| 1. |
- Acevedo, F., et al.
(författare)
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A practical culture technique for enhanced production of manganese peroxidase by Anthracophyllum discolor Sp4
- 2011
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Ingår i: Brazilian archives of biology and technology. - 1516-8913 .- 1678-4324. ; 54:6, s. 1175-1186
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Tidskriftsartikel (refereegranskat)abstract
- In this study, different growth conditions of Anthracophyllum discolor Sp4 including the effect of agitation, additions of lignocellulosic support, inducer and surfactant were evaluated on the MnP production in Kirk medium using a culture system made up of the tubes containing the glass bead. The highest MnP production (1,354 U/L on day 13) was obtained when the medium was supplemented with wheat grain and 0.25 mM MnSO 4 as inducer, under static conditions at 30°C. Two isoenzymes were purified (35 and 38 kDa respectively). MnP presented a maximal activity in the pH range between 4.5 and 5.5, a relatively high temperature tolerance (50°C) and a high catalytic activity for 2,6-dimethoxyphenol and hydrogen peroxide.
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| 2. |
- Acevedo, F., et al.
(författare)
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Degradation of polycyclic aromatic hydrocarbons by free and nanoclay-immobilized manganese peroxidase from Anthracophyllum discolor
- 2010
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 80:3, s. 271-278
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Tidskriftsartikel (refereegranskat)abstract
- Manganese peroxidase (MnP) produced by Anthracophyllum discolor, a Chilean white rot fungus, was immobilized on nanoclay obtained from volcanic soil and its ability to degrade polycyclic aromatic hydrocarbons (PAHs) compared with the free enzyme was evaluated. At the same time, nanoclay characterization was performed.Nanoclay characterization by transmission electronic microscopy showed a particle average size smaller than 100nm. The isoelectric points (IEP) of nanoclay and MnP from A. discolor were 7.0 and 3.7, respectively, as determined by micro electrophoresis migration and preparative isoelectric focusing. Results indicated that 75% of the enzyme was immobilized on the nanoclay through physical adsorption. As compared to the free enzyme, immobilized MnP from A. discolor achieved an improved stability to temperature and pH. The activation energy (Ea) value for immobilized MnP (51.9kJmol -1) was higher than that of the free MnP (34.4kJmol -1).The immobilized enzyme was able to degrade pyrene (>86%), anthracene (>65%), alone or in mixture, and to a less extent fluoranthene (<15.2%) and phenanthrene (<8.6%). Compared to free MnP from A. discolor, the enzyme immobilized on nanoclay enhanced the enzymatic transformation of anthracene in soil.Overall results indicate that nanoclay, a carrier of natural origin, is a suitable support material for MnP immobilization. In addition, immobilized MnP shows an increased stability to high temperature, pH and time storage, as well as an enhanced PAHs degradation efficiency in soil. All these characteristics may suggest the possible use of nanoclay-immobilized MnP from A. discolor as a valuable option for in situ bioremediation purposes. © 2010 Elsevier Ltd.
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| 3. |
- Acevedo, F., et al.
(författare)
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Degradation of polycyclic aromatic hydrocarbons by the Chilean white-rot fungus Anthracophyllum discolor
- 2011
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 185:1, s. 212-219
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Tidskriftsartikel (refereegranskat)abstract
- The degradation of three- and four-ring polycyclic aromatic hydrocarbons (PAHs) in Kirk medium by Anthracophyllum discolor, a white-rot fungus isolated from the forest of southern Chile, was evaluated. In addition, the removal efficiency of three-, four- and five-ring PAHs in contaminated soil bioaugmented with A. discolor in the absence and presence of indigenous soil microorganisms was investigated. Production of lignin-degrading enzymes and PAH mineralization in the soil were also determined. A. discolor was able to degrade PAHs in Kirk medium with the highest removal occurring in a PAH mixture, suggesting synergistic effects between PAHs or possible cometabolism. A high removal capability for phenanthrene (62%), anthracene (73%), fluoranthene (54%), pyrene (60%) and benzo(a)pyrene (75%) was observed in autoclaved soil inoculated with A. discolor in the absence of indigenous microorganisms, associated with the production of manganese peroxidase (MnP). The metabolites found in the PAH degradation were anthraquinone, phthalic acid, 4-hydroxy-9-fluorenone, 9-fluorenone and 4,5-dihydropyrene. A. discolor was able to mineralize 9% of the phenanthrene. In non-autoclaved soil, the inoculation with A. discolor did not improve the removal efficiency of PAHs. Suitable conditions must be found to promote a successful fungal bioaugmentation in non-autoclaved soils. © 2010 Elsevier B.V.
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| 4. |
- Ahlberg-Eliasson, Karin, et al.
(författare)
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Production efficiency of Swedish farm-scale biogas plants
- 2017
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 97, s. 27-37
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Tidskriftsartikel (refereegranskat)abstract
- Biogas from agricultural waste streams represents an important way to produce fossil-free energy, allow nutrient recycling and reduce greenhouse gas emissions. However, biogas production from agricultural substrates is currently far from reaching its full potential. In Sweden, the number of biogas plants and their output have increased in recent years, but they are still experiencing harsh economic conditions. A recent evaluation (2010–2015) of 31 farm-scale biogas production facilities in Sweden sought to identify parameters of importance for further positive development. In this paper, data on plant operation, gas yield and digestate quality for 27 of these plants are summarised and statistically analysed to investigate factors that could allow an increase in overall biogas production and in nutrient content in the digestate. The analysis showed that addition of co-substrates to manure results in higher gas production, expressed as both specific methane potential and volumetric gas production, than when manure is the sole substrate. Use of co-substrate was also found to be influential for the nutrient content of the digestate. These observed improvements caused by co-digestion should be considered when subsidy systems for manure-based biogas processes are being created, as they could also improve the economics of biogas production. However, to achieve higher efficiency in existing biogas plants and to improve the situation for future investments, a more detailed, long-term evaluation programme should also be considered.
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| 5. |
- Ahlgren, Serina, et al.
(författare)
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Climate and biodiversity impact of beef and lamb production – A case study in Sweden
- 2024
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Ingår i: Agricultural Systems. - : Elsevier Ltd. - 1873-2267 .- 0308-521X. ; 219
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: The climate impact of meat production is a hotly debated topic. What is less often highlighted is that grazing ruminants can have positive impacts on biodiversity. OBJECTIVE: The aim of this study was to use a life cycle perspective to assess both the climate and biodiversity impact of different beef and lamb production systems in Sweden. METHODS: Applying a life cycle perspective, a quantitative method to assess biodiversity was used, with a scoring system based on land use. For the climate impact calculations, the ClimAg biophysical systems model was used, including emissions from drained organic soils and carbon sequestration in mineral soils. The functional unit was 1 kg carcass weight. RESULTS AND CONCLUSIONS: The results indicated large differences in biodiversity and climate impact between the production systems studied. Dairy bulls had relative low emissions of greenhouse gases, but also a low biodiversity score (a high score indicates higher level of biodiversity). Beef breed steers and heifers had higher emissions of greenhouse gases but a higher biodiversity score, suggesting a trade-off between climate and biodiversity impact. Also for lamb meat, greenhouse gas emissions vary among production systems. A system with winter born lambs slaughtered in spring, closely followed by spring born lambs slaughtered in autumn, had the lowest emissions, while spring born lambs slaughtered in winter had the highest emissions. Winter lambs on the other hand, had a relatively high biodiversity score, due to a long rearing period and an extensive land use with a high proportion of semi-natural grasslands. Climate impact was in all systems related to methane from enteric fermentation, emissions from manure storage, and emissions from organic soils. With the assumptions made in this study, soil carbon sequestration is suggested to reduce the climate impact by 5–7% of the total emissions. Biodiversity impact was in all systems positively related to the amount of grazing in permanent grasslands, in particular semi-natural grasslands. Because semi-natural grasslands are among the most species rich terrestrial ecosystems in Europe, a large surface area grazed resulted in high biodiversity scores in the present model. SIGNIFICANCE: This study used a novel approach for biodiversity assessment, where the positive contribution of semi-natural grasslands to biodiversity was quantified and put in relation to the modelled climate impact.
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| 6. |
- Ahlgren, Serina, et al.
(författare)
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Miljöpåverkan av svensk nöt- och lammköttsproduktion
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med denna studie har varit att beräkna miljöpåverkan från olika svenska uppfödningsmodeller för nöt- och lammkött i produktionsområdena Götalands norra slättbygder, Götalands skogsbygder, Nedre Norrland samt del av Götalands mellanbygd (Gotland). Inom nötköttsproduktion har mjölkrastjur, mjölkrasstut, köttrastjur, köttrasstut och köttraskviga studerats. För lammkött har vårlamm, höstlamm och vinterlamm undersökts. Miljöpåverkanskategorier som ingått i studien är klimatpåverkan, markanvändning, kväveutsläpp samt påverkan på biologisk mångfald.
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| 7. |
- Ahlgren, Serina, et al.
(författare)
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Review of methodological choices in LCA of biorefinery systems - key issues and recommendations
- 2015
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Ingår i: Biofuels, Bioproducts and Biorefining. - : Wiley. - 1932-1031 .- 1932-104X. ; 9:5, s. 606-619
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Forskningsöversikt (refereegranskat)abstract
- The current trend in biomass conversion technologies is toward more efficient utilization of biomass feedstock in multiproduct biorefineries. Many life-cycle assessment (LCA) studies of biorefinery systems have been performed but differ in how they use the LCA methodology. Based on a review of existing LCA standards and guidelines, this paper provides recommendations on how to handle key methodological issues when performing LCA studies of biorefinery systems. Six key issues were identified: (i) goal definition, (ii) functional unit, (iii) allocation of biorefinery outputs, (iv) allocation of biomass feedstock, (v) land use, and (vi) biogenic carbon and timing of emissions. Many of the standards and guidelines reviewed here provide only general methodological recommendations. Some make more specific methodological recommendations, but these often differ between standards. In this paper we present some clarifications (e.g. examples of research questions and suitable functional units) and methodological recommendations (e.g. on allocation).
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| 8. |
- Ahlgren, Serina, et al.
(författare)
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Tractive power in organic farming based on fuel cell technology : Energy balance and environmental load
- 2009
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Ingår i: Agricultural Systems. - : Elsevier BV. - 0308-521X .- 1873-2267. ; 102:1-3, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- This study analysed a future hypothetical organic farm self-sufficient in renewable tractor fuel. Biomass from the farm was assumed to be transported to a central fuel production plant and the fuel returned to the farm, where it was utilised in fuel cell powered tractors. The land use, energy balance and environmental impact of five different scenarios were studied. In the first two scenarios, straw was used as raw material for production of hydrogen or methanol via thermochemical gasification. In the third and fourth scenarios, short rotation forest (Salix) was used as raw material for the same fuels. In the fifth scenario, ley was used as raw material for hydrogen fuel via biogas production. The straw scenarios had the lowest impact in all studied environmental impact categories since the Salix scenarios had higher soil emissions and the ley scenario had comparatively large emissions from the fuel production. The energy balance was also favourable for straw, 16.3 and 19.5 for hydrogen and methanol respectively, compared to Salix 14.2 and 15.6. For ley to hydrogen the energy balance was only 6.1 due to low efficiency in the fuel production. In the Salix scenarios, 1.6% and 2.0% of the land was set aside for raw material production in the hydrogen and methanol scenarios respectively. In the straw scenarios no land needed to be reserved, but straw was collected on 4.3% and 5.3% of the area for hydrogen and methanol respectively. To produce hydrogen from ley, 4% of the land was harvested. The study showed that the difference in environmental performance lay in choice of raw material rather than choice of fuel. Hydrogen is a gas with low volumetric energy density, which requires an adapted infrastructure and tractors equipped with gas tanks. This leads to the conclusion that methanol probably will be the preferred choice if a fuel cell powered farm would be put into practice in the future. © 2009 Elsevier Ltd. All rights reserved.
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| 9. |
- Ahlgren, Serina, et al.
(författare)
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Växtnäring till jordbruket i osäkra tider – scenarier och dokumentation från en workshop
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Mineralgödsel är en förutsättning för dagens konventionella jordbruk och utan mineralgödsel blir det problematiskt att få fram tillräckligt med foder och livsmedel. Sverige har ingen egen produktion av mineralgödsel och försörjningen är därför helt beroende av import. Denna rapport beskriver hur växtnäring hanteras ur beredskapssynpunkt i Sverige idag, och ger också en liten inblick i hur växtnäring har hanterats i tidigare kriser och pristoppar i andra länder. Rapporten beskriver också tre olika tänkbara krisscenarier där växtnäring behöver hanteras på olika sätt för att säkerställa livsmedelsförsörjningen i Sverige. Tidsperspektivet i scenarierna är relativt kort: ett fokuserar på hur växtnäringsförsörjningen kan lösas under den kommande växtodlingssäsongen medan de andra två scenarierna fokuserar på några år framåt i tiden. Scenarierna diskuterades på en workshop med deltagare från jordbruks- och växtnäringssektorn. I rapporten redovisas diskussionerna från workshopen. Under workshopen lyftes några brister i dagens system och förslag på vilket stöd och långsiktiga förändringar som behövs, för att säkra tillgången på växtnäring i Sverige under en kris: • I vardagen finns det ingen nationell eller regional planering av den svenska primärproduktionen och fördelningen av mineralgödsel eller andra insatsvaror till olika verksamheter, utan allt sköts av marknaden. Det finns därför ingen ansvarig offentlig aktör som har helhetsansvar för området. Vid en allvarlig brist på mineralgödsel kan det behövas någon som kliver in, säkrar leveranser och tar beslut om prioriteringar till olika verksamheter och eventuellt styrning av vem som odlar vad. Det kan även behövas någon som ansvarar för förebyggande arbete. • En trygg och resilient försörjning av växtnäring kommer att kräva en mångfald av lösningar. Dessa kräver i varierande grad samordning mellan marknadsaktörer och myndigheter. Vissa kan också kräva ny lagstiftning. Ett ”Gödselmedelskabinett” med ansvar att ta fram en strategi föreslogs. • Lagstiftning bör justeras alternativt införas för att utöka möjligheterna till miljö- och hälsomässigt säker återvinning av resurser från restflöden. Sådana ändringar skulle kunna förberedas redan nu, så att de snabbt kan träda i kraft i händelse av kris eller krig. • Sverige bör utveckla gemensamma strategier och avtal med andra länder, främst inom Norden, till exempel en nordisk strategi för växtnäringsfrågor.
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| 10. |
- Ahmadi Moghaddam, Elham, et al.
(författare)
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Energy balance and global warming potential of biogas-based fuels from a life cycle perspective
- 2015
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Ingår i: Fuel Processing Technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 132, s. 74-82
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Tidskriftsartikel (refereegranskat)abstract
- Biogas is a multifunctional energy carrier currently used for co-generation or compressed biomethane as vehicle fuel. Gas-to-liquid (GTL) technology enables conversion of biogas into other energy carriers with higher energy density, facilitating fuel distribution. The energy efficiency and global warming potential (GWP) for conversion of biogas to compressed biogas (CBG), liquefied biogas (LBG), Fischer–Tropsch diesel (FTD), methanol and dimethyl ether (DME) were studied in a life cycle perspective covering the technical system from raw biogas to use in city buses. CBG, methanol and DME showed the best specific fuel productivity. However, when fuel distribution distances were longer, DME, LBG and methanol showed the best energy balance. Methanol, FTD and DME emitted half the GWP of LBG and CBG. Choice of electricity mix had a large impact on GWP performance. Overall, taking into account the different impact categories, combustion properties and fuel yield from raw biogas, DME showed the best performance of the fuel conversion scenarios assessed.
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