THE YEAST SPECTRUM OF THE TEA FUNGUS KOMBUCHA

The tea fungus 'Kombucha' is a symbiosis of Acetobacter, including Ace tobacter xylinum as a characteristic species, and various yeasts. A ch aracteristic yeast species or genus has not yet been identified. Kombu cha is mainly cultivated in sugared black tea to produce a slightly ac idulous effervescent beverage that is said to have several curative ef fects. In addition to sugar, the beverage contains small. amounts of a lcohol and various acids, including acetic acid, gluconic acid and lac tic acid, as well as some antibiotic substances. To characterize the y east spectrum with special consideration given to facultatively pathog enic yeasts, two commercially available specimens of tea fungus and 32 from private households in Germany were analysed by micromorphologica l and biochemical methods. Yeasts of the genera Brettanomyces, Zygosac charomyces and Saccharomyces were identified in 56%, 29% and 26% respe ctively. The species Saccharomycodes ludwigii and Candida kefyr were o nly demonstrated in isolated cases. Furthermore, the tests revealed pe llicle-forming yeasts such as Candida krusei or Issatchenkia orientali s/occidentalis as well as species of the apiculatus yeasts (Kloeckera, Hanseniaspora). Thus, the genus Brettanomyces may be a typical group of yeasts that are especially adapted to the environment of the tea fu ngus. However, to investigate further the beneficial effects of tea fu ngus, a spectrum of the other typical genera must be defined. Only thr ee specimens showed definite contaminations. In one case, no yeasts co uld be isolated because of massive contamination with Penicillium spp. In the remaining two samples (from one household), Candida albicans w as demonstrated. The low rate of contamination might be explained by p rotective mechanisms, such as formation of organic acids and antibioti c substances. Thus, subjects with a healthy metabolism do not need to be advised against cultivating Kombucha. However, those suffering from immunosuppression should preferably consume controlled commercial Kom bucha beverages.