Minifor — operating instructions

Fermentor / Fermenter operating instructions in PDF format


1.1 Introduction

The preparation consists of the calibration of the probes and definition of the initial conditions Connect the line cord at the back of the fermenter and plug it into the power line (90—240 V / 50—60 Hz). Switch on the fermenter. The LED on the front panel is yellow. The display shows the last entered parameters.


Figure 1: control panel
Modes: Function keys: Arrow Keys:

The cursor will be deactivated automatically if no manipulation of the number keys or arrows has been effectuated during 15 seconds.

Number Keys:

Are used for setting of numerical values of parameters (if no cursor is displayed the number keys are blocked, preventing inputs by mistake).

Input modification

Place the cursor on the desired parameter. Enter the value with the number keys. The values are entered without decimal point. For example, 9.00 is entered as 900. The left arrow allows correction of the actual value, the other arrows save the entered value.

Input modification is always the same, independently of the operation mode of the fermenter.

1.2 Probe calibration (gauging pH-probe)

It is important that the sequence as described above is observed exactly! If not, the calibration has not been effectuated properly and has to be repeated.

By pressing key "R" the fermenter switches to the Standby mode, and anew pressing of key "R" sets the fermenter to the Operation mode.


OK — calibration successful
err0 — same gauging solution used twice
err1 — same value entered twice

1.3 Setting the temperature

Move the cursor with the arrows on the field for the temperature setting (SET °C, second row, first column). Enter the desired temperature (the value shown on the first line and first column corresponds to the measured temperature and cannot be changed).

Move the cursor on the field of temperature minimum (ALARM LOW). Enter the desired value. If the temperature falls below this value, an alarm is activated and at the exceeded value an asterisk is displayed.

Move the cursor on the field of temperature maximum (ALARM HIGH). Enter the desired value. If the temperature exceeds this value, an alarm is activated and the exceeded value is highlighted on the display.

1.4 Setting of the other parameters

The remaining parameters are set analogically to the temperature.


1.5 Regulation of pO2

The concentration of dissolved oxygen (pO2) can be regulated by the airflow. This regulation is activated by entering a value for pO2 into the field of the desired pO2 value. The symbol "X" appears on the display at the location of the desired airflow to point out that the airflow is determined by the pO2. The measured airflow value is shown and corresponding alarms (ALARM HIGH, ALARM LOW) can be set. To return to the airflow regulating mode, move the cursor on the field of the airflow and enter the desired value. The symbol "X" is now displayed at the location of the set pO2.

1.6 Calibration of the probes

Calibration of the pH-probe

v. 1. Calibration (Chapter 1.2)

Calibration of the pO2-probe

v. 1. Calibration (Chapter 1.2)

For the 0%-level the gauging solution is a 5% aqueous solution of Na2SO3 (first gauging solution). For the 100%-level, oxygen-saturated water by air is used (second gauging solution).

Calibration of the X-channel

v. 1. Calibration (Chapter 1.2)

Temperature probe, flow meter and the mixing frequency cannot be calibrated. Their actual values are guaranteed and controlled electronically.

1.7 START/STOP-Key "R"

START/STOP- or STANDBY-Key "R" activates and deactivates regulation and alarms. The measured values are not influenced thereby and the actual values are displayed. This is helpful during calibration of the probes and the preparation of the fermenter. In standby mode the LED is yellow. In operation mode it is green.

1.8 PC-Connection

The PC is connected at the back of the fermenter with a DB 9 connector. The different fermentation parameters can be modified from the PC. A Windows compatible program (FNet) is available. It enables data acquisition and real-time visualisation of the different parameters.


2.1 Preparation of the vessel

2.1.1 Mounting of the vibration mixer

The disassembled head is shown in figure 2.

Figure 2Figure 3

Slide the mobile part of the cock head 2b into the corpus of the cock head 2c (figure 3).

2.1.2 Air inflow

A silicone tube of 5 mm diameter and 1 mm wall thickness is used for the air inflow. The tube is put through the tubular jacket 9j. A doubly conical insert 9i is placed into the tube end. A black tube is placed on this jacket 2d (it can be omitted). This assembly is screwed deeply into the mobile part of the cock head (figure 4). A convenient air input filter is fixed on the other end of the tubing and secured in place with a clamp (figure 10).

Figure 4Figure 5

Place the membrane 2a on the lower side of the cock head and screw the axis of the mixer on the mobile part of the cock head (figure 5).

This membrane guarantees the sterility and must be faultless and well mounted!

Figure 6Figure 9Figure 10
Figure 8

The mixing disc is positioned on the axis, about 1 cm from the end, and tightened by the socket head screw (figure 6). The gas distributor is screwed onto the axis with a socket head screw (figure 7).

The gassing holes can be cleaned with a wire if necessary.

The head is tightly screwed onto the fermenter vessel with nut 8h (figure 8).

For mounting, it is advantageous to fix the fermenter vessel onto the housing (figure 11). The lateral holders are adjusted to the right height of the vessel 11k and fixed in position by rotating ring 11l. Elastic O-rings 11m affix the side-necks to the holder.

Figure 7
Figure 11

2.1.3 Air outflow

Figure 12

Silicone seal, Teflon washer and screw-hole cap are placed onto the glas air outflow cooler (figure 12). A silicone tube is fixed onto the outflow cooler on one side and onto the corresponding filter on the other side. The air outflow cooler is now screwed into the side neck of the fermenter vessel (figure 13).

Alternativelly an electrothermical Peltier cooler can be used. It allows a much better condensation of water vapor because of low temperature attained (about 0 °C). No cooling water is required.

In practice the air filter is sometimes omitted and the out flowing air is lead into a 70 % ethanol solution.

Figure 13Figure 14

2.2 Cannulae for addition and sample collection

Figure 15

The large silicone plug is screwed, together with a washer, to the larger side neck using the screw-hole cap Pyrex 30. If necessary Luer-Lock end pieces are mounted onto the top of the cannulae (figure 14). The long cannula is preferably used for sample collection, the shorter cannulae are used for addition of pH-adjusting substances and inoculation.

2.3 Probes

The pH-, pO2- or other probes are connected correspondingly. After calibration they are provided with a silicone plug, Teflon washer and screwed onto the side necks with the aid of a screw-hole cap (figure 15).

Before sterilisation the vessel is filled with medium and all unused side necks are sealed with a silicon stopper, gasket and a cap. The probe connectors have also to be protected with a cap, unless they are of the VarioPin type, which does not need protection.


3.1 Connections

The cooled off fermenter vessel is placed into the ring above the infrared heat emitter and has to be well supported by the lateral holders (figure 11). The lateral holders are fixed in position by rotating ring 11l. Elastic O-rings 11m affix the side-necks to the holder.

Figure 16Figure 17Figure 18

3.2 Start-up of the fermenter

After a last control of the connections, press key "R". Regulation is now activated.
Once the desired parameter values are reached, inoculation can be performed.



MINIFOR laboratory fermenter does not need any special maintenance. Keep the fermenter clean. Clean it with a humid cloth. Common detergents or ethanol can be used as well.


If a liquid or saline solution gets into the back side of the fermenter (power supply), pull out the line cord immediately and contact our customer service.


Compact microprocessor controlled laboratory fermenter MINIFOR

Power:mains 90—240 V AC / 50—60 Hz, 400 W, CE conform (other voltages on request)
Dimensions:22 × 40 × 38 cm (W × D × H)
Display:LDC 4 × 40 digits with backlight
Fermentor / fermenter vessel:Pyrex glass with 5 to 8 side necks (culture volumes from 35 ml to 4.5 l)
Temperature control:special radiation heat source with gilded reflector 150 W,
Regulation:from 5 °C over RT to 70 °C
Measurement:from 0 to 99.9 °C in 0.1 °C steps
Precision:± 0.2 °C (0 to 60 °C)
Sensor:Pt 100 incorporated in the pH sensor
pH control:sterilisable pH electrode pH 0—13, with automatic temperature correction, Variopin connector, two-point semiautomatic calibration
Resolution:0.01 pH unit
Precision:± 0.02 pH unit
pO2 control:sterilisable Clark type oxygen sensor with fast response and reinforced Teflon membrane, measurement and regulation through regulation of airflow rate,
Range:0 to 25 mg oxygen/l, in 0.1 mg/l steps
Air flow:0 to 5 l/min. in 0.1 l/min. steps, mass flow meter, linearity ± 3 %, reproducibility ± 0.5 %
Control:proportional valve using memory metals
Supplied air pressure:between 0.05 and 0.2 MPa
Agitation:40 W Vibromixer 0 to 20 Hz with 1 or more stirring discs; sterility similar to magnetic coupling
Selectable parameter:an additional parameter ("X") can be controlled by the instrument (foaming control, pCO2, optical density, conductivity, weight etc.)
Sampling ports:up to four needles with Luer-Lock or multiseal PEEK fittings can be used for sampling and addition of correction solutions
Pumps:up to 4 independent pumps with speed variation from 0 to 100 % can be used with Minifor (Preciflow, Multiflow or HiFlow)
Working temperature:0—40 °C
Working relative humidity:0—90 %
Weight:7.5 kg
PC control:complete PC control and date treatment using FNet program for Fermentors from Sysmatec or SIAM fermentation software

Inputs and Outputs:

Pump connection (8-pin connector):
Image of 8-pin connector
Pin no.:cable colour code
1Input remote control + 0/10 V (yellow)
2Step frequency of pump motor (0 and 12V) (grey)
3Power supply 0 V (green)
4Power supply + 12 V (brown)
5Pump remote control ON/OFF (0 to +12 V) (white)
6RS485 GND
7RS485 B (—)
8RS485 A (+)
PC-connector: 9-pin
Electrodes: pH and temperature, cable with VarioPin connector
Oxygen: BNC connector
Additional probe: BNC connector (antifoam, pCO2, etc.) Input: 0—10V
Alarm-Output: Audio connector 12 V/0.1 A



12 months on material defects or manufacturing defectives, if the device was used according to the operation manual. Condition for reparation is delivery to our repair service with a detailed description of the failure. Transport costs and risks are for the customer's account.