Why is agar preferable to gelatin as a solidifying agent in culture media?

Answer 1

Agar, which is an extract of red marine algae, is preferred because only a few microbes can degrade the agar. It will remain as a solid during the growth of bacteria. It will stay as a liquid until cooled to 40 degrees Celsius. Once a solid, it will stay solid unless incubated at temperatures over 85 degrees Celsius.

Agar melts at 85 °C (358 K, 185 °F) and will solidify from 32-40 °C (305-313 K, 90-104 °F). Since many scientific applications require incubation at temperatures close to human body temperature (37 °C), agar is more appropriate than other solidifying agents that melt at this temperature, such as Gelatin.

Answer 2

Agar is preferable to Gelatin in culture media because agar is derived from seaweed and is less likely to be degraded by microorganisms, making it a more stable solidifying agent. Additionally, agar can solidify at a higher temperature, allowing for a wider range of growth conditions for microorganisms compared to gelatin.

Answer 3

"No living organism has yet been recorded as being able to metabolize (or eat/digest) agar, which is not true about gelatin. Gelatin used to be the main solidifying agent until agar was found to be better (agar is a solidifying agent which is used in Asian cuisine because it is easily extracted from algae). "

This is incorrect. There are many agar digesting bacteria and fungi that have been found. Agar is preferable to gelatin for several reasons, it is a more consistent product with fewer impurities, less ethical concerns (animal hoofs versus algae) and is more effective as a solidifying agent than gelatin (0.7% agar is equivalent to 1.8% gelatin media)

the basic reason for the agar to be preferred over gelatin is much more technical than the above two reasons, agar is having a far more melting point than the gelatin.... it can melt over 60 degree Celsius but the gelatin on other hand takes much less temperature to melt and thus even gets liquefied at much lower temperatures like 37 to 40 degree Celsius.

the another reason also lies in the extraction procedures of the two mediums... gelatin is extracted from the bones of animals which makes it far more less accessible than the agar which can be extracted easily from the overgrowing algae called geledium....

Answer 4

Agar, which is an extract of red marine algae, is preferred because only a few microbes can degrade the agar. It will remain as a solid during the growth of bacteria. It will stay as a liquid until cooled to 40 degrees Celsius. Once a solid, it will stay solid unless incubated at temperatures over 85 degrees Celsius.

Agar melts at 85 °C (358 K, 185 °F) and will solidify from 32-40 °C (305-313 K, 90-104 °F). Since many scientific applications require incubation at temperatures close to human body temperature (37 °C), agar is more appropriate than other solidifying agents that melt at this temperature, such as gelatin.

Answer 5

Dr. Saxena says that agar is not hydrolyzed by most molecules, and agar doesn't liquidify till about >95'C. Once it has been solidified, and then it solidifies only at <50'C.

In contrast, Geletin liquidify at >28'C

and can be broken down by many organisms- pathogens.

Answer 6

Because of it's ability to absorb and retain large amounts of water.

Answer 7

Agar is used as a solidifying agent in culture media instead of gelatin because agar remains as a solid during growth of bacteria. Few microbes can degrade agar.

Answer 8

Because Agar is the solidification agent. Otherwise, the media would stay liquid !

Answer 9

agar remains as a solid during growth of bacteria and few microbes can degrade agar