Gas-pak
Encyclopedia
Gas-pak is a method used in production of an anaerobic environment. It is used to culture bacteria which die or fail to grow in presence of oxygen (anaerobes). It is a much simpler technique than the McIntosh and Filde's anaerobic jar
where one needs to pump gases in and out.
There are commercially available, use-and-throw sachets containing a dry powder or pellets, which when mixed with water and kept in an appropriately sized airtight jar, produces and atmosphere
free of elemental oxygen gas. These are used to produce an anaerobic
culture in microbiology
.
The addition of a Dicot Catalyst maybe required to initiate the reaction.
and carbon dioxide
along with sodium citrate and water (C3H5O(COONa)3) as byproducts http://en.wiktionary.org/wiki/byproduct. Again, Hydrogen, in presence of oxygen and a catalyst like Palladium
ised alumina(supplied separately), combines to form water.
. The indicator tells whether the environment was indeed oxygen free or not.
Indicator: Generally used chemical indicator for this purpose is "chemical methylene blue solution" that has never since synthesis been exposed to elemental oxygen. It is colored deep blue on oxidation in presence of atmospheric oxygen in the jar, but will become colorless when oxygen is gone, and anaerobic conditions are achieved.
McIntosh and Filde's anaerobic jar
McIntosh and Filde's anaerobic jar is an instrument used in the production of an anaerobic environment. This method of anaerorbiosis as others is used to culture bacteria which die or fail to grow in presence of oxygen .-Construction:...
where one needs to pump gases in and out.
There are commercially available, use-and-throw sachets containing a dry powder or pellets, which when mixed with water and kept in an appropriately sized airtight jar, produces and atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
free of elemental oxygen gas. These are used to produce an anaerobic
Anaerobic organism
An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It could possibly react negatively and may even die if oxygen is present...
culture in microbiology
Microbiology
Microbiology is the study of microorganisms, which are defined as any microscopic organism that comprises either a single cell , cell clusters or no cell at all . This includes eukaryotes, such as fungi and protists, and prokaryotes...
.
Constituents of gas-pak sachets
- Sodium borohydrideSodium borohydrideSodium borohydride, also known as sodium tetrahydridoborate, is an inorganic compound with the formula NaBH4. This white solid, usually encountered as a powder, is a versatile reducing agent that finds wide application in chemistry, both in the laboratory and on a technical scale. Large amounts are...
- NaBH4 - Sodium bicarbonateSodium bicarbonateSodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula Na HCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda . The natural mineral form is...
- NaHCO3 - Citric acidCitric acidCitric acid is a weak organic acid. It is a natural preservative/conservative and is also used to add an acidic, or sour, taste to foods and soft drinks...
- C3H5O(COOH)3 - Cobalt chloride - CoCl2 (catalyst)
The addition of a Dicot Catalyst maybe required to initiate the reaction.
Reactions
- NaBH4 + 2 H2O = NaBO2 + 4 H2↑
- C3H5O(COOH)3 + 2 NaHCO3 +
[ CoCl2] = C3H5O(COONa)3 + 3 CO2 + 3 H2 +[ CoCl2] - 2 H2 + O2 +
[ Catalyst] = 2 H2O +[ Catalyst]
Consumption of oxygen
These chemicals react with water to produce hydrogenHydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
and carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
along with sodium citrate and water (C3H5O(COONa)3) as byproducts http://en.wiktionary.org/wiki/byproduct. Again, Hydrogen, in presence of oxygen and a catalyst like Palladium
Palladium
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...
ised alumina(supplied separately), combines to form water.
Culture method
In an air-tight gas jar the culture media, the gas-pak sachet (opened and water added) and an indicator are placed. The jar is incubated at the desired temperatureTemperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
. The indicator tells whether the environment was indeed oxygen free or not.
Indicator: Generally used chemical indicator for this purpose is "chemical methylene blue solution" that has never since synthesis been exposed to elemental oxygen. It is colored deep blue on oxidation in presence of atmospheric oxygen in the jar, but will become colorless when oxygen is gone, and anaerobic conditions are achieved.