Agar-Agar (Bacteriological Agar)
 
Catalog Number: AS-1001
CAS Number: 9002-18-0
 
Agar-agar is a refined polymer driven from red algae. It is necessary for solidifying culture media in microbiology labs. Compared to gelatin, agar-agar is free of impurities and offers several advantages.
Agar-agar dissolves easily in boiling water but is insoluble in cold water. Significantly, it solidifies between 32 to 40°C, which is the ideal temperature range for bacterial growth and keeps its firmness at temperatures that are commonly used for bacterial cultivation.
Agar-agar culture medium is extremely resistant to being broken down by enzymes released by a variety of microbes. This allows appropriate bacterial growth and ensures the integrity of the culture media.
 
Agar-Agar Concentration in Culture Media
The concentration of agar-agar in culture media varies depending on its application:
Optimal Solidification: For solid bacterial culture media, a concentration of 1-1.5% agar-agar is typically used to ensure robust solidification.
Motility Assays: Lower concentrations, approximately 0.5%, are employed to facilitate bacterial movement within the gel matrix.
Anaerobic Bacteria: Certain anaerobic bacteria, which may be sensitive to more restrictive environments, can be cultured using very low agar concentrations, such as 0.1%.
pH Considerations: The gelling properties of agar-agar can be influenced by the acidity (pH) of the culture medium. For media with a pH lower than 5, it may be necessary to use a slightly higher concentration of agar (at least 2%) to achieve adequate solidification.
 
Shelf life and storage
Store below 30 °C in a tightly closed container. Keep away for, heat and humidity. Under these conditions agar-agar has a shelf life of 5 years from the date of production.
 
For Laboratory Use Only.