Angelina Fanny Hesse (Figure 1), called Lina by her family, was the one who knew about something better for making solid growth media. Hesse and her husband Walther were part of Robert Koch’s lab in Germany. While a student, Walther was struggling with growing microorganisms from air due to the inherent issues of working with gelatin in microbiology.
According to their grandson, Wolfgang Hesse, Walther noticed her jellies and puddings were not melting and asked what she used. So, Hesse told him about this ingredient called agar she added to maintain the consistency of her foods even in warm weather. She had used agar while cooking at home ever since a neighbor from Indonesia introduced her to it when she was a child in New York.
Walther then took this helpful information about agar that he learned from Hesse and shared it with Koch. The lab now had a substance similar to gelatin that lacked the issues of melting at 37ºC or being degraded by bacteria. Koch documented the use of agar in their growth media in his publications. However, Koch credited neither Lina nor Walther for this contribution, which is why Hesse remains relatively unknown even today.
Angelina Fanny Hesse’s introduction of agar to microbiology is arguably one of the most important tools for moving the field forward.