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The biosorption of lead(II), cadmium(II) and nickel(II) ions from aqueous solution by Spirulina platensis was studied as a function of time, concentration, temperature, repetitive reactivity, and ionic competition. The kinetic results obeyed well the pseudo second-order model. Freundlich, Dubinin Radushkevich and Temkin isotherm models were applied in describing the equilibrium partition of the ions. Freundlich isotherm was applied to describe the design of a single-stage batch sorption system. According to the thermodynamic parameters such as G• , H • and S• calculated, the sorption process was endothermic and largely driven towards the products. Sorption activities in a three metal ion system were studied which indicated that there is a relative selectivity of the biosorbent towards Pb 2+ ions. The measurements of the repetitive reusability of S. platensis indicated a large capacity towards the three metal ions.

The present study was conducted to evaluate the antioxidant and antimicrobial activity of methanol, dichloromethane and hexane extracts, as well as the essential oils of brown algae (Phaeophyta) Colpomenia sinuosa, Dictyota dichotoma, Dictyota dichotoma var. implexa, Petalonia fascia and Scytosiphon lomentaria. The essential oil of the macroalgae was obtained by steam distillation and analyzed by GC and GC/MS. The antioxidant activity of the algal extracts was determined using the procedures of inhibition of ?-carotene bleaching and ABTS+ methods. The antioxidant effects of the extracts were compared with those of commercial antioxidants, such as butylated hydroxytoluene (BHT), butylated hydroxyanisol (BHA) and ?-tocopherol. The hexane extracts of D. dichofoma var. implexa had a higher phenolic content than the other extracts. The dichloromethane extract of S. lomentaria was found to be more active in the decolorization of ABTS+ than the other extracts and generally the dichloromethane extracts were more active than the methanol and hexane extracts. Antimicrobial activities of the extracts were assessed against Gram (+) and Gram (-) bacteria and one yeast strain by the disk diffusion method. According to the results, the dichloromethane extracts generally showed more potent antimicrobial activity than the methanol and hexane extracts at concentrations 1.5 and 1.0 mg/disk.

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Marine organisms constitute approximately one-half of the total global biodiversity, being rich reservoirs of structurally diverse biofunctional components. The potential of cyanobacteria, micro- and macroalgae as sources of antimicrobial, antitumoral, anti-inflammatory, and anticoagulant compounds has been reported extensively. Nonetheless, biological activities of marine fauna and flora of the Aegean Sea have remained poorly studied when in comparison to other areas of the Mediterranean Sea. In this study, we screened the antimicrobial, antifouling, anti-inflammatory and anticancer potential of in total 98 specimens collected from the Aegean Sea. Ethanol extract of diatom Amphora cf capitellata showed the most promising antimicrobial results against Candida albicans while the extract of diatom Nitzschia communis showed effective results against Gram-positive bacterium, S. aureus. Extracts from the red alga Laurencia papillosa and from three Cystoseira species exhibited selective antiproliferative activity against cancer cell lines and an extract from the brown alga Dilophus fasciola showed the highest anti-inflammatory activity as measured in primary microglial and astrocyte cell cultures as well as by the reduction of proinflammatory cytokines. In summary, our study demonstrates that the Aegean Sea is a rich source of species that possess interesting potential for developing industrial applications.

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BACKGROUND The aim of this study was to investigate how the synergistic protocols between nutrient and light affect the cell growth, lipid content and fatty acid profile of Cylindrotheca closterium. Furthermore, the flow hydrodynamics of a laboratory scale internal loop air‐lift photobioreactor were investigated for the cultivation of C. closterium. RESULTS Maximum lipid productivity of 7.364 mg L−1 d−1, which corresponded to the maximum biomass production of 0.356 g L−1, was obtained in F/2 medium under light intensity of 56 μE m−2 s−1, highlighting the importance of high biomass accumulation for efficient lipid production. The most abundant saturated and monounsaturated fatty acids were pentadecanoic acid (C15:0) and palmitoleic acid (C16:1) which constituted 16–45% and 17–35% of total fatty acids for all growth conditions, respectively. CONCLUSION Palmitoleic acid was the dominant monounsaturated fatty acid, followed by oleic acid, whereas the most abundant saturated fatty acids were pentadecanoic acid and palmitic acid for C. closterium. Another notable outcome was that the fatty acid content increased in N‐free medium under low light intensity, while nitrogen starvation did not affect the fatty acid content under high light intensity. © 2015 Society of Chemical Industry