One challenge is that much early research was not done in English.
The earliest scientific reference to the kombucha culture was in 1913 by Gisevii Lindau. [Lindau, G., Ueber Medusomyces Gisevii, eine neue Gattung und Art der Hefepilze. Berichte deutsch. Bot. Ges. 31, 243-248 (1913).] Here is a reference made to it in English from a 1920 encyclopedia on yeasts. At first, he thought it was a single fungus, but his colleague Dr. Lindner realized that it was a mixture of many cultures, and published a correction. [Lindner, P., Die vermeintliche neue Hefe Medusomyces Gisevii. Ber. deutsch. Bot. Gesell. 31, 364-368 (1913).]
Courland, where Dr, Lindau first noticed kombucha tea, was a part of Russia in 1913. Now it is in Latvia. How kombucha came to be known by that name (which is properly the name of an unrelated Japanese kelp drink) I do not know, although it was referred to by that name in the scientific literature as early as the late 1920s. [Hermann, S., Uber die sogenannte ‘Kombucha’. Biochem. Z. 192, 176-199 (1928).]
