Agar-Agar, granulated

Agar-Agar, Granulated

Cat. No. 1.01614.1000/5007
(1 kg, 5 kg)

Solidifying agent used in the preparation of microbiological culture media.

Agar-agar is a polygalactoside, which is obtained from certain marine red algae. Some of its hydroxyl groups are esterified with sulfuric acid. Most microorganisms are incapable of degrading agar-ager.

Addition of about 10-15 g agar-agar/liter is sufficient for the preparation of solid culture media that can be inoculated by streaking with a loop. If the culture medium has a pH value of below 5.0, the concentration should be increased to 20 g/liter or, better still, the pH should be adjusted after sterilization. Semi-solid culture media contain 3-8 g agar-agar/liter while slightly viscous broths contain about 0.5-1 g/liter.

Agar-agar for microbiology is specially purified and free from antimicrobial inhibitors. 12 g agar-agar dissolved in 1 liter freshly distilled or demineralized water gives a clear gel when poured into the culture vessel (Petri dish, test tube).

Quality Control	Data
Analysis

Quality control

Test strains	Growth
Escherichia coli ATCC 25922	+
Streptococcus pyogenes ATC 21059	+
Streptococcus agalactiae ATCC 13813	+
Streptococcus equinus DSM 20062	+
Streptococcus pneumoniae ATCC 6301	+
Staphylococcus aureus ATCC 25923	+
Shigella sonnel ATCC 29930	+
Erysipelothrix rhusiopathiae ATCC 19414	+

Analysis
Loss on drying (105°C, 4 h): < 12 %; sulfated ash (600°C): < 6 %; heavy metals (Pb): < 0.001 %; calcium: < 0.5 %; magnesium: < 0.1 %.

Data
12 g Agar-ager/liter in Standard I Nutrient Broth (EMD Cat. No. 1.07882.).
Solidification point: 32-36°C.
Gel strength ³ 50 g (acc. to I.D. COSTIN: Zbl. Bakt., I. Orig., 234; 536-553 (1976)).