inputs and out-

puts are at the same rate, so the volume always remains the same.


Types of Bioreactors

• Bioreactors come in many different sizes and configurations.

http://www.sartorius.com/biostat_aplus/3d.shtml

http://www.pharmaceutical-technology.com/projects/chugay/index.html


Bioreactor Components

• Bioreactors consist of:– Vessel – Agitator– Sparger– Baffles– Probes

Temperature Dissolved Oxygen pH Pressure Gauge

– Cooling Jacket– Ports for input and output of

material– Condenser – Back Pressure Valve– Inlet Filters and Exhaust Fil-

ters– Valves– Load Cell


Bioreactor - Vessel

• The bioreactor vessel is a container which holds the media and

the cells

• Vessels can be made of glass, stainless steel, or a durable plas-

tic.

• The durable plastic vessels are disposable (single-use).

• All the additional parts of a bioreactor connect to the vessel.

• The top of the vessel is called a head plate. On glass reactors,

most additional parts are located on the head plate.


Bioreacotr - Vessel

Vessel

Head Plate


Bioreactor - Agitator

• An agitator is required to mix the contents in the

vessel to ensure a homogeneous environment.

• Agitators consist of a shaft and impellers.

• Mixing of the bioreactor is crucial in order to supply

nutrients and oxygen to the culture and to maintain a

constant pH and temperature.


Bioreactor - Agitators

• Impellers come in many different shapes and sizes depending on what type of mixing is needed.


Bioreactor - Agitators

Agitator Shaft

Impellers


Bioreactor - Sparger

• The sparger is an apparatus used to introduce gasses

into the vessel.

• Spargers are located at the bottom of the vessel and

consist of a tube with tiny holes for the gas to escape

through into the culture.

• The gas coming out of the sparger helps to aerate and

mix the contents in the vessel, as well as supply oxy-

gen to the cells.


Bioreactor - Sparger

Ring Sparger

Micro Sparger

Openings on Ring Sparger


Bioreactors - Baffles

• Baffles are obstructions on the side of the vessel that

generate turbulence in the flow of the culture.

• Baffles are made out of stainless steel and are welded

to the inside of the vessel.

• Baffles help to mix the culture by creating a more tur-

bulent flow.


Bioreactor - Baffles

BaffleBaffles obstruct the flow in the vessel to help mix the contents.


Bioreactor - Probes

• Bioreactors require probes to monitor the culture in

the vessel.

• The probes are found at different locations on the

vessel: head plate, top probe belt, bottom probe belt.

• Useful probes include temperature, pH, DO (dis-

solved oxygen), and CO2


Bioreactor - Probes

Probe Belt

Probes

Probes on head plate


Bioreactor – Cooling Jacket

• Cells give off heat when growing and dividing.

• To maintain a constant temperature in the reactor, the vessel is

covered by a cooling jacket.

• Coolant (cold water or glycol) flows through the cooling

jacket to regulate the temperature.

• The temperature is controlled by the flow rate of the coolant.


Bioreactor – Cooling Jacket

Stainless Steel Cooling Jacket surrounds the vessel.


Bioreactor - Ports

• Bioreactors require addition ports, where material is either in-

troduced or removed from the vessel.

• Ports are needed to add the media (media port), cells (inocula-

tion port), and nutrients (feed ports).

• Ports are also used for the addition of acid and base for pH

control.

• A sample port is also located on each vessel to remove cul-

ture for off-line investigation.


Bioreactor - Ports

Ports


Bioreactor - Condenser

• A condenser is an apparatus that captures saturated

air leaving the vessel.

• The condenser is cooler than the saturated air allow-

ing it to condense on the surface and return to the ves-

sel as a liquid.

• Condensers help to minimize the loss of material out

of the reactor due to evaporation.


Bioreactor - Condenser


Bioreactor - Filters

• Bioreactors need inlet filters to ensure the gasses en-

tering the vessel are sterile.

• They require exhaust filters to keep the reactor ster-

ile and allow gas to escape to regulate pressure.

• Filters require a filter housing – a stainless steel cab-

inet to hold and sterilize the filter.


Bioreactor - Filters

FilterFilter Housing


Bioreactor – Back Pressure Valve

• A bioreactor must remain under constant pressure; we want the

pressure in the reactor to be higher than the pressure surrounding

it

• Constant pressure helps to ensure sterility of the reactor by keep-

ing microbes out (they are less likely to overcome the pressure

gradient)

• Pressure is added to the reactor by the introduction of air at the

top of the reactor (head space).

• The pressure is regulated using a back pressure valve.


Bioreactor – Back Pressure Valve


Bioreactor - Valves

• Valves are used to control the flow of either gas or liquid

• Bioreactors use many different types of valves.

– Manual Valves – open and close the valves with your hand.

– Pneumatic Valves – automatic valve which opens and closes with the use

of high pressured air (instrument air).

– Steam Lock Valves – (so called “block and bleed valves”) a two valve as-

sembly so you can allow a fluid to flow through a portion of the valve and

then close and use the other portion of the valve to sterilize the valve as-

sembly after use to reduce contamination. These valves can be manual or

pneumatic.


Bioreactor - Valves

• Valves are used at many different locations on the

bioreactor

– Sample valve – where a sample from the bioreactor can be

obtained.

– Harvest valve – location where the tank can be drained for

harvest.

– Ports – contain an automatic steam lock valve, so liquid can

be added to the vessel (the port can be sterilized after use to

prevent contamination)


Bioreactor - Valves

Pneumatic (Automatic) Valve Manual Valve

Steam Lock Valves


Bioreactor – Load Cell

• A load cell is a scale that measures the weight of the

bioreactor.

• The bioreactor sits on a series of load cells that com-

press when weight is added to the vessel.

• The weight of the bioreactor can be correlated to the

volume of liquid in the vessel by using the density of

the cell culture medium.

Weight = Density x Volume


Bioreactor – Load Cell

Compact Com-pression

Load Cells

Spacing of Load Cells


Bioreactor Utilities

• Bioreactors require utilities:• Gasses– Air– Oxygen– Carbon Dioxide– Nitrogen

• Clean Steam - for sterilization of the reactor (condensed clean steam equals WFI (water for injection) that is clean enough to be injected)

• Coolant (cold water or glycol) – for cooling jacket• Instrument Air - to operate pneumatic valves

Thank You

Documents

Bioreactors Drug Delivery & Tissue Engineering Laboratory Sogang University Hyuncheol Kim, PhD