Resumen de Blue bioprocess development of nutraceutics from marine red algae
Sarcopeltis skottsbergii is an endemic red alga species of the Southern Cone, with biliproteins as accessory pigments including R-phycoerythrin (R-PE). The production of S. skottsbergii is around 20,000 tons of dry alga per year. The evaluation of R-PE in a biorefinery model is still in the early stages in the field of algal biotechnology to be used in the food, pharmaceutical, cosmeceutical and nutraceutical industries. The objective of this Thesis is to present the current knowledge and the exploration of novel applications, encouraging the rational and integral utilization of this commercial specie. The Thesis is organized into six sections, covering information on the processing technologies for extraction (HPH and UAE) and protection (alginate/shellac by ionic gelation) of R-PE and fractions for functional foods and nutraceuticals, the in vitro and in vivo assessment of the biological activities, and alternative intensive production culture systems based on yellow light to saturate photosynthesis supplemented by blue light for R-PE accumulation. HPH method was the most efficient extraction method of R-PE. Furthermore, R-PE showed a positive correlation between the oxygen radical absorbance capacity (ORAC) in the best-selected extractions. An attractive non-aggressive extraction alternative with the biological activity of interest is suggested. From the residual supernatant generated by high-pressure homogenization, two soluble polysaccharides (neutral and acid fractions) were obtained with high biological activity. The acid polysaccharides, which had a relatively high sulfate content, exhibited significant antioxidant activity in superoxide radical assay (ABTS) and high anti-proliferative effects on melanoma (G-361), leukemia (U-937) and colon (HCT-116) carcinoma cells. The in vivo assay with zebrafish has shown a linear relationship between neutral and acid fractions concentration and growth retardation at 72 hpf mg-1 ml-1 with a LC50 of about 1.45 mg ml-1 and 1.25 mg ml-1, respectively. These results indicated that the in vitro antitumoral assays, in vivo model and antioxidant activities of the two polysaccharides may be related to the combined effects of sulfate or galactose contents.
The encapsulation of alginate/shellac reached an EE value of 97.5% and led to higher R-PE contents at the end of digestion compared with R-PE non-encapsulated, suggesting a protective role. From permeate streams, equivalent to the absorption of R-PE encapsulated, the bioavailability was 2.5 times significantly higher than R-PE non-encapsulated. A high selectivity index (> 10) was observed for the R-PE extract on the HCT-116 human colon cancer cell line. The alginate/shellac as a wall material and ionic gelation technology used may determine the release of the R-PE pigment at an intestinal site and their effect antiproliferative on health. Yellow light with the incidence of blue light as an interesting factor in the culture of red microalgae improves high-quality R-PE compound and maintained stable biomass productivity, to improve the quality of bioprocess production for nutraceutical industry. This Thesis complemented understanding the potential of algae for traditional and novel functional products.
