Submitted to: Canadian Journal of Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/24/1999
Publication Date: N/A
Interpretive Summary: Yeasts have many important biotechnological uses ranging from bread making to the production of pharmaceuticals by genetically enhanced strains. Continued advances in biotechnology are dependent on genetic modification of known yeasts and the discovery of new species with novel properties. In a program to find new species of biotechnological importance, the thousands of unidentified yeasts maintained in the ARS Microbial Culture Collection are being characterized from their distinctive gene sequences. This report describes three new yeasts that were detected by this strategy: Pichia panamericana, Candida piceae, and Candida wyomingensis. Of the three, Pichia panamericana looks most promising for biotechnological exploitation because it is heterothallic (has mating strains for breeding) and it grows on methanol. The methanol biochemical pathway can be easily modified to produce large amounts of unique chemicals and since the new yeast is heterothallic, novel genetic modifications can be easily done.
Technical Abstract: A new species of Pichia and two new species of Candida are described and were determined to be genetically isolated from all other currently recognized ascomycetous yeasts from their sequence divergence in the species-variable D1/D2 domain of large subunit (26S) ribosomal DNA. The three species were primarily isolated from the frass of wood-boring insects living in pine and spruce trees. The new species and their type strains are the following: Pichia panamericana NRRL YB-1985 (CBS 8699), mating type alpha (NRRL YB-3835, CBS 8700, mating type a), Candida piceae NRRL YB-2107 (CBS 8701), and Candida wyomingensis NRRL YB-2152 (CBS 8703). P. panamericana and C. piceae assimilate methanol as a carbon source; P. panamericana is the first known heterothallic ascomycetous yeast to utilize this compound.