The 6th Annual CNPD (Centre for Natural Products Discovery at LJMU) Conference, Liverpool, İngiltere, 23 - 26 Haziran 2025, (Yayınlanmadı)
In this study, the exopolysaccharide
(EPS) production of Rhodotorula
dairenensis, isolated from hypersaline environments (Acıgöl, Turkey), was
investigated. EPS production was optimized using the Box-Behnken experimental
design. The EPS, partially purified via a dialysis membrane, were analyzed for
total carbohydrate and protein content, as well as the presence of uronic acid.
Structural and functional group analyses were conducted using NMR and FT-IR,
while surface morphology and elemental composition were examined using SEM-EDS.
The antioxidant activity was determined using the DPPH method, while the
cytotoxic activity of the EPS was assessed using the MTT method in the HaCaT
(keratinocyte) cell line. The viability of HaCaT cells was studied at
concentrations ranging from 61.5 to 125 μg/mL.
It was determined through the
halotolerance test that Rhodotorula
dairenensis is a halotolerant fungus adapted to extreme environments with
high salt concentrations. By optimizing the medium conditions for EPS
production, yields were approximately six times higher than those obtained
under non-optimized conditions (2.61 g/L). The obtained EPS were partially
purified by dialysis and further analyzed, revealing that the EPS contained
51.1% carbohydrate, 0.047% protein, and 0.17% uronic acid, respectively. The
polysaccharide structure, characterized by β-configuration linked via
glycosidic bonds, was identified through FT-IR and NMR analyses. Surface
morphology and elemental composition, including sulfur (indicative of sulfate
groups), were detected through SEM-EDS analysis. The IC50 value for
cytotoxic activity, reflecting 50% cell viability, was found to be 295 μg/mL.
The antioxidant activity exhibited an IC50 value at an EPS
concentration of 1 mg/mL. The structural properties of the obtained EPS, along
with its demonstrated antioxidant and cytotoxic activities, suggest that this
compound may be considered a potential biomaterial for industrial applications.