Biorefinery practice for valorizing Mediterranean bloomed Pterocladia capillacea into valued and sustainable bioproducts with numerous green solicitations

Abstract

As a solution for ecosystem bioremediation from the gigantic red seaweed proliferation across the Mediterranean shorelines, this work investigates the effective utilization of Pterocladia capillacea to produce different esteemed and viable bioproducts. The nutritional composition of approximately 6.88 ± 0.31%, 20.15 ± 0.2%, 42.16 ± 0.3%, and 2.51 ± 0.05% (w:w) protein, fiber, carbohydrate, and lipid, respectively, promotes its application in the human food and animal fodder industries. Its N + P2O5 + K2O, undesirable heavy metals, organic carbon, and organic matter contents of 5.48 ± 0.07%, 2.82 ± 0.15 mg/kg, 16.11 ± 0.15%, and 27.71 ± 0.26% are all within the ranges allowed by the Egyptian standard for organic fertilizer. Its calorific value of 16.16 ± 0.5 MJ/kg and relatively low ash and heavy metals contents are in accordance with the international standards for primary solid biofuel. Its relatively high holocellulose content of 44 ± 0.5% (w/w) recommends its applicability in the liquid biofuels sector. Further, via a pioneering practice, a sequential, eco-friendly, and fully integrated bioprocess Pt. capillacea biomass is valorized into natural pigments of approximately 5.05 ± 0.05 mg/g total chlorophyll, 2.12 ± 0.05 mg/g carotenoids, phycobiliproteins of approximately 1.33 ± 0.05 mg/g phycocyanin, 3.07 ± 0.05 mg/g allophycocyanin, and 0.97 ± 0.05 mg/g phycoerythrin, hydrocolloids of approximately 28.21 ± 2.5% carrageenan and 20.46 ± 1.5% agar, and finally cellulose of approximately 20.15 ± 1.5%. Additionally, the extracted carrageenan proved an efficient antimicrobial action against pathogenic microorganisms that supports its use for water densification, food packing, and wound dressing.