Anaerobes are microorganisms that grow in the absence of oxygen.
Cultivating anaerobes requires special techniques to create and maintain oxygen-free environments.
Two common methods for cultivating anaerobes are the candle jar method and the GasPak jar method.
1) Candle Jar Method
Description: A simple and inexpensive method to create a microaerophilic (low oxygen) environment.
Procedure:
Place culture plates inside a large, airtight jar.
Add a lit candle to the jar and seal the lid.
The candle burns, consuming most of the oxygen and increasing the levels of carbon dioxide until the flame extinguishes due to oxygen depletion.
Applications: Suitable for growing microaerophilic bacteria and some facultative anaerobes that require reduced oxygen levels but not complete anaerobiosis.
Advantages: Easy to set up and inexpensive.
Disadvantages: Does not achieve complete anaerobic conditions; only reduces oxygen levels.
2) GasPak Jar Method (Cultivation of Anaerobes)
Description: A widely used method for creating an anaerobic environment using chemical reactions.
Procedure:
Place culture plates or tubes inside the GasPak jar.
Add a GasPak sachet to the jar, which contains chemicals that, when activated, generate hydrogen and carbon dioxide gases.
Seal the jar tightly. The hydrogen gas reacts with oxygen in the presence of a palladium catalyst to form water, thus removing oxygen and creating an anaerobic atmosphere.
An indicator strip is often used to confirm the absence of oxygen.
Applications: Suitable for the cultivation of obligate anaerobes, facultative anaerobes, and microaerophiles.
Advantages: Reliable and produces a true anaerobic environment.
Disadvantages: Requires the purchase of GasPak sachets and a specialized jar.