Search

Baltic seaweeds were used to obtain aqueous extracts (E) through changing initial pH of deionised water added to algal biomass (EpH3·H2O, EpH7·H2O, and EpH10·H2O) and through changing pH of the mixture of algae and deionised water (EpH3, EpH7, and EpH10). Algal extracts were characterized in terms of the concentration of polyphenols and micro- and macroelements. The highest concentration of polyphenols was determined in extract EpH3 and the lowest in extract EpH10·H2O. It was found that the obtained extracts had similar concentrations of elements (except EpH3). The phytotoxicity of algal extracts (0.5, 2.5, and 10%) was examined in the germination tests on Lepidium sativum. No phytotoxic effects were observed. It was found that they had beneficial effects on the cultivated plants (length and weight). The best biostimulant effect was observed in the groups treated with EpH3 (2.5%), EpH7 (2.5%), and EpH7 (10%). The dry weight of plants was similar in all the groups. Algal extract also improved the multielemental composition of plant. The greatest concentration of total chlorophyll in plants was obtained by using extract EpH10·H2O, 0.5%. These results proved that algal extracts have high potential to be applied in cultivation of plants. [ABSTRACT FROM AUTHOR]

The biomass of Vaucheria sessilis forms algal mats in many freshwaters. There is a need to find the method of algal biomass utilization. Vaucheria sessilis is a rich source of micro- and macronutrients and can be used as a soil amendment. In the paper, the elemental composition of enriched, via bioaccumulation process, macroalga was investigated. For this purpose, two independent techniques were used: scanning electron microscopy with an energy dispersive X-ray analytical system (SEMEDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The biomass was exposed to two microelemental solutions, with Cu(II) and Zn(II) ions. After two weeks of the experiment, macroalga accumulated 98.5mg of Zn(II) ions in 1 g of dry biomass and 68.9mg g-1 of Cu(II) ions. Micrographs performed by SEM proved that bioaccumulation occurred. Metal ions were bound on the surface and in the interior of cells. Mappings of all cations showed that in the case of the surface of biomass (biosorption), the elements constituted aggregations and in the case of the cross section (bioaccumulation) they were evenly distributed.Thealgal biomass with permanently bound microelements can find an application in many branches of the industry (feed, natural fertilizers, etc.). [ABSTRACT FROM AUTHOR]

Surface characterization and metal ion adsorption properties of Spirulina sp. and Spirulina maxima were verified by various instrumental techniques. FTIR spectroscopy and potentiometric titration were used for qualitative and quantitative determination of metal ion-binding groups. Comparative FTIR spectra of natural and Cu(II)-treated biomass proved involvement of both phosphoryl and sulfone groups in metal ions sorption. The potentiometric titration data analysis provided the best fit with the model assuming the presence of three types of surface functional groups and the carboxyl group as the major binding site. The mechanism of metal ions biosorption was investigated by comparing the results from multielemental analyses by ICP-OES and SEM-EDX. Biosorption of Cu(II), Mn(II), Zn(II), and Co(II) ions by lyophilized Spirulina sp. was performed to determine the metal affinity relationships for single- and multicomponent systems. Obtained results showed the replacement of naturally bound ions: Na(I), K(I), or Ca(II) with sorbed metal ions in a descending order of Mn(II) > Cu(II) > Zn(II) > Co(II) for single- and Cu(II) > Mn(II) > Co(II) > Zn(II) for multicomponent systems, respectively. Surface elemental composition of natural and metalloaded material was determined both by ICP-OES and SEM-EDX analysis, showing relatively high value of correlation coefficient between the concentration of Na(I) ions in algal biomass. [ABSTRACT FROM AUTHOR]