This review proposes a new bioremediation method based on the diverse functionalities of algae. A greenway for cleansing wastewater is more ecologically friendly and environmentally sustainable than prior methods with other bacteria. New bioremediation technology employing algae and cyanobacteria for the removal of a wide range of organic contaminants is reasonable and has great potential. The prevalence of organic contaminants in aquatic habitats may endanger the health and well-being of several marine creatures. Agriculture, industry, and household trash are just a few of the human-caused sources of organic pollutants that contaminate waterways around the world. Before wastewater can be released into waterways, it must be cleaned. Algae-based wastewater treatment systems are becoming increasingly popular because of their environmental sustainability and lack of secondary pollutants. According to the kind of pollutant, the physicochemical properties of wastewater, and the algal species, algae and cyanobacteria can absorb and accumulate a wide spectrum of organic pollutants at different rates. In addition, phytoremediation is a cost-effective alternative to conventional treatments for degrading organic contaminants. Phycoremediationally produced algal biomass may also be an important part of the bioenergy value chain. This article focuses on microalgae and cyanobacteria species, which may remove many organic contaminants from water systems.

Red Seaweed “Rhodophyta” are an important group of macroalgae that include approximately 7000 species. They are a rich source of structurally diverse bioactive constituents, including protein, sulfated polysaccharides, pigments, polyunsaturated fatty acids, vitamins, minerals, and phenolic compounds with nutritional, medical, and industrial importance. Polysaccharides are the main components in the cell wall of red algae and represent about 40–50% of the dry weight, which are extensively utilized in industry and pharmaceutical compounds, due to their thickening and gelling properties. The hydrocolloids galactans carrageenans and agars are the main red seaweed cell wall polysaccharides, which had broad-spectrum therapeutic characters. Generally, the chemical contents of seaweed are different according to the algal species, growth stage, environment, and external conditions, e.g., the temperature of the water, light intensity, nutrient concentrations in the ecosystem. Economically, they can be recommended as a substitute source for natural ingredients that contribute to a broad range of bioactivities like cancer therapy, anti-inflammatory agents, and acetylcholinesterase inhibitory. This review touches on the main points of the pharmaceutical applications of red seaweed, as well as the exploitation of their specific compounds and secondary metabolites with vital roles.

Ulvan is a sulfated heteropolysaccharide present in the cell wall of Ulva species with a unique structure and biological potential used in various fields. Chemical characterization was carried out to determine the structure of ulvan from Ulva fasciata Delile collected from Eastern Harbor, Alexandria coast, Egypt. Ulva contains 31.5% carbohydrate with a total ulvan content of 43.66% of total carbohydrate (13.75 g/100 g DW) and sulfate content of 20.45% of ulvan. FTIR spectrum presented signals of the sulfate ester (C–O–S) and sulfate groups (S=O), typical for ulvan. GC–MS revealed that ulvan was mainly composed of rhamnose and fucose. ¹H-NMR spectra of ulvan showed identical behavior of monosaccharides nature with peaks characteristic of sulfated polysaccharides at 3.2–5.3 ppm region. Scanning electron micrographs (SEM) demonstrated amorphous architecture, and the sulfated nature of polysaccharides was emphasized by EDX analysis. The extracted ulvan showed significant antimicrobial activity against human and fish pathogens as well as antifouling bacteria with minimum inhibitory concentrations (MIC) of 8 µg/mL. The extracted ulvan exhibited potent antioxidant activity with a scavenging effect of 84.93% for 2,2-diphenyl-1-picrylhydrazy free radical (DPPH). Moreover, it showed anti-arthritic properties for the first time with a maximum inhibition of 86.04% with IC₅₀ of 43.21%, indicating their potential value for the health and food industry.

Introduction: Brown seaweeds are excellent sources of bioactive molecules with a wide range of pharmacological effects, whose content can vary depending on several factors, including the origin and the environment in which the algae grow.Methods: This study aimed to estimate 19 compounds regarding primary and secondary metabolites of eight brown macroalgal species from a clean Egyptian Red Sea coast. A proximate analysis, pigment, phenolic compounds, and vitamin contents were determined. In addition, the energy content and antioxidant activity were estimated to explore the potential application of algae as functional foods to encourage the species’ commercialization.Results: Based on the chemical composition, Polycladia myrica was the most valuable species, with a comparatively high protein content of 22.54%, lipid content of 5.21%, fucoxanthin content of 3.12 μg/g, β-carotene content of 0.55 mg/100 g, and carbohydrate content of 45.2%. This species also acts as a great source of vitamin C, flavonoids, tannins, phenol content and total antioxidant capacity.Discussion: The antioxidant activity of the selected algae indicated that its phenol, vitamin and pigment contents were powerful antioxidant compounds based on the structure–activity relationships. This result was verified by the strong correlation in statistical analysis at the 95% confidence level. From a worldwide perspective and based on the obtained results, these brown species may be reinforced as an essential line in future foods.