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  • 1.
    Bigler, Christian
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Gälman, Veronika
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Renberg, Ingemar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Numerical simulations suggest that counting sums and taxonomic resolution of diatom analyses to determine IPS pollution and ACID acidity indices can be reduced2010Ingår i: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 22, nr 5, s. 541-548Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Implementation of the European Union Water Framework Directive and associated national guidelines has emphasized the value of using biota, such as epilithic diatoms in streams, as indicators of water quality. However, guidelines for evaluating diatom samples have been established without explicitly evaluating their statistical robustness. We used epilithic diatom samples from 73 streams in northern Sweden and simulated the effects of variations in the counting sum size and taxonomic resolution of classifications for two indices indicating pollution (Indice de Polluo-sensibilité Spécifique, IPS) and acidity (acidity index for diatoms, ACID). Instead of the stipulated 400, we found that a count sum of 40 diatom valves for 50 streams, and 80 valves for 60 streams, would have been sufficient to obtain the same IPS index classification. The ACID index is more sensitive to count sum reductions, since the same classification would only have been obtained for 12 streams with 40 counted diatom valves or 24 streams with a count of 80 valves. Excluding rare taxa had negligible effects on the IPS and ACID indices. Excluding taxa occurring with less than 1.0% frequency affected the IPS classification of only one stream, and excluding taxa with less than 2.5% and 5.0% frequencies affected those of just one and no streams, respectively. The ACID index was affected for none, five, and 12 streams, respectively. At least in relatively unpolluted regions such as northern Sweden, our simulations suggest that a simplified methodological approach with site-specific counting sum sizes and reduced taxonomical resolution could be adopted, taking into account the way sites are classified in relation to established class boundaries. The simplified method is a step forward in improving the cost efficiency for stream monitoring, as costs of diatom analysis to obtain identical IPS and ACID classifications of our streams could be reduced considerably. Before the simplified method can be widely adopted, further simulations including regions with a higher proportion of polluted streams are required.

  • 2.
    Ferro, Lorenza
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Valladolid, Spain.
    Colombo, Michela
    Posadas, Esther
    Funk, Christiane
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Muñoz, Raul
    Elucidating the symbiotic interactions between a locally isolated microalga Chlorella vulgaris and its co-occurring bacterium Rhizobium sp. in synthetic municipal wastewater2019Ingår i: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 31, nr 4, s. 2299-2310Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Co-cultivation of microalgae and bacteria during municipal wastewater treatment can boost carbon and nutrient recovery as a result of their synergistic interactions. The symbiotic relationships between the locally isolated microalga Chlorella vulgaris and the bacterium Rhizobium sp., co-isolated from municipal wastewater, were investigated batchwise under photoautotrophic, heterotrophic, and mixotrophic conditions in a synthetic municipal wastewater medium. During photoautotrophic growth in BG11 medium, photosynthetic algal oxygenation and organic carbon production supported bacterial activity but no significant beneficial effects on microalgal growth were observed. In synthetic wastewater, a twofold higher biomass concentration was achieved in the axenic algal culture compared with the co-culture under heterotrophic conditions, suggesting a competition for nutrients. A comparable carbon removal was observed in all cultures (83–79% TOC), but a faster nitrogen consumption (59% TN) and complete phosphate assimilation (100% TP) was only achieved in the co-culture. A positive synergistic relationship was found under mixotrophic conditions, clearly supported by an in situ O2/CO2 exchange between the microorganisms. This mutualism led to a threefold higher biomass production with a 13-fold higher fatty acid content compared with the axenic algal culture, as well as a superior wastewater treatment performance (+ 58% TOC, + 41% TN and + 44% TP). The co-cultivation of C. vulgaris and Rhizobium is therefore suggested as a potential microbial consortium for a cost-efficient biomass generation during municipal wastewater reclamation, especially under mixotrophic conditions.

  • 3. Gentili, Francesco G.
    et al.
    Fick, Jerker
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Algal cultivation in urban wastewater: an efficient way to reduce pharmaceutical pollutants2017Ingår i: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 29, nr 1, s. 255-262Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The purpose of this study was to investigate whether pharmaceutical pollutants in urban wastewater can be reduced during algal cultivation. A mixed population of wild freshwater green algal species was grown on urban wastewater influent in a 650 L photobioreactor under natural light and with the addition of flue gases. Removal efficiencies were very high (> 90 %), moderate (50-90 %), low (10-50 %), and very low or non-quantifiable (< 10 %) for 9, 14, 11, and 18 pharmaceuticals, respectively, over a 7-day period. High reduction was found in the following pharmaceuticals: the beta-blockers atenolol, bispropol, and metoprolol; the antibiotic clarithromycine; the antidepressant bupropion; the muscle relaxant atracurium; hypertension drugs diltiazem and terbutaline used to relive the symptoms of asthma. Regression analysis did not detect any relationship between the reduction in pharmaceutical contents and light intensity reaching the water surface of the algal culture. However, the reduction was positively correlated with light intensity inside the culture and stronger when data collected during the night were excluded. Algae cultivation can remove partially or totally pharmaceutical pollutants from urban wastewater, and this opens up new possibilities for treating urban wastewater.

  • 4. Kahlert, Maria
    et al.
    Albert, Raino-Lars
    Anttila, Eeva-Leena
    Bengtsson, Roland
    Bigler, Christian
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Eskola, Tiina
    Gälman, Veronika
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Gottschalk, Steffi
    Herlitz, Eva
    Jarlman, Amelie
    Kasperoviciene, Jurate
    Kokociński, Mikołaj
    Luup, Helen
    Miettinen, Juha
    Paunksnyte, Ieva
    Piirsoo, Kai
    Quintana, Isabel
    Raunio, Janne
    Sandell, Bernt
    Simola, Heikki
    Sundberg, Irene
    Vilbaste, Sirje
    Weckström, Jan
    Harmonization is more important than experience—results of the first Nordic–Baltic diatom intercalibration exercise 2007 (stream monitoring)2009Ingår i: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 21, nr 4, s. 471-482Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The goal of this study was a harmonization of diatom identification and counting among diatomists from the Scandinavian and Baltic countries to improve the comparison of diatom studies in this geographical area. An analysis of the results of 25 diatomists following the European standard EN 14407 during an intercalibration exercise showed that a high similarity was achieved by harmonization and not because of a long experience with diatoms. Sources of error were wrong calibration scales, overlooking of small taxa, especially small Navicula s.l., misidentifications (Eunotia rhomboidea was mistaken for Eunotia incisa) and unclear separation between certain taxa in the identification literature. The latter was discussed during a workshop with focus on the Achnanthes minutissima group, the separation of Fragilaria capucina var. gracilis from F. capucina var. rumpens, and Nitzschia palea var. palea from N. palea var. debilis. The exercise showed also that the Swedish standard diatom method tested here worked fine with acceptable error for the indices IPS (Indice de Polluo-sensibilité Spécifique) and ACID (ACidity Index for Diatoms) when diatomists with a low similarity (Bray–Curtis <60%) with the auditor in at least one of the samples are excluded.

  • 5. Leyton, A.
    et al.
    Pezoa-Conte, R.
    Mäki-Arvela, P.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Lienqueo, M. E.
    Improvement in carbohydrate and phlorotannin extraction from Macrocystis pyrifera using carbohydrate active enzyme from marine Alternaria sp. as pretreatment2017Ingår i: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 29, nr 4, s. 2039-2048Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The commercial importance of brown seaweed has been increasing over the past decade, especially due to industries interested in the extraction of phycocolloids and, more recently, of polyphenol compounds such as phlorotannins. The objective of this work was to optimize the extraction conditions of carbohydrates and phlorotannins from Macrocystis pyrifera, evaluated enzymatic pretreatment and different parameters of extraction using design of experiment. The optimal conditions upon extraction of the carbohydrates and phlorotannins were determined by means of a pretreatment protocol taking advantage on a carbohydrate active enzyme, followed by an alkaline hydrolysis with 0.5 N NaOH at 100 °C, 180 min, and S/L ratio of 1/20. In order to extract the carbohydrates, the best conditions found for the pretreatment procedure were 37 °C, pH 7.0 for 24 h, and a S/L ratio of 1/10, giving an extraction yield (EY) of 89.67 ± 12.3 wt.%. In turn, for the extraction of phlorotannins, the best conditions identified in terms of the pretreatment were 25 °C, pH 7.0 for 36 h, and a S/L ratio of 1/20, thus giving a yield (EY) of 2.14 ± 0.25 wt.%. Statistical analysis of both processes revealed a maximum EY of 91.24 wt.% for carbohydrates and 3.31 wt.% EY for phlorotannins.

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