Typical voltage output of sensor on-line calibration prior to the induction phase of fermentation.
Methanol sensor output in millivolts during Pichia pastoris fermentation.
(A) Batch phase – the baseline voltage corresponds to a methanol free signal followed by an on-line calibration.
(B) Discrete 0.1% doses of methanol were added up to 0.5% for calibration and to initiate induction. The methanol was then allowed to be consumed, dropping to the user defined set point
of to 0.3% methanol (from the calibration equal to 2.6 volts).
(C) With the methanol pump set to deliver 0.6 mls/min, automatic on/off control is established by the Sensor.
(D) The base line voltage was rapidly verified by disconnecting the probe tubing and connecting the inlet/outlet fittings on the Sensor unit directly thereby bypassing the probe.
(E) The system is returned to stand alone control at 0.3% methanol.
(F) The set point was changed to 0.1% methanol (to observe the response time).
(G) The setpoint was readjusted to 0.3% and maintained throughout the remainder of the culture.
Schematic of Pichia pastoris
Fermentation System with