Gaspak Anaerobic jar

Gaspak Anaerobic jar for cultivation of anaerobic bacteria

This method is based on hydrogen generation in the jar. It can react with available oxygen to form water. Palladium pellets catalyst the reaction at room temperature. To ensure whether anaerobic atmosphere exists in the jar, an indicator strip of methylene blue is used that becomes colourless in the absence of oxygen.

If the strip is not decolourised within two hours, the gas contains oxygen and chemical reactions fail to occur. The jar is not sealed properly.

The entire assembly is placed at 37 C in an incubator for 24 to 48 hours and growth is recorded.


  • Gaspak anaerobic jar
  • Palladium pellets
  • Methylene blue
  • Bacterial culture
  • Nutrients agar plates


  1. Keep the streaked plates in the jar containing a gaspak indicator strip of methylene blue and gaspak generator envelopes.
  2. Pull the strip half way so that the change in color is visible.
  3. Cut the envelopes and add 10 ml tap water into the open envelope.
  4. Close the whole assembly as per protocol and keep at 37 C.
  5. Check the jar after 2 to 3 hours to see if the strip has lost its blue color.
  6. After 24 – 48 hours of incubation remove the lid.


Examine the plates after staining. Anaerobic microbes will show spore germination and vegetative hyphal propagation.


D. K. Dubey – Practical Microbiology

Gaurav Singh

Editor in Chief Medical Microbiology & RDT Labs - RDT Labs Magazine | BSc Medical Microbiology | MSc Microbiology

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