What Is Cultural Medium
Posted: Sun Dec 07, 2014 1:22 pm
I know what petri dishes are and agar are(LOL That Rhymed) but what is cultural medium?
Hi,
When bacteria are grown on agar plates or in liquid the process is called culturing. The purpose of the agar is just to provide a solid surface on which bacterial colonies can grow, but they cannot grow on agar alone. The bacterial cells, just like cells in your body, need nutrients--proteins, carbohydrates, minerals, etc. The 'culture medium' is what is added to the agar to feed the bacteria.
If you have nutrient agar plates it means that the agar and water also contains beef extract and peptone. E coli and many other kinds of bacteria will happily grow on nutrient agar. Bacteria can also be cultured in liquid without agar. The same ingredients are used and the culture medium is then called nutrient broth. http://www.thelabrat.com/protocols/NutrientAgar.shtml
In some cases we want to grow bacteria under more controlled dietary conditions and for that we use what is called a minimal salts medium. This is called a defined medium because we know all the ingredients and add them separately: http://www.thelabrat.com/protocols/m9minimal.shtml
If you have more questions about bacteria and working with them, please ask. There are a lot of little details you need to pay attention to in order to get good results when using E coli for experiments and we can help you understand the procedures.
Good luck!
Sybee