• Production, characterization and biological activities of exopolysaccharides from a new cold adapted yeast: Rhodotorula mucilaginosa sp. GUMS16 (IBRC-M 30406)
  • Masoud Hamidi ,1,* Amir Reza Gholipour,2 Cédric Delattre,3 Rasool Mirzaei Seveiri,4 Faezeh Sesdighi,5 Setareh Kheirandish,6
    1. Guilan University of Medical sciences
    2. Guilan University of Medical sciences
    3. Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut Pascal, F-63000 Clermont-Ferrand, France
    4. Guilan University of Medical sciences
    5. Guilan University of Medical sciences
    6. Guilan University of Medical Sciences


  • Introduction: Due to the potential industrial and therapeutic applications of the yeast exopolysaccharides (EPSs), there has been an increasing demand to assess these biopolymers with improved characteristics. The present study was aimed to identify a new cold adapted yeast called Rhodotorula mucilaginosa sp. GUMS16 isolated from fallen leaf debris of Deylaman jungle, Guilan, North of Iran at biochemical and molecular level. Also, extraction and structural characterization of produced EPS as well as its possible antioxidant and antiproliferative activities was evaluated.
  • Methods: GUMS16 strain was cultured for 5 days and following isolation of supernatant, EPSs precipitated with adding of cold absolute ethanol and freeze-dried. The EPSs chemical structure was determined by FT-IR, SEM, HPLC-SEC and GC-MS. Additionally, the solubility of EPSs were evaluated. In vitro, antioxidant activity was investigated against DPPH, hydroxyl and superoxide free radicals. Finally, the EPSs effect on the cell proliferation of human breast adenocarcinoma (MCF-7), Human poorly differentiated gastric cancer (MKN-45) and Human Dermal Fibroblasts (HDF) lines was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.
  • Results: The colony of GUMS16 cells on YPG medium was orange, shiny, mucoid, and smooth. The 5.8-ITS rRNA gene sequence of GUMS16 was submitted to the GenBank under accession number MF289167.1. Strain GUMS16 proved to be a cold adapted yeast and able to grow at 4 °C unlike the references strains of R. mucilaginosa. GUMS16 excreted 28.5 g/l of the EPSs. The molecular weight was approximately 84 kDa. Mannose and glucose were found as the main monosaccharides of the EPSs (85:15 mol%, respectively) through GC-MS analysis. In vitro, the EPSs showed a good free radicals scavenging activity. No significant difference among the EPSs treatments on the proliferation of MCF-7, MKN-45 and HDF cell lines was observed (P>0.05). According to the no cytotoxicity effect of the EPSs on the model of normal cells (HDF cell line), they could be well biocompatible.
  • Conclusion: These results indicate the desirable potential of the EPSs from GUMS16 as biocompatible compounds for using in food and pharmaceutical fields.
  • Keywords: Exopolysaccharides, R. mucilaginosa, antioxidant activity, biocompatible