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.

Brown macroalgae are a rich source of fucoidans with many pharmacological uses. This research aimed to isolate and characterize fucoidan from Dictyota dichotoma var. dichotoma (Hudson) J.V. Lamouroux and evaluate in vitro its antioxidant and antitumor potential. The fucoidan yield was 0.057 g/g algal dry wt with a molecular weight of about 48.6 kDa. In terms of fucoidan composition, the sulfate, uronic acid, and protein contents were 83.3 ± 5.20 mg/g fucoidan, 22.5 ± 0.80 mg/g fucoidan, and 26.1 ± 1.70 mg/g fucoidan, respectively. Fucose was the primary sugar component, as were glucose, galactose, mannose, xylose, and glucuronic acid. Fucoidan exhibited strong antioxidant potential that increased by more than 3 times with the increase in concentration from 0.1 to 5.0 mg/mL. Moreover, different concentrations of fucoidan (0.05–1 mg/mL) showed their ability to decrease the viability of Ehrlich ascites carcinoma cells in a time-dependent manner. These findings provided a fast method to obtain an appreciable amount of natural fucoidan with established structural characteristics as a promising compound with pronounced antioxidant and anticancer activity.

Effects of 12 heavy metals on growth of free and alginate-immobilized cells of the alga Pseudokirchneriella subcapitata were investigated. The tested metals ions include Al, As, Cd, Co, Cr, Cu, Hg, Se, Ni, Pb, Sr, and Zn. Toxicity values (EC₅₀) were calculated by graphical interpolation from dose-response curves. The highest to the lowest toxic metals are in the order Cd > Co > Hg > Cu > Ni > Zn > Cr > Al > Se > As > Pb > Sr. The lowest metal concentration (mg L⁻¹) inhibiting 50% (EC₅₀) of algal growth of free and immobilized (values in parentheses) algal cells were, 0.018 (0.09) for Cd, 0.03 (0.06) for Co, 0.039 (0.06) for Hg, 0.048 (0.050) for Cu, 0.055 (0.3) for Ni, 0.08 (0.1) for Zn, 0.2 (0.3) for Cr, 0.75 (1.8) for Al, 1.2 (1.4) for Se, 3.0 (4.0) for As, 3.3 (5.0) for Pb, and 160 (180) for Sr. Free and immobilized cultures showed similar responses to Cu and Se. The free cells were more sensitive than the immobilized ones. Accordingly, the toxicity (EC₅₀) of heavy metals derived only form immobilized algal cells might by questionable. The study suggests that batteries of alginate-immobilized algae can efficiently replace free algae for the bio-removal of heavy metals.

Economic viability of biodiesel production relies mainly on the productivity of biomass and microalgal lipids. In addition, production of omega fatty acids is favorable for human nutrition. Thus, enhancement of lipid accumulation with high proportion of omega fatty acids could help the dual use of microalgal lipids in human nutrition and biodiesel production through biorefinery. In that context, phytohormones have been identified as a promising factor to increase biomass and lipids production. However, nitrogen limitation has been discussed as a potential tool for lipid accumulation in microalgae, which results in simultaneous growth retardation. The present study aims to investigate the combined effect of N-depletion and 3-Indoleacetic acid (IAA) supplementation on lipid accumulation of the marine eustigmatophyte Nannochloropsis oceanica as one of the promising microalgae for omega fatty acids production. The study confirmed that N-starvation stimulates the lipid content of N. oceanica. IAA enhanced both growth and lipid accumulation due to enhancement of pigments biosynthesis. Therefore, combination effect of IAA and nitrogen depletion showed gradual increase in the dry weight compared to the control. Lipid analysis showed lower quantity of saturated fatty acids (SFA, 26.25%) than the sum of monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Under N-depletion, SFA decreased by 12.98% compared to the control, which recorded much reduction by increasing of IAA concentration. Reduction of SFA was in favor of PUFA, mainly omega-6 and omega-3 fatty acids which increased significantly due to IAA combined with N-depletion. Thus, the present study suggests a biorefinery approach for lipids extracted from N. oceanica for dual application in nutrition followed by biodiesel production.

Introduction: The trace element selenium is an essential micronutrient for the health of humans, animals, and microbesMany researchers have recently become interested in selenium nanoparticles (SeNPs) because of their biocompatibility, bioavailability, and low toxicity. Consequently, selenium nanoparticles are widely used in various biomedical applications and wastewater bioremediation due to their greater bioactivity. Green biosynthesis of nanoparticles is common and preferable nowadays.Methods: In this work, the selenium nanoparticles were synthesized using the brown seaweed Polycladia myrica aqueous extract and characterized using seven parameters, SEM, TEM, UV spectra, Zeta potential, EDX, X-ray differaction and FTIR, then examined for their cytotoxicity using PC-3 cells and normal mammalian cells from the African green monkey kidney (Vero) were used to test the effectiveness of the produced Polycladia myrica mediated selenium nanoparticles as an anticancer agent and antiviral activity against HAV HM175 (Hepatitis A), HSV-2 (Herpes simplex II), and Adenovirus strain 2.Results: The phycosynthesized nanoparticles exhibit antiviral activity (40.25 ± 2.61, 8.64 ± 0.82, and 17.39 ± 1.45%) against HAV-10, Adenovirus, and HSV-2, respectively. The IC50 values of the two cell types human prostate PC-3 and Vero were 123.51 ± 4.07 g/mL and 220.53 ± 6.89 g/ mL, respectively. The maximum inhibitory percent was 86.15 ± 2.31 against PC-3 cells. At the same time, at a concentration of 125 g/mL.Disscusion: This work showed that PoSeNPS have good antiviral activity against HAV-10 virus with an antiviral percent of 40.25%, despite weak antiviral activity against Adenovirus and HSV-2 with antiviral percent (8.64% and 17.39%), respectively. The cytotoxicity effect of these nanoparticles was determined against PC-3 with a maximum inhibitory percent of 80.53%. These nanoparticles have no hazardous effect against normal Vero cells as the viability percent was (78.39% and 49.23%) for Vero cells and PC-3 cells, respectively, at 125 μg/mL.

Four drugs, erythromycin, fluoxetine, naproxen and gemfibrozil, belonging to different therapeutic classes, were chosen to examine their toxicity to selected plankton organisms from different trophic levels: algae (Chlorella vulgaris and Ankestrodesmus falcatus), protozoa (Paramecium caudatum), rotifera (Brachionus calyciflorus) and cladocera (Daphnia longispina). LC50 values for three of the drugs were between 12 and 82 mg l−1, with algae and protozoans being most sensitive. Fluoxetine showed LC50 values between 40 and 830 µg l−1, algae again being most sensitive. The lower test concentrations of fluoxetine enhanced the growth rates of both B. calyciflorus and D. longispina. Even at low test concentrations, erythromycin decreased the growth rates of all the tested organisms. Paramecium caudatum was the species most sensitive to naproxen exposure. After 24 h, gemfibrozil had the least effect on all tested organisms. All the surviving tested organisms underwent oxidative stress to different degrees as a re...