Rhodotorula cycloclastica sp. nov., Rhodotorula retinophila sp. nov., and Rhodotorula terpenoidalis sp. nov., three limonene-utilizing yeasts isolated from soil.

During a search for yeasts that hydroxylate monoterpenes, four yeast strains were isolated from soil and plant residue in monoterpene-rich environments using enrichment techniques with cyclohexanedioic acid or cyclohexanedimethanol as sole carbon source. These strains were able to utilize (+)-limonene supplied as a vapor as only carbon source. The yeasts have a CoQ-10 system. Morphology and physiological properties of the strains did not fit any known yeast species. Recent analysis of the 26S D1/D2 and ITS-5.8S rDNA sequences of basidiomycetous yeasts showed that these strains represented three hitherto unknown species of Rhodotorula and fell in a cluster consisting of Rhodotorula philyla and the mycoparasitic fungus Colacogloea peniophorae. Descriptions of three new species Rhodotorula cycloclastica (type strain TVN 309=UOFS Y 2046=CBS 8448), Rhodotorula retinophila (type strain TVN 295=UOFS Y 2043=CBS 8446), Rhodotorula terpenoidalis (type strain TVN 310=UOFS Y 2042=CBS 8445) are proposed to accommodate these isolates.