Yeast Consortium Research Articles

Isolation of a lactic acid bacterium and yeast consortium from a fermented material of Ulva spp. (Chlorophyta)

Microbiota in a fermented culture of Ulva spp. was examined with the objective to characterize the type of fermentation and to obtain starter microbes for performing seaweed fermentation. Fermented Ulva spp. cultures which were obtained and transferred in a laboratory were examined for their microbiota. With phenotypic characterization and phylogenetic analysis based on rRNA gene nucleotide sequences, the predominant micro-organisms were identified as Lactobacillus brevis, Debaryomyces hanseni var. hansenii, and a Candida zeylanoides-related specimen, suggesting that the observed fermentation can be categorized to lactic acid and ethanol fermentation. Inoculating the individually cultured cell suspensions of the three kinds of micro-organisms with cellulase induced the fermentation in various kinds of seaweed. A microbial consortium composed of a lactic acid bacterium, L. brevis, and yeasts, D. hansenii and a C. zeylanoides-related specimen, were predominant in a fermented culture of Ulva spp. Lactic acid and ethanol fermentation could be induced in various kinds of seaweed by adding this microbial consortium along with cellulase. This is the first report of lactic acid and ethanol fermentation in seaweed, which is expected to provide a new material for food and dietary applications.

The Kombucha consortia of yeasts and bacteria

Kombucha teas produced by fermenting the ‘Manchurian mushroom’ are health beverages. The Manchurian mushroom, however, is not a mushroom but rather a poorly defined consortium of yeasts and bacteria. After keeping a Kombucha culture as a ‘laboratory mascot’ for several years, we have studied it by breaking it up into its component parts and comparing it with two other similarly macerated cultures. Not surprisingly, different Kombucha cultures differ from each other. The number of colony-forming units isolated from macerated Kombucha cultures increased when tea was omitted from the fermentation and decreased when no starter culture was used. Presumed to be beneficial to human health, Kombucha cultures may also make good model systems for the study of biofilms, microbial mats and other complex associations of microorganisms.