Indigenous Yeasts from Rose Oil Distillation Wastewater and Their Capacity for Biotransformation of Phenolics.

The indigenous yeasts associated with the spontaneous fermentation of phenolic-rich rose oil distillation wastewater (RODW) generated after the industrial distillation of rose oil were studied. The ITS-rDNA sequence analysis of the samples collected from RODW fermented at semi-sterile conditions, a waste deposition lagoon and endophytic yeasts isolated from industrially cultivated Rosa damascena suggests that the spontaneous RODW fermentation is caused by yeasts from the genus Cyberlindnera found also as endophytes in the rose flowers. Phylogenetic analysis based on the nucleotide sequences of the translation elongation factor (TEF1α) and 18S- and 26S- rRNA genes further confirmed the taxonomic affiliation of the RODW yeast isolates with the genus Cyberlindnera . The RODW fermentation capacity of a selected set of indigenous yeast isolates was studied and compared with those of common yeast strains. The indigenous yeast isolates demonstrated a superior growth rate, resulting in a nearly double reduction in the phenolic content in the fermented RODW. The indigenous yeasts' fermentation changed the RODW phenolics' composition. The levels of some particular phenolic glycosides decreased through the depletion and fermentation of their sugar moiety. Hence, the relative abundance of the corresponding aglycons and other phenolic compounds increased. The capacity for the biotransformation of RODW phenolics by indigenous yeasts is discussed.