Cryptococcus laurentii growth and extracellular polysaccharide (EPS) production in bioreactor were studied. Biomass yield 14.3 g/L and EPS synthesis 4.3 g/L in 144 h of submerged cultivation were achieved. EPS synthesis and cell growth had different optima. For EPS formation, pH 3, 25 °C and low aeration (1 % < pO2 < 10 %) were advantageous, while cell growth optimum was at pH 6, 20 °C, and high aeration (pO2 > 30 %). As medium pH changed from pH 3 to pH 6, glucuronic acid (GluAc) content in EPS increased, while galactose, xylose, and glucose decreased. Twenty-five degrees Celsius was optimal for GluAc containing polysaccharide synthesis, while lower temperature (15 °C) increased glucose content in EPS. Aeration intensity and time of cultivation had little effect on EPS composition. Molecular mass distribution of raw C. laurentii EPS was determined by SEC-MALS as 1.352. The row EPS was composed of acidic glucuronoxylomannan for more than 85 %. In the in vivo experiments, EPS significantly improved excisional wound healing in healthy rats. The results suggest that C. laurentii EPS is a promising biotechnological product and an advanced material for application in wound management.
Polysaccharides account for more than 90% of the content of fungal cell walls, but the mechanism underlying the formation of the architecture of the cell walls, which consist of microfibrils embedded in an amorphous wall matrix, remains unknown. We used electron microscopy to investigate ten different fungal cell-wall polysaccharides to determine whether they could self-assemble into the fibrillar or amorphous component of fungal cell walls in a test tube without enzymes. The ultrastructures formed by precipitating β-1,3-glucan and β-1,6-glucan are different depending on the existence of branching in the molecule. Linear β-1,3-glucan and linear β-1,6-glucan precipitate into a fibrillar ultrastructure. Branched β-1,6-glucan, mannan and glycogen precipitates are amorphous. Branched β-1,3-glucan forms a fibrillar plus amorphous ultrastructure. Self-assembly among combinations of different linear and branched cell-wall polysaccharides results in an ultrastructure that resembles that of a yeast cell wall, which suggests that self-assembly of polysaccharides may participate in the development of the three-dimensional architecture of the yeast cell wall.
- MeSH
- beta-glukany chemie metabolismus MeSH
- buněčná stěna ultrastruktura MeSH
- elektronová mikroskopie MeSH
- fungální polysacharidy biosyntéza metabolismus MeSH
- mannany chemie metabolismus MeSH
- mikrofibrily metabolismus MeSH
- Saccharomyces cerevisiae metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
