Extracellular biopolymers produced by Dictyosphaerium family - Chemical and immunomodulative properties.

Many microalgal species produce a wide range of highly-value products which are interesting for biotechnological applications. Cultivation of microalgal species Dictyosphaerium pulchellum and Dictyosphaerium tetrachotomum, strains Růžicka and Fott resulted yields of 0.2, 0.7 and 1.8 g/L of extracellular biopolymers (EPSs), respectively. All biopolymers were shown to be anionic proteoglycans. The sugar composition analyses of all EPSs showed high contents of hexoses and the presence of partially methylated monosaccharide residues, i.e. hexoses, and deoxy hexoses. The dominant sugar component of all EPSs was found to be galactose. Extracellular microalgal biopolymers were subjected to immunobiological and immunotoxicological evaluation using murine melanoma cancer cells B16, murine fibroblast cell line NIH-3T3, murine macrophages cell line RAW 264.7 and skin construct EpiDerm™ (EPI-200). The EPSs exerted the antiproliferative effectivity; treatment of EPS induced proinflammatory cytokines TNF-α, IL-6, IL-12, IL-1β and IL-17, also engaged in anti-cancer immunity. Immunotoxicological studies revealed their non-toxic character and safe application on EpiDerm™.