Evaluation of two fungal exopolysaccharides as potential biomaterials for wound healing applications

Microbial exopolysaccharides (EPSs) are mostly produced by bacteria and fungi and have potential use in the production of biomedical products such as nutraceuticals and in tissue engineering applications. The present study investigated the in vitro biological activities and in vivo wound healing effects of EPSs produced from a Sclerotium-forming fungus (Sclerotium glucanicum DSM 2159) and a yeast (Rhodosporidium babjevae), denoted as scleroglucan (Scl) and EPS-R, respectively. EPS yields of 0.9 ± 0.07 g/L and 1.11 ± 0.4 g/L were obtained from S. glucanicum and R. babjevae, respectively. The physicochemical properties of the EPSs were characterized using infrared spectroscopy and scanning electron microscopy. Further investigations of the biological properties showed that both EPSs were cytocompatible toward the human fibroblast cell line and demonstrated  hemocompatibility. Favorable wound healing capacities of the EPSs (10 mg/mL) were also established via in vivo tests. The present study therefore showed that the EPSs produced by S. glucanicum and R. babjevae have the potential use as biocompatible components for the promotion of dermal wound healing.

Accumulation of neutral lipids and carotenoids of Rhodotorula diobovata and Rhodosporidium babjevae cultivated under nitrogen-limited conditions with glycerol as a sole carbon source

A total of two red oleaginous yeasts, Rhodotorula diobovata and Rhodosporidium babjevae, were investigated for their potential to grow on nitrogen-limited media with sufficient glycerol as carbon source and produce biomass, triacylglycerides (TAGs) and carotenoids. The two yeasts produced equal quantities of biomass by 120 h post-inoculation (h pi), but R. diobovata consumed more glycerol than R. babajavae under the same conditions. The TAG concentrations accumulated by R. diobovata and R. babjevae were greater than 20% dry cell weight (dcw), and the major fatty acid components consisted of palmitic acid, oleic acid and linolenic acid. The highest concentration of total fatty acids in biomass were present during the late of stationary phase were 486.3 mg/g dcw for R. diobovata at 120 h pi, and 243.9 mg/g dcw for R. babjevae at 144 h pi. Both R. diobovata and R. babjevae produced high concentrations of torularhodin, and low amounts of torulene and γ-carotene. Total carotenoid concentrations in R. diobovata biomass were 31.5 mg/g dcw at 120 h pi and 43.1 mg/g dcw at 96 h pi for R. babjevae. The dcw accumulations of carotenoids by R. diobovata and R. babjevae were significantly greater than those reported for other carotenogenic Rhodotorula and Rhodosporidium strains.

Characterization and Prospective Applications of the Exopolysaccharides Produced by Rhodosporidium babjevae

Purpose: 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. This study aimed to characterize the EPSs from Rhodosporidium babjevae (ATCC 90942 and IBRC-M 30088) as well as to evaluate their possible antioxidant, emulsifying and antiproliferative activities. Methods: Rhodosporidium babjevae 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, water holding capacity and emulsifying activity of EPSs were evaluated. In vitro, antioxidant activity was investigated against DPPH, superoxide and hydroxyl radicals. Finally the EPSs consequence on the cell proliferation of human breast adenocarcinoma (MCF-7) and Madin-Darby canine kidney (MDCK) cell lines was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. Results: R. babjevae excreted 1.6±0.2 g/L of the EPSs. The EPSs had three fractions with molecular weights of 1.02 ×10⁶ , 5×10⁵ and 2×10⁵ Da. Mannose and glucose were found as the main monosaccharides of the EPSs (84:16 mol%, respectively). The EPSs exhibited emulsifying activity on sun flower oil. The scavenging activities were found to be dose-dependent and higher than hyaluronic acid. Significant difference among the EPSs treatments on the proliferation of MCF-7 and MDCK cell lines was not observed (P>0.05). Conclusion: These results show the interesting potential of the EPSs from R. babjevae as biocompatible compounds for using in food and pharmaceutical fields.