Product of the month: July

Agar for microbiology30,30 / 500 g
Article No.1182GR500
List Price61,70 €

What would microbiology be without agar?
Microbiological culture media only become what they are through agar.
Namely solid! The natural product is obtained from red algae.
Chemically, agar is a mixture of the polysaccharides agarose and agaropectin. Agar offers everything you could wish for in a gelling agent: it makes the culture medium firm and supple, it is temperature-resistant (i.e. it does not melt at higher incubation temperatures of > 40°C) and it is not metabolised by bacteria and fungi.

From fruit jelly to the Petri dish

Agar was discovered as a perfect gelling agent for microbiology by Fanny Hesse in 1881. She was the wife of the microbiologist Walther Hesse, who was working on the isolation of various bacteria as an employee of Robert Koch. As chance would have it, Fanny came into contact with the gelling agent, which was still unusual in Europe at the time, through acquaintances and was already using it in the kitchen as a heat-resistant alternative to gelatine. Well informed about the positive properties of agar, she helped her husband on his way – and ultimately made a significant contribution to Robert Koch’s success in isolating the tuberculosis pathogen in 1882.

Another positive aspect in today’s world: agar is vegan, whereas gelatine is hydrolysed collagen from the connective tissue of animals (usually obtained from cattle and pigs).

Agarose, as used for gel electrophoresis, is the purified form of agar. It consists only of the linear, gellable agarose polysaccharide.