Potential of fibrous adsorbents for the binding and characterization of Porphyridium purpureum bioactive polysaccharides

Abstract

BACKGROUND: Complex polysaccharides are important in the pharmaceutical industry, yet, due to their large molecular weight and reduced charges, their purification is a highly demanding process that requires binding matrices with unique properties. This work demonstrates for the first time that complex polysaccharides biosynthesized by microalga Porphyridium purpureum can be adsorbed onto Q fibrous anion exchangers. RESULTSWhen the polysaccharides were characterized, the extent of sulfation was higher in native polysaccharides than in ethanol-or alkali-extracts. The zeta potentials increased with increasing pH and the highest charge was observed at pH 8, while the Z-average diameters of the polysaccharide at pH 6 were highest for alkali-extracts. Instead of pellicular resins, Q fibrous adsorbents were used to determine Langmuir thermodynamic properties and dynamic binding capacities. The parameters included static binding capacity and dissociation constant of 13.47 ± 1.02 mg g -1 and 0.141 ± 0.027 mg mL -1 , and 10 and 50% breakthrough capacities of 4.46 ± 0.22 and 5.51 ± 0.28 mg g -1 , respectively. The antiviral activity of the polysaccharides was demonstrated by minimizing bacteriophage lysis of Streptococcus thermophilus.CONCLUSION This work demonstrates that polysaccharide extraction can be optimized and the adsorption and desorption of a complex polysaccharide onto Q fibrous matrix is feasible. These parameters could be exploited for up-scaling of polysaccharides for nutraceutical and pharmaceutical applications. Primary recovery operations of sulfated polysaccharidesMicroalgae were pelleted by centrifugation at 3250 g and 4 • C for 45 min followed by addition of three parts of cold 99% ethanol to the microalgal supernatant. Likewise, polysaccharides were alkali extracted following the protocol of Miyajima and co-workers. 19 Both mixtures were shaken at 100 rpm for 10 min then kept at 4 • C for overnight extraction. The precipitates were separated from the aqueous phases by centrifugation as mentioned above. Pellets were resuspended in demineralized water, dialyzed through Spectra/Por regenerated cellulose membranes (MWCO, 12-14 kDa) overnight against double deionized water followed by lyophilization using an ALPHA 1-2 LD Plus (Martin Christ Gefriertrocknungsanlagen GmbH, Osterode am Harz, Germany). The ethanol-and alkali-extracted polysaccharides were designated 'Extract 1' and 'Extract 2', respectively.Determination of zeta potential and Z-average diameter of sulfated polysaccharide by light scattering P. purpureum polysaccharides were dissolved in 20 mmol L -1 citrate-phosphate buffer at pH 4, 5, 6, 7 and 8 to a concentration wileyonlinelibrary.com/jctb

Comparison of the Level and Mechanisms of Toxicity of Carbon Nanotubes, Carbon Nanofibers, and Silicon Nanotubes in Bioassay with Four Marine Microalgae

“…It was shown (Figure 1) that the carbon nanotubes sample CNT-2 having the most ordered structure had a lower influence on the growth-rate of P. purpureum as compared to the other carbon NPs having unordered structure and a relatively higher hydrophobicity. Therefore, based on inhibition of growth-rate of P. purpureum and low influence of carbon NPs (except CNT-2) on esterase activity and membrane potential, we can conclude that the main mechanism of toxic action of these samples on the red microalgae was a physical damage caused by adhesion of clusters of NPs with extracellular mucopolysaccharides of P. purpureum [79]. Almost no effect of carbon NPs on growth-rate of A. ussuriensis, H. akashiwo, and C. muelleri was probably caused by the lower mechanical interaction between microalgae cells and the NPs.…”

Comparison of the Level and Mechanisms of Toxicity of Carbon Nanotubes, Carbon Nanofibers, and Silicon Nanotubes in Bioassay with Four Marine Microalgae

“…It was shown (Figure 1) that the carbon nanotubes sample CNT-2 having the most ordered structure had a lower influence on the growth-rate of P. purpureum as compared to the other carbon NPs having unordered structure and a relatively higher hydrophobicity. Therefore, based on inhibition of growth-rate of P. purpureum and low influence of carbon NPs (except CNT-2) on esterase activity and membrane potential, we can conclude that the main mechanism of toxic action of these samples on the red microalgae was a physical damage caused by adhesion of clusters of NPs with extracellular mucopolysaccharides of P. purpureum [42]. Almost no effect of carbon NPs on growth-rate of A. ussuriensis, H. akashiwo, and C. muelleri was probably caused by the lower mechanical interaction between microalgae cells and the NPs.…”