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A Strategy for the Sequential Recovery of Biomacromolecules from Red Macroalgae Porphyra umbilicalis Kützing

Wahlström, Niklas, Harrysson, Hanna, Undeland, Ingrid, Edlund, Ulrica
Industrial & engineering chemistry process design and development 2018 v.57 no.1 pp. 42-53
Porphyra, aluminum, arsenic, calcium, carrageenan, cellulose, chromatography, coasts, energy-dispersive X-ray analysis, fractionation, heavy metals, lead, macroalgae, magnesium, mercury, pectins, process design, protein content, proteins, scanning electron microscopy, sodium, spectroscopy, toxic substances, water solubility, Sweden
A nondestructive, multicomponent fractionation strategy has been developed to extract proteins and polysaccharides from the red macroalgae Porphyra umbilicalis collected along the west coast of Sweden and cultivated indoors under controlled conditions. First, a protein-rich fraction was extracted in an ice-cold alkaline solution. The overall protein content in Porphyra umbilicalis was estimated to be 30.6% of the dry weight, and out of that, 15.0% could be recovered. Water-soluble polysaccharides were then extracted from the insoluble residual fraction using sequential alkaline and acidic treatments at 90 °C for 4 h. Spectroscopic and chromatographic analyses of the polysaccharide fractions show that high-molecular-weight carrageenans were obtained from the alkaline extraction and a galactose-rich pectin substance was obtained from the acidic extraction. The insoluble fraction remaining after all extraction steps was rich in cellulose. An elemental analysis of Porphyra umbilicalis via scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM-EDS) showed the presence of C, O, Na, Ca, Mg, Al, Cl, and S. However, no heavy metals or other toxic elements, such as Pb, Hg, and As, were found.