Automatic antifoam control system
- World’s smallest antifoam control system with miniature foam detector LAMBDA ANTIFO and subminiaturise syringe pump LAMBDA DOZITO for fermenters
- No additional level sensor probe needed to place into the fermenter vessel
- Prevents overdosing of antifoam agent
Why is it necessary to dose the smallest possible amounts of antifoam agent?
The addition of too high amounts of antifoam agent is usually detrimental for the gas transfer rate in liquid medium. Therefore, USP biotechnologists prefer minimal use of antifoam agents to optimise the oxygenation of liquid culture during aerobe growth and production phase.
Low concentrations or no antifoam agent where the culture broth is needed, helps also their colleagues in DSP.
How does the LAMBDA ANTIFO & DOZITO antifoam system optimize antifoam agent dosing?
The excessive addition of antifoam liquid (antifoam overdose) is avoided by the introduction of a waiting time interval of about 20 seconds after the first antifoam addition. The second addition of antifoam agent is only carried out if the foam has not disappeared during the waiting interval time that has elapsed.
In addition, the antifoam dose can also be controlled by the volume step setting on the LAMBDA DOZITO miniature syringe pump.
How does automatic foam detection work in a fermenter?
For automatic antifoam control, the presence of foam in the fermenter vessel is detected by measurement of the electrical conductivity since foaming causes an increase of electrical conductivity.
Electrical conductivity measured without any additional foam probe!
Fermenter vessels with metal head-plates need an additional expensive foam probe while the whole-glass vessels of LAMBDA MINIFOR fermenters do not need any additional level probe to detect foam:
Instead of an antifoam probe, two ports (one port reaching the medium, one port placed at the maximal accepted foam level) of the LAMBDA MINIFOR laboratory fermenter vessel are used as electrodes. As a consequence, no additional port has to be used for anti-foam detection and control.
Foam detector and antifoam controller LAMBDA ANTIFO
The LAMBDA ANTIFO foam detector and antifoam controller detects the presence of foam based on the measured electrical conductivity and sends the impulsion to the pump, which then adds a small amount of antifoam liquid to the fermentation broth in the reactor vessel.
If the foam signal persists, LAMBDA ANTIFO controls the pump to release a new portion of antifoam agent after twenty seconds.
Controlled addition of antifoam with a LAMBDA DOZITO miniature syringe pump
LAMBDA DOZITO is miniature syringe pump remote controlled by LAMBDA ANTIFO foam detector for the automatic addition of antifoam liquid (into the LAMBDA MINIFOR fermentation vessel.
The dispensing of the antifoam liquid can be set up from one drop to 15 drops in one step.
The LAMBDA DOZITO syringe pump is the smallest laboratory syringe pump on the market, hardly larger than the syringe itself.
A completely new motion principle is used in the LAMBDA DOZITO mini syringe pump (no motors, no electromagnets, no compressed gas and the like). The setup and use of the LAMBDA DOZITO is very easy.
The pump is vertically fixed using a magnetic support, so that it takes only about 10 cm2 foot print. It is very important to spare space around the fermenter vessel.
Applications of automatic antifoam control
Microbiological growth and fermentations are often accompanied by foam formation because of the high foaming tendency of solutions containing biomaterials such as nucleic acids or proteins. Mixed and aerated bioreactor media with high protein concentrations tend to produce increased foaming.
Foam must be kept to a minimum to avoid media loss, clogged breather filters and risk of contamination.
Therefore, the automatic antifoam system is recommended for:
- Cell culture medium with BSA
- Formation of high protein concentration (biotransformation)
- Aerobe fed-batch fermentation with C-feed and high cell density of E. coli or yeast cultures.