F-915 ORP FermProbe with T-Pull Cap

Reasons to Measure ORP in Fermentation Media

The metabolic activity of microorganisms depends on many factors, including the ORP potential of the culture environment. Measuring the ORP potential allows the vessel operator to monitor the addition of reducing agents while ensuring that the potential is in the proper range for initiation of growth. It is also important to monitor the ORP potential just before inoculation.

Anaerobic fermentation

ORP sensors are most commonly used to maintain anaerobic conditions in a culture media. They can be used to measure trace amounts (<1 ppm) of dissolved oxygen, at levels that are too low for D.O. sensors.

Downstream Processing

Sometimes used in steps performed downstream of the fermentation process, ORP sensors can monitor changes in concentration or the absence or presence of specific chemicals. Monitoring the ORP potential is an effective way of tracking chemical conversions in the process.

Protein folding

The close regulation of ORP potential is crucial to allow efficient formation of disulfide bonds, which facilitate folding and the stability of the folded protein. Overly oxidizing conditions can result in misfolding due to the formation of incorrect bonds.

Metabolic pathways

Measuring the ORP potential is an effective way to determine its influence on the metabolic pathways of microorganisms. This is useful for substrate utilization or the production of specific metabolites.

Specification

• ± 5000 mV range
• Steam sterilizable to 135°C
• 150 psig maximum pressure
• Double junction, Ag-AgCl reference system
• Metric Pg13.5 threaded disconnect cap

For a K9 cable connector use the F-995 Redox FermProbe instead.

How to Order a ORP Electrode

1. Choose Electrode Model – If the electrode needs to fit an existing cable, check the cable connector and note its color. If the cable connector is black and has an S8 connector, use the F-915 or F-935 ORP FermProbes. If the cable connector is red or orange and has a K9 connector, use the F-995 ORP FermProbe.
2. Choose Electrode Length – If you have already chosen a housing, select an electrode length with the same Class designation as the housing. The housing ordering information box also lists the correct electrode length to order. If you have not already chosen the housing, please review the recommendations next to each electrode model below.
3. Confirm Cable Length and Connector.

Model F-915, F-935, and F-995 ORP electrodes require disconnect cable and connector assemblies.

Series F-900 ORP FermProbes

Recommended Housings

The F-915 Redox FermProbe Electrode has a metric Pg13.5 threaded polymer cap allowing it to be used with European style housings. We recommend the following Broadley-James sensor housings for use with the FermProbe F-915 Redox FermProbe electrode:

• Model 320 Unguarded Sensor Housing – Standard 25mm, typical electrode insertion lengths 37mm, 66mm & 113mm
• Model 330 Guarded Sensor Housing – Standard 25mm, typical electrode insertion lengths 52mm, 81mm & 128mm
• The F-915 Redox FermProbe electrode can also be used with Models 326, 336, 350 and 357

Compatible Cables

The T-Pull style F-915 Redox FermProbe uses a standard S8 detachable cable connection. We recommend the following cables for use with it:

Cable Type	Sensor Connector & Device Connector	Device Terminal
HP Plug to BNC Plug, Type A
HP Plug to BNC Plug, Type M
HP Plug to DIN Plug, Type M
HP Plug to Crimped Ferrules, Type M
HP Plug to Ferrules, Solution Ground, Type N

Additional information

• The terms are interchangable in meaning: ORP = Oxidation-Reduction Potential (Redox)
• The term ORP is more commonly used for bioprocess applications in Europe and the U.S.
• The term Redox is more commonly used for industrial chemical process applications in the U.S.
• The ORP potential of a media is related to the overall availability of electrons in the media, specifically the ratio of positive and negative ions in the solution. Note that ORP measurements vary significantly with changing pH.