Search results for "algae"

Assessment of cross-flow filtration as microalgae harvesting technique prior to anaerobic digestion: Evaluation of biomass integrity and energy demand

2018

[EN] In the present study, the effect of cross-flow filtration (CFF) on the overall valorization of Chlorella spp. microalgae as biogas was assessed. The effect of CFF on microalgae cell integrity was quantified in terms of viability which was correlated with the anaerobic biodegradability. The viability dropped as the biomass concentration increased, whereas anaerobic biodegradability increased linearly with the viability reduction. It was hypothesized that a stress-induced release and further accumulation of organic polymers during CFF increased the flux resistance which promoted harsher shear-stress conditions. Furthermore, the volume reduction as the concentration increased entailed an …

Biodiesel via in situ wet microalgae biotransformation: Zwitter-type ionic liquid supported extraction and transesterification

2017

The production of biodiesel derived from microalgae is among the most forthcoming technologies that provide an ecologic alternative to fossil fuels. Herein, a method was developed that enables the direct extraction and conversion of algal oil to biodiesel without prior isolation. The reaction occurs in aqueous media catalyzed by immobilized Candida antarctica lipase B (Novozyme 435). Zwitter-type ionic liquids were used as cocatalyst to improve the selectivity and reactivity of the enzyme. In a model reaction with sunflower oil, 64% biodiesel was obtained. Applying this method to a slurry of whole-cell Chlorella zof ingiensis in water resulted in 74.8% of lipid extraction, with 27.7% biotra…

Molecular phylogeny and ultrastructure of the lichen microalga Asterochloris mediterranea sp. nov. from Mediterranean and Canary Islands ecosystems

2015

The microalgae of the genus Asterochloris are the preferential phycobionts in Cladonia, Lepraria and Stereocaulon lichens. Recent studies have highlighted the hidden diversity of the genus, even though phycobionts hosting Cladonia spp. in Mediterranean and Canarian ecosystems have been poorly explored. Phylogenetic analyses were made by concatenation of the sequences obtained with a plastid -LSU rDNA- and two nuclear -ITS rDNA and actin- molecular markers of the phycobionts living in several populations of Cladonia convoluta-C. foliacea complex, C. rangiformis and C. cervicornis species widely distributed in these areas in a great variety of substrata and habitats. A new strongly supported …

Palaeoecology of non marine algae and stromatolites: Permian of France and adjacent countries

1999

Abstract Some Permian, continental basins from Algeria, Morocco, France, Italy, Germany and Poland reveal algal remains and stromatolites, mainly during Lower Permian, but also during Middle and Upper Permian. The algae belong to 8 morphogenera and 12 morphospecies. Two species are new. The taxonomic attributions are difficult, even if some species resemble living species. The algae make unorganized masses, or laminated builtups (stromatolites, oncolites, oolites). Algal masses and stromatolites are contained in fluviatile sediments (active or abandoned channels) and lacustrine deposits (playas, ephemeral lakes shorelines, lakes several meters or decameters deep). Considering the sedimentol…

Translocation of Cations During Sorption of Copper in the System Solution - Algae (Spirogyra sp.)/Translokacja Kationów Podczas Procesu Sorpcji Miedz…

2014

Zbadano kinetykę procesu sorpcji kationów miedzi w glonach Spirogyra sp. oraz towarzyszące mu procesy sorpcji kationów wodorowych i procesy uwalniania do roztworu kationów związanych w glonach: Na+, Mg2+, K+ i Ca2+. Stwierdzono, że w układzie statycznym, przy stałym stosunku masy glonów do objętości roztworu, procesy te zachodzą równocześnie, przy czym należy przypuszczać, że ilość uwalnianych soli ma wpływ na parametry heterofazowej równowagi wymiany jonowej. W warunkach prowadzenia eksperymentu ilość uwolnionych kationów była blisko 10-krotnie większa niż ilość kationów sorbowanych. Porównano parametry równowagi wyznaczone z modelu reakcji pseudo-drugiego rzędu z parametrami uzyskanymi po…

Use of algae in active biomonitoring of Surface waters

2014

Przeprowadzono badania biomonitoringowe trzech zbiorników retencyjnych położonych na terenie województwa opolskiego (południowa Polska): Zbiornika Turawa, Zbiornika Nysa i Zbiornika Otmuchów. W glonach słodkowodnych Spirogyra sp. i morskich Palmaria palmata (Linnaeus) Weber & Mohr, eksponowanych w badanych wodach, oznaczono metodą absorpcyjnej spektrometrii atomowej (AAS) przyrosty stężeń: Mn, Fe, Cu, Zn, Cd i Pb. W wodach oznaczano także pH, konduktywność oraz stężenie Mn i Fe. Stężenia Cu, Zn, Cd i Pb w badanych wodach były mniejsze od granicy oznaczalności metody. Badania prowadzono od czerwca do lipca 2014 r. Wskazano na różnice w przyrostach stężeń metali ciężkich w próbkach glonów eks…

Patrones de selección de microalgas en comunidades de líquenes terrícolas en biocostras

2020

Las costras biológicas de los suelos (biocostras, CBS) están constituidas por una combinación de organismos, tanto fotoautótrofos como heterótrofos, que viven dentro o sobre la superficie de los suelos, los cuales, con sus interacciones y actividades, generan una capa conjunta con las partículas del sustrato. Los líquenes, debido a la complejidad de sus simbiosis son capaces de colonizar estos hábitats adversos para otros vegetales, gracias a sus adaptaciones ecofisiológicas. Las biocostras dominadas por líquenes son muy abundantes en los claros de los matorrales y pastizales que se desarrollan en los territorios yesíferos. Su diversidad, participación en los ciclos biogeoquímicos y potenci…

Selezione dell’habitat in quattro specie ittiche criptobentoniche nell’infralitorale superiore di coste rocciose in Mediterraneo

2010

The seaweeds <i>Fucus vesiculosus</i> and <i>Ascophyllum nodosum</i> are significant contribu…

2013

Abstract. Based on the results of a pilot study in 2007, which found high mixing ratios of molecular iodine (I2) above the intertidal macroalgae (seaweed) beds at Mweenish Bay (Ireland), we extended the study to nine different locations in the vicinity of Mace Head Atmospheric Research Station on the west coast of Ireland during a field campaign in 2009. The mean values of I2 mixing ratio found above the macroalgae beds at nine different locations ranged from 104 to 393 ppt, implying a high source strength of I2. Such mixing ratios are sufficient to result in photochemically driven coastal new-particle formation events. Mixing ratios above the Ascophyllum nodosum and Fucus vesiculosus beds …

Organic solvent-soluble contents of nickel and cobalt in some algae

1990

In pursuit of our work on metal contents of lipid fractions isolated from plant material, we now show by means of highly sensitive analytical methods that nickel and cobalt are also present in organic extracts of algae in detectable amounts