Cetylpyridiniumbromide hydrate

The synthesis of Zr-doped
silica nanospheres was carried out using tetraethylorthosilicate (99%,
Sigma-Aldrich), zirconium propoxide (70% in 1-propanol, Sigma-Aldrich)
and zirconium oxychloride octahydrated (99%, Sigma-Aldrich). Cetylpyridinium
bromide hydrate (98%, Sigma-Aldrich), cyclohexane (99%, Sigma-Aldrich),
and 1-pentanol (99%, Sigma-Aldrich) were also utilized. Urea and hydrochloric
acid were purchased from VWR.
Gases used in the characterization
and catalytic processes were He (Air Liquide 99.99%), H₂ (Air Liquide 99.999%), N₂ (Air Liquide 99.9999%), and
N₂/O₂ (80/20 vol %).

The extraction of polysaccharides from P. cruentum was performed using the method proposed by Abdala-Díaz et al. (2010) [26 (link)] with minor modifications. Once the culture of P. cruentum reached the early stationary phase, centrifugation was performed at 4500 rpm for 10 min, and the supernatant was recovered for polysaccharides extraction. The polysaccharides were extracted by selective precipitation with 2% Cetylpyridinium bromide hydrate (w/v) (Cetavlon) (Sigma-Aldrich Ref: 285315). The precipitated sulfated polysaccharides were dissolved with 4 M NaCl (Sigma-Aldrich), centrifuged at 5000 rpm for 10 min and then flocculated with 96% (v/v) ethanol (Sigma-Aldrich). The final pellet was recovered and introduced into a dialysis membrane (Cellulose dialysis tube, Sigma-Aldrich) for overnight dialysis at low osmotic pressure (1M NaCl) and agitation at 4 °C. After dialysis, the entire membrane content was recovered and washed with 96% EtOH. Final centrifugation (4500 rpm, 2 min, at room temperature) was applied to recover the polysaccharides. The polysaccharides were then frozen at −80 °C in absolute ethanol for 24 h and lyophilized (Cryodos Lyophilizer, Telstar). The sulfated polysaccharide-enriched extract will hereinafter be referred to as “PcSPs”.