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  • 1.
    Figueroa, Daniela
    et al.
    Umeå University ; Umeå Marine Sciences Centre.
    Rowe, O. F.
    Umeå University ; University of Helsinki, Finland.
    Paczkowska, Joanna
    Umeå University.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Andersson, Agneta
    Umeå University ; Umeå Marine Sciences Centre.
    Allochthonous Carbon-a Major Driver of Bacterioplankton Production in the Subarctic Northern Baltic Sea2016In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 71, no 4, p. 789-801Article in journal (Refereed)
    Abstract [en]

    Heterotrophic bacteria are, in many aquatic systems, reliant on autochthonous organic carbon as their energy source. One exception is low-productive humic lakes, where allochthonous dissolved organic matter (ADOM) is the major driver. We hypothesized that bacterial production (BP) is similarly regulated in subarctic estuaries that receive large amounts of riverine material. BP and potential explanatory factors were measured during May-August 2011 in the subarctic Råne Estuary, northern Sweden. The highest BP was observed in spring, concomitant with the spring river-flush and the lowest rates occurred during summer when primary production (PP) peaked. PLS correlations showed that ∼60 % of the BP variation was explained by different ADOM components, measured as humic substances, dissolved organic carbon (DOC) and coloured dissolved organic matter (CDOM). On average, BP was threefold higher than PP. The bioavailability of allochthonous dissolved organic carbon (ADOC) exhibited large spatial and temporal variation; however, the average value was low, ∼2 %. Bioassay analysis showed that BP in the near-shore area was potentially carbon limited early in the season, while BP at seaward stations was more commonly limited by nitrogen-phosphorus. Nevertheless, the bioassay indicated that ADOC could contribute significantly to the in situ BP, ∼60 %. We conclude that ADOM is a regulator of BP in the studied estuary. Thus, projected climate-induced increases in river discharge suggest that BP will increase in subarctic coastal areas during the coming century.

  • 2.
    Mitter, Eduardo Kovalski
    et al.
    Sao Paulo State University, Brazil.
    Santos, Graziely Cristina
    Almeida, Erica Janaína Rodrigues
    Sao Paulo State University, Brazil.
    Morão, Luana Galvão
    Sao Paulo State University, Brazil.
    Rodrigues, Heide Dayane Prates
    Sao Paulo State University, Brazil.
    Corso, Carlos Renato
    Sao Paulo State University, Brazil.
    Analysis of Acid Alizarin Violet N Dye Removal Using Sugarcane Bagasse as Adsorbent2012In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 223, no 2, p. 765-770Article in journal (Refereed)
    Abstract [en]

    With the development of the textile industry, there has been a demand for dye removal from contaminated effluents. In recent years, attention has been directed toward various natural solid materials that are capable of removing pollutants from contaminated water at low cost. One such material is sugarcane bagasse. The aim of the present study was to evaluate adsorption of the dye Acid Violet Alizarin N with different concentrations of sugarcane bagasse and granulometry in agitated systems at different pH. The most promising data (achieved with pH 2.5) was analyzed with both Freundlich and Langmuir isotherms equations. The model that better fits dye adsorption interaction into sugarcane bagasse is Freundlich equation, and thus the multilayer model. Moreover, a smaller bagasse granulometry led to greater dye adsorption. The best treatment was achieved with a granulometry value lower than 0.21 mm at pH 2.50, in which the total removal was estimated at a concentration of 16.25 mg mL−1. Hence, sugarcane bagasse proves to be very attractive for dye removal from textile effluents.

  • 3.
    Ni, Gaofeng
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    When bioelectrochemical systems meet extremophiles, possibilities and challenges2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Extremophiles are microorganisms live and thrive in extreme environments that are harsh and hostile to most forms of life on earth (e.g. low pH, low temperature, high pH and high salinity). They have developed strategies to obtain nutrients and conserve energy to sustain life under these adverse conditions. Such metabolic capabilities are valuable to be exploit for industrial applications such as the remediation of environmental pollutions, which typically bring about extreme physicochemical conditions. The advancing technology bioelectrochemical systems can utilize the microbial metabolism to oxidize a substrate while simultaneously recover electrical energy or produce a useful product in an electrochemical set-up. It enables the remediation of pollutions, and its integration with extremophiles has opened up a wide range of possibilities to tackle various industrial waste streams with extreme conditions in an environmentally friendly manner. Inorganic sulfur compounds such as tetrathionate, thiocyanate and sulfide that originate from mining, metal refinery and petroleum industries are toxic and hazardous to the recipient water body and human health if discharged untreated. The remediation of these three compounds with bioelectrochemical systems that incorporates extremophiles was investigated in three separate studies of this thesis. 16S rRNA gene amplicon sequencing, metagenomics and metatranscriptomics are utilized to profile the microbial communities, and to understand their metabolic potential and states.

     

    Tetrathionate degradation with acidophilic microorganisms in microbial fuel cells at pH 2 was demonstrated in the first study of this thesis. Electricity was produced from the oxidation of tetrathionate, facilitated by the anodic microbiome. 16S rRNA gene amplicon sequencing showed that this community was dominated by members of the genera Thermoplasma, Ferroplasma, Leptospirillum, Sulfobacillus and Acidithiobacillus. Metagenomic analysis reconstructed genomes that were most similar to the genera Ferroplasma, Acidithiobacillus, Sulfobacillus and Cuniculiplasma. Together with metatranscriptomic analysis, it was indicated that this microbial community was metabolizing tetrathionate and other intermediate sulfur compounds via multiple pathways, the electrons released from oxidation were suggested to be transferred to the electrode via soluble electron shuttles. In addition, the Ferroplasma-like population in this study was suggested to be active in metabolising inorganic sulfur compounds and synthesizing soluble electron shuttles. Since characterized Ferroplasma species do not utilize inorganic sulfur compounds, the anodic compartment might have selected a novel Ferroplasma population.

     

    Next, thiocyanate degradation with psychrophilic microorganisms in microbial fuel cells at 8 °C was demonstrated for the first time. Electricity generation alongside with thiocyanate degradation facilitated by the anodic microbiome was observed. 16S rRNA gene amplicon sequencing and metatranscriptomics suggested that Thiobacillus was the predominant and most active population. mRNA analysis revealed that thiocyanate was metabolized primarily via the ‘cyanate’ degradation pathway; the resultant sulfide was oxidized; ammonium was assimilated; carbon dioxide was fixed as carbon source. It was also suggested by mRNA analysis that the consortium used multiple mechanisms to acclimate low temperature such as the synthesis of cold shock proteins, cold inducible proteins and molecular chaperones.

     

    Finally, sulfide removal with haloalkaliphilic microorganisms in microbial electrolysis cells operated at pH 8.8 to 9.5 and with 1.0 M sodium ion was investigated. The anodic microbiome was hypothesized to facilitate current generation by the oxidation of sulfide and of intermediate sulfur compounds to sulfate, which was supported by chemical analysis and microbial profiling. Dominant populations from the anode had 16S rRNA gene sequences that aligned within the genera Thioalkalivibrio, Thioalkalimicrobium, and Desulfurivibrio, which are known for sulfide oxidation. Intriguingly, Desulfurivibrio dominated the electrode-attached community, possibly enriched by the electrode as a selecting pressure. This finding suggested a novel role of this organism to carry out sulfide oxidation coupled to electron transfer to the electrode.

     

    These three studies demonstrated the possibilities of utilizing extremophilic bioelectrochemical systems to remediate various inorganic sulfur pollution streams. The advancing molecular microbiological tools facilitated the investigation towards the composition and metabolic state of the microbial community. Challenges remain in a more thorough understanding regarding the metabolism of extremophiles (e.g. sulfur metabolism and extracellular electron transfer) and better energy recovery in bioelectrochemical systems.

  • 4.
    Olofsson, Martin
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lindehoff, Elin
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Frick, Brage
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Svensson, Fredrik
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Legrand, Catherine
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Baltic Sea microalgae transform cement flue gas into valuable biomass2015In: Algal Research, ISSN 2211-9264, Vol. 11, p. 227-233Article in journal (Refereed)
    Abstract [en]

    We show high feasibility of using cement industrial flue gas as CO2 source for microalgal cultivation. The toxicity of cement flue gas (12-15% CO2) on algal biomass production and composition (lipids, proteins, carbohydrates) was tested using monocultures (Tetraselmis sp., green algae, Skeletonema marinoi, diatom) and natural brackish communities. The performance of a natural microalgal community dominated by spring diatoms was compared to a highly productive diatom monoculture S. marinoi fed with flue gas or air-CO2 mixture. Flue gas was not toxic to any of the microalgae tested. Instead we show high quality of microalgal biomass (lipids 20-30% DW, proteins 20-28% DW, carbohydrates 15-30% DW) and high production when cultivated with flue gas addition compared to CO2-air. Brackish Baltic Sea microalgal communities performed equally or better in terms of biomass quality and production than documented monocultures of diatom and green algae, often used in algal research and development. Hence, we conclude that microalgae should be included in biological solutions to transform waste into renewable resources in coastal waters. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  • 5.
    Sandhi, Arifin
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Stockholm university, Sweden.
    Greger, Maria
    Stockholm university, Sweden.
    Moss based constructed wetland system: is it possible to use aquatic moss (warnstorfia fluitans) for removal of as in an eco-friendly approach?2018In: Book of Abstracts: Linnaeus Eco-Tech 2018 / [ed] Yahya Jani, Jelena Lundström, Viveka Svensson, William Hogland, Kalmar, Växjö: Linnaeus university , 2018, p. 17-Conference paper (Refereed)
    Abstract [en]

    The heavy metal and metalloid contaminated groundwater is considered as one of the major global environmental disasters that need sustainable solutions. One sustainable environment-friendly solution is using plant-based remediation, or phytoremediation. For contaminated water aquatic plant based phytofiltration could be applied. A Swedish aquatic moss species (Warnstorfia fluitans) have been discovered to accumulate high levels of As (arsenic) from the water. In a number of areas in Sweden, the As content in the groundwater is high due to mining activities and geochemical conditions. Our hypothesis was that since this moss species could accumulate As from contaminated water it would be possible to apply in constructed wetland system for removal of As from water. The aim of this study was to investigate the removal of As from the outlet water by using W. fluitans in constructed mesocosm type wetland systems with various water flow speeds under greenhouse conditions. Besides these, As content in the vegetables (lettuce, Latuca sativa) grown in this outlet water was also analysed. The total As concentration was analysed with hydride generated atomic absorption spectrophotometry (HG-AAS). Results showed that W. fluitans could reduce the As concentration in the water with 36 and 56% from initial As concentration at high (5 mL/min) and low (1.5 mL/min) water flow rate, respectively. The As concentration in the vegetables was also lower when low flow outlet has been applied as irrigation water. In conclusion, the result fits our hypothesis that aquatic moss could be used in the constructed wetland system to reduce As content in irrigation water and by that also in the irrigated vegetables.

  • 6.
    Santos, Graziely Cristina
    et al.
    Univ Estadual Paulista, Brazil.
    Corso, Carlos Renato
    Univ Estadual Paulista, Brazil.
    Comparative Analysis of Azo Dye Biodegradation by Aspergillus oryzae and Phanerochaete chrysosporium2014In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 225, no 7, article id 2026Article in journal (Refereed)
    Abstract [en]

    The textile industry often releases effluents into the environment without proper treatment or complete dye removal. Azo dyes, which are characterized by azo groups (―N═N―), are frequently used in the textile industry. Among the different wastewater treatment methods available, biological treatment has been extensively studied. The aim of the present study was to compare the biodegradation of the azo dye Direct Blue 71 by the fungi Phanerochaete chrysosporium and Aspergillus oryzae in paramorphogenic form using a 100 μg/ml dye solution. Biodegradation tests were performed within 240 h. The absorbance values obtained with UV-VIS spectrophotometry were used to determine the absorbance ratio and the percentage of dye discoloration following the biodegradation test. FTIR analysis allowed the identification of molecular compounds in the solution before and after biodegradation. Both A. oryzae and P. chrysosporium demonstrated considerable potential regarding the biodegradation of dyes in wastewater. These results may contribute toward improving effluent treatment systems in the textile industry.

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