Isolation And Identification Of Alkalitolerant Yeasts And Studies On β-carotene Produced By Rhodotorula Mucilaginosa XJU-1

Alkali-tolerance and alkaliphily have been for a long time considered a peculiarity of a limited group of prokaryotes. In recent years, a large number of alkalitolerant or basophilic bacteria and archaea have already been isolated from various environments, but little alkalitolerant yeasts have been investigated.An Alkalitolerant red yeast strain XJU-1 was originally isolated by dilution-plate technique from a waste of lawn in Urumqi city of Xinjiang, China. It can grow in nutrient broth at a broad range of pH values from 3.5 to 11.0. Morphological, physiological and biochemical characterization indicated that this strain belonged to the genus Rhodotorula. Molecular taxonomic analysis based on the 26S rDNA D1/D2 domain sequence showed that the strain XJU-1 is closely related to Rhodotorula mucilaginosa CBS17 with 100% identity, for which the name Rhodotorula mucilaginosa XJU-1 is proposed. The sequence analysis of the 5.8S-ITS domain is employed to confirm identifications. The GenBank accession number for the 26S rDNA D1/D2 domain sequence and 5.8S-ITS domain sequence were DQ132885 and DQ132886, respectively. This strain deposit number is CGMCC.No1536.An alkalitolerant yeast strain XJU-2 was originally isolated from an industrial sewage farm in Wenquan county of Xinjiang, China, and was grown in Potato-dextrose agar medium. The isolate can grow in nutrient broth at a broad range of pH values from 3.5 to 11.0. The halotolerance of the strain XJU-2 was high up to 12%, and the temperature tolerance was up to 45℃. Morphological, physiological and biochemical characterization indicated that this strain belonged to the genus Saccharomyces. Molecular taxonomic analysis based on the 26S rDNA D1/D2 domain sequence showed that strain XJU-2 is closely related to S. cerevisiae...