Molecular and rheological characterization of different cell wall fractions of Porphyridium cruentum

Abstract

Cell wall related polysaccharides of the red microalga Porphyridium sp. were shown to be a promising source of new sustainable thickening agents. Isolated extracellular polysaccharides (EPS) consisted of high molecular weight polymers, showing a higher intrinsic viscosity compared to several commercially used hydrocolloids. Aqueous solutions of EPS (2% w/w) were characterized by substantial viscosities and weak gel behavior. Even though the extracted water soluble cell wall polysaccharides exhibited the same monosaccharide profile as EPS (composed of galactose, glucose, xylose and glucuronic acid), a lower molecular weight and intrinsic viscosity was observed for this fraction, resulting in poor rheological properties. Therefore, it was hypothesized that the physicochemical properties were related with a different molecular structural organization of these monosaccharides and sulfate groups. The main challenge for commercialization of extracellular polysaccharides of Porphyridium sp. remains the purification of these fractions to obtain polysaccharide extracts with low protein and salt contents.

Growth and Biochemical Composition of Porphyridium purpureum SCS-02 under Different Nitrogen Concentrations

“…P . purpureum can secrete EPS, the average molecular weight of which reaches 1.4 × 10 6 Da–1.7 × 10 6 Da [3]. EPS is considered an optimal ingredient in cosmetics because of its excellent moisturising properties.…”

“…Porphyridium purpureum is a species of marine red algae in the Porphyridiophyceae family. It has received great attention in recent years because of its potential to produce B-phycoerythrin (B-PE), long chain polyunsaturated fatty acids (LC-PUFAs) and exopolysaccharides (EPS) which are excellent feedstock for food, nutraceuticals and pharmaceuticals [1,2,3]. However, to date, large-scale cultivation and commercial application of P .…”

“…B-PE is one of the most well-known pigment-protein complexes; limitation of nitrogen can significantly inhibit the synthesis of B-PE, while sufficiency of nitrogen can substantially enhance the synthesis of B-PE [12]. EPS is a type of negatively charged sulphated polysaccharide, the average molecular weight of which ranges from 1.4 × 10 6 to 1.7 × 10 6 Da [3]. Under nitrogen-sufficient conditions, P .…”

Potential of Exopolysaccharide from Porphyridium marinum to Contend with Bacterial Proliferation, Biofilm Formation, and Breast Cancer

“…The work of [11] on Porphyridium sp. EPS could be cited in this context, who also suggested the presence of aggregates, as well as a more recent study on Porphyridium cruentum [12]. Such large aggregates can be the consequence of hydrophobic associations (the presence of esterified sugar or amphiphilic proteins), hydrogen bonds or complexes between polysaccharides and/or proteins.…”

“…This result could be correlated to the high aggregation tendency showed in a diluted regime (SEC/MALLS/Visco/DRI measurements). Some papers described rheological behavior of microalgae EPS, including from Porphyridium species (P. cruentum [12], P. sordidum and P. purpureum [24]), but all were conducted at greater concentrations than in the present study (0.125% or more), leading to difficulties in comparing viscosity values. However, they also observed a shear thinning behavior [12,23,25,26].…”