Who is credited with the use of agar in laboratory settings?

The use of agar in laboratory settings is credited to Fanny Hesse. She was instrumental in introducing agar as a solidifying agent in microbiological media during the late 19th century. Fanny Hesse's innovation came about when she suggested using agar, derived from red algae, as a substitute for gelatin. This was significant because gelatin posed several issues, such as being digested by some bacteria and providing inconsistent gel strength. Agar, on the other hand, is not digested by most microorganisms, can provide a stable medium for growth, and remains solid at a wider range of temperatures, making it highly suitable for pure culture techniques in microbiology.

Her contribution directly facilitated advances in microbiology, particularly in the work of her husband, Walter Hesse, and bacteriologist Robert Koch, who used agar in developing techniques to isolate pure cultures of bacteria. This innovation greatly enhanced the ability to study microorganisms in various conditions, leading to numerous discoveries in the field.