Public yeast culture repositories such as the USDA-NRRL collection, ATCC and CBS commonly receive type strains and other industrially and academically important strains from hundreds of depositors. Hence there is a great deal of overlap in holdings among these collections. However, the Phaff collection stands apart from these important global repositories. Since it is the research collection of one of the most important yeast microbiologists of the 20th century, roughly 80% of the strains in the Phaff collection are not available from any other source. The unique contents of the collection are truly remarkable. For example:
- Heirloom wine yeast strains were isolated by Bioletti and Cruess from wineries in California and Europe before the 1940s, before commercial inocula were routinely used. The oldest strains in fact have been maintained since 1893.
- The collection contains a number of pigmented yeast species, including Phaffia rhodozyma, isolated by Miller and named for Phaff, which produces astaxanthin, a natural color also found in certain algae. While the industrially important type strain is available from other public collections, a number of additional strains are maintained only in the Phaff collection.
- Strains were isolated from habitats that have since been destroyed by human development or other factors, such as cacti in the Caribbean.
- Variants of established strains are maintained in the collection, which are important for studies of microbial biogeography, diversity, and ecology.
- Ribosomal sequence analysis has revealed upwards of 100 unpublished species, available from no other source.
World map featuring areas of research which have contributed to the collection
Red stars: source
of yeasts isolated by Phaff.
Yellow stars: source of
yeasts isolated by Boundy- Mills.