Anaerob incubation by commercial gas-generating envelopes in sealed anaerobic jar. An indicator strip that turns white in anaerobic atmosphere is included in the jar. - Click on the image to enlarge it.
Some pathogenic bacteria are anaeribic and have to be cultivated in an oxygen-free atmosphere. The method of choice is dependent upon how anaerobic the bacterium to be cultivated is. There are strictly anaerobic bacteria, which cannot withstand oxygen at all, and there are aerololerant anaerobic bacteria, which will survive if the exposure to oxygen is not too long.
Strictly anaerobic bacteria
If you work with strict anaerobes, or if you have large amounts of samples to cultivate from, you may prefer a so-called anaerobic chamber where you work with rubber gloves sealed to the chamber. The anaerobic chamber maintains a constant temperature and the atmosphere may e.g. consist of nitrogen (N2) and carbon dioxide (CO2).
If you work with aerotolerant anaerobes maybe you prefer a so-called anaerobic jar where chemicals are used to absorb oxygen (O2) and generates CO2. There are commercial systems for this purpose. The anaerobic jar can be placed in thermostatic cabinet during the incubation.