When processing the jars with the Anoxomat using the anaerobic recipe, a mere 0.16% of Oxygen still remains in the jar. A small catalyst is needed to obtain and maintain absolute anaerobiosis. Media, if they are not pre-reduced contain oxygen, which will be released in the jar atmosphere during incubation. Also the inoculate may produce oxygen during the incubation.

Working principle of the catalyst:
The addition of 10% hydrogen in the gas mixture and the Catalyst will ensure the catalytic removal of oxygen.
The function of the catalyst is to stimulate the reaction of H₂ with O₂ to H₂O. At the end of the anaerobic program on the Anoxomat, there is a little overpressure in the jar. After a few minutes the catalyst takes care that the pressure in the jar reduces and that there's no oxygen left.

The catalyst can be used numerous times by reactivating it in a hot-air oven (for 30 minutes at 160°C or for 60 minutes at 100°C to dry it thoroughly). For this reason, 2 (sets) of catalyst should be available. One (set) is in the jar during incubation, a second (set) is being regenerated in the hot-air oven.

According to the UK Department of Health recommendations, a minimum of 1-gram palladium coated pellets per liter volume is needed in an anaerobic jar.

The Mart Catalyst consists of a steel gauge sachet with palladium-coated aluminium pellets and can be clipped under the lid of the jar. It is a cold catalyst.

Mart Microbiology supplies Catalysts in 2 sizes. One for small jars and one for bigger jars.