METHANOL SENSOR SYSTEM

The Raven Biotech stand-alone Methanol Sensor Model 2.1 systems provides reliable, on-line control of methanol concentration in cultures of Pichia pastoris, allowing fast and efficient optimization of recombinant protein production. Accurate regulation of the methanol concentration is necessary to maintain induction and prevent the accumulation of methanol to cytotoxic levels.

In the past, the dissolved oxygen spike method has been used to estimate the methanol concentration. This technique, however, exposes the cells to potentially non-inducing levels of methanol and cannot be easily implement with Mut^- clones or with mixed substrate feeds.

Raven's Methanol Sensor overcomes these limitations, giving accurate monitoring and control of methanol concentration in cultures of Mut⁺, Mut^- and Mut^S recombinant Pichia pastoris clones.

The system has been designed to easily connect to an existing system without using a large amount of valuable benchspace. This is a complete stand alone unit providing monitoring and control of methanol concentration, and a computer is not required. Data logging can be performed by a simple connection of a 0-10 volt chart recorder to the rear panel or logged into a simple terminal program on a PC.

Although the Methanol Monitoring and Control Sensor has been designed for the control of methanol concentration in Pichia pastoris fermentation and since measurement of vapor occurs in the liquid combustible phase, this system may prove itself useful in many other applications.

Repressive carbon sources such as glucose or ethanol both exhibit different effects, and complete utilization of such carbon sources in the batch phase allows depression. Since the Raven Methanol Monitoring and Control System also detects ethanol, if during the batch phase an increase in sensor signal is observed, this may indicate ethanol production. By allowing complete exhaustion of the ethanol prior to methanol induction, repression can be avoided.

Mixed feeding protocols, mainly implemented with Mut^S strains can be a very effective means of increasing productivity of your protein of interest. In the past, various compositions of mixed carbon feeds e.g. glycerol/methanol have been employed to increase productivity. With the ability to monitor and control the methanol concentration, one can separate feeding systems for glycerol addition, thus allowing the user more flexibility in maintaining limited glycerol concentrations.