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Microbial Fuel cells, applications and biofilm characterizationKrige, Adolf January 2019 (has links)
Since the 1900’s it has been known that microorganisms are capable of generating electrical power through extracellular electron transfer by converting the energy found organic compounds (Potter, 1911). Microbial fuel cells (MFCs) has garnered more attention recently, and have shown promise in several applications, including wastewater treatment (Yakar et al., 2018), bioremediation (Rosenbaum & Franks, 2014), biosensors (ElMekawy et al., 2018) desalination (Zhang et al., 2018) and as an alternative renewable energy source in remote areas (Castro et al., 2014). In MFCs catalytic reactions of microorganisms oxidize an electron donor through extracellular electron transfer to the anode, under anaerobic conditions, with the cathode exposed to an electron acceptor, facilitating an electrical current (Zhuwei, Haoran & Tingyue, 2007; Lovley, 2006). For energy production in remote areas a low cost and easily accessible feed stock is required for the MFCs. Sweet sorghum is a drought tolerant feedstock with high biomass and sugar yields, good water-use efficiency, established production systems and the potential for genetic improvements. Because of these advantages sweet sorghum stalks were proposed as an attractive feedstock (Rooney et al., 2010; Matsakas & Christakopoulos, 2013). Dried sweet sorghum stalks were, therefore, tested as a raw material for power generation in a MFC, with anaerobic sludge from a biogas plant as inoculum (Sjöblom et al., 2017a). Using sorghum stalks the maximum voltage obtained was 546±10 mV, the maximum power and current density of 131±8 mW/m2 and 543±29 mA/m2 respectively and the coulombic efficiency was 2.2±0.5%. The Ohmic resistances were dominant, at an internal resistance of 182±17 Ω, calculated from polarization data. Furthermore, hydrolysis of the dried sorghum stalks did not improve the performance of the MFC but slightly increased the total energy per gram of substrate. During the MFC operation, the sugars were quickly fermented to formate, acetate, butyrate, lactate and propionate with acetate and butyrate being the key acids during electricity generation. Efficient electron transfer between the microorganisms and the electrodes is an essential aspect of bio-electrochemical systems such as microbial fuel cells. In order to design more efficient reactors and to modify microorganisms, for enhanced electricity production, understanding the mechanisms and dynamics of the electron transport chain is important. It has been found that outer membrane C-type cytochromes (OMCs) (including omcS and omcZ discussed in this study) play a key role in the electron transport chain of Geobacter sulfurreducens, a well-known, biofilm forming, electro-active microorganism (Millo et al., 2011; Lovley, 2008). It was found that Raman microscopy is capable of providing biochemical information, i.e., the redox state of c-type cytochromes (cyt-C) without damaging the microbial biofilm, allowing for in-situ observation. Raman microscopy was used to observe the oxidation state of OMCs in a suspended culture, as well as in a biofilm of an MFC. First, the oxidation state of the OMCs of suspended cultures from three G. sulfurreducens strains (PCA, KN400 and ΔpilA) was analyzed. It was found that the oxidation state can also be used as an indicator of the metabolic state of the cells, and it was confirmed that PilA, a structural pilin protein essential for long range electron transfer, is not required for external electron transfer. Furthermore, we designed a continuous, anaerobic MFC enabling in-situ Raman measurements of G. sulfurreducens biofilms during electricity generation, while poised using a potentiostat, in order to monitor and characterize the biofilm. Two strains were used, a wild strain, PCA, and a mutant, ΔOmcS. The cytochrome redox state, observed through the Raman spectra, could be altered by applying different poise voltages to the electrodes. This change was indirectly proportional to the modulation of current transferred from the cytochromes to the electrode. This change in Raman peak area was reproducible and reversible, indicating that the system could be used, in-situ, to analyze the oxidation state of proteins responsible for the electron transfer process and the kinetics thereof.
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Svensk matkonsumtion och dess påverkan på ekosystemtjänster : Hur svenskens påverkan på ekosystemtjänster genom matkonsumtion förändrats sedan 1960-talet / Swedish food consumption and its impact on ecosystem services : How the impact on ecosystem services from Swedish food consumption has changed since the 1960sBerglund, Ella, Gavefalk, Filip, Linderstam, Jakob, Malm, Arvid, Sjöbäck, Sandra January 2019 (has links)
Due to an increasing global population and changes in diets the impact of food consumption on the world’s ecosystems and their services has become more significant. The purpose of this project has been to investigate how the impact on ecosystem services from Swedish food consumption has changed over time and if this development is sustainable or not. A quantitative assessment of six different environmental impact factors has been carried out for each food category. The project clarifies how Swedish food consumption has developed since the 1960s, the origin of the food that has been consumed, which processes that affect the environment as well as the consequences from these impacts. The result showed that Swedish food consumption has increased considering quantity, that the consumption pattern has changed, and that the import of goods has increased since the 1960s. The average Swede eats more animal-based products such as meat, cheese and cream, along with more vegetable-based products such as fruit and berries, and vegetables. Instead, products such as milk and soured based products has decreased, while products made from flour and grains has stayed unchanged. The project shows that animal-based products, especially from ruminant animals, has a significantly higher ecological footprint in comparison with vegetable-based products, concerning most of the categories mentioned above. Considering that the swedes eat more animal-based products today than in the 1960sthefollowing conclusion, that the Swedish impact on ecosystem services has increased since the 1960s even though food production has become more efficient, could be drawn.
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Machine learning-assisted image analysis and metabarcoding for monitoring of plankton in the seas surrounding Sweden / Maskininlärningsbaserad bildanalys och DNA-streckkodning för övervakning av plankton i svenska havsområdenGarefelt, Karin January 2023 (has links)
I miljöövervakningen av haven runt Sverige har manuell mikroskopi av plankton länge varit den huvudsakliga tekniken för att övervaka växtplanktonbestånden och algblomningar. Nya tekniker utvärderas, men det är inte känt hur resultaten från de nyare teknikerna relaterar till varandra. Två tekniker som utvärderas av SMHI, flödesmikroskopi och DNA-streckkodning, har inte tidigare jämförts i litteraturen. Båda teknikerna har dock jämförts med traditionell mikroskopi. I det här projektet har provserier för DNA-streckkodning och automatiserad mikroskopi med Imaging FlowCytobot (IFCB) samlats in parallellt under en expedition i Egentliga Östersjön, Öresund, Kattegatt och Skagerrak. En bildklassificerare konstruerades med ett konvolutionellt neuronnät, som användes för att klassificera bilderna som tagits med IFCB:n. Resultaten från IFCB:n jämfördes med dem från DNA-streckkodning av 18S rRNA-genen. Jämförelsen visade stark korrelation mellan klassificeringen av bilder och DNA-streckkodning för vissa kiselalger (R>0.8), men teknikernas resultat skilde sig också åt i många fall. Skillnaderna kan studeras för att hitta svagheter i de båda teknikerna och utveckla dem vidare. / In environmental monitoring of the seas around Sweden, manual counting with microscopy is used to monitor the plankton communities and algal blooms. New techniques are currently being evaluated, including imaging flow cytometry and DNA metabarcoding, but it is not known how results from the different techniques relate to one another. Previous work has not compared imaging flow cytometry with metabarcoding, although both methods have been compared to traditional microscopy. In this project, samples for DNA metabarcoding and imaging flow cytometry with the Imaging FlowCytobot (IFCB) have been collected in parallel in the Baltic Proper, Öresund, Kattegat, and Skagerrak. To be able to process the large number of images from cytometry, an image classification algorithm based on convolutional neural networks and transfer learning was developed, which was used to classify the images collected. The results were compared to those obtained with 18S rRNA metabarcoding of the protist community. This new approach of comparing imaging flow cytometry with metabarcoding resulted in a strong (R>0.8) correlation for some diatom taxa, but discrepancies between the technologies were also observed. The discrepancies can be further studied to identify weaknesses in both techniques and refine them further.
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Biokonvertering av Brödavfall till Svampfilmer för Textila Applikationer / Bioconversion of Bread Waste to Fungal Films for Textile ApplicationsSyed, Samira January 2023 (has links)
Bread waste represents a significant portion of global food waste, necessitating innovative approaches for its valorization. This research project explores the utilization of bread waste through fermentation with Aspergillus oryzae to produce fungal film which could be used for textile applications. While previous studies have examined various applications of food waste, this project specifically targets the textile industry, aiming to mitigate pollution associated with conventional textile manufacturing. The objective of this project was to investigate the feasibility of creating fungal films derived from bread waste. Additionally, to analyze the material's properties through assessments of tensile strength, microscopic analysis, and the identification of an appropriate methodology for this investigation. The biomass suspension was prepared using an ultrafine grinder, and a kitchen blender was subsequently employed to minimize the presence of remaining solids from the grinding process. Additionally, a range of strategies for film casting and wet laying were implemented and evaluated. Wet laying involved combining fungal biomass with tannin to mimic the characteristics of leather. On the other hand, casting utilized pre-treated biomass suspension to assess the formation and quality of the films. As the research progressed and different tannins were used to treat the biomass, a methodology was developed, and glycerol was introduced as a plasticizer. Furthermore, nanocellulose was later incorporated exclusively for the casting of the films to serve as a binder. The films that were produced gave interesting results are observed in casted sheets containing nanocellulose and glycerol-infused biomass (3% BM + 2% Cellulose + 0.13 g Glycerol), exhibiting exceptional tensile strength (35.1 ± 3.42 MPa) and elongation (16.7 ± 5.98%). Wet laid biomass sheets treated with Tara and glycerol display tensile strength (19.9 ± 3.55 MPa) and elongation (6.66 ± 3.02%). These findings signify the potential for developing fungal films from bread waste, necessitating further research to refine methodologies. Overall, this research project paves the way for future advancements in fungal films derived from bread waste. By investigating the use of Aspergillus oryzae and employing wet laying and casting techniques, the project establishes a foundation for sustainable textile production. The successful utilization of bread waste not only addresses the issue of food waste but also contributes to reducing pollution in the textile industry.
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Optimization of sterilization method for cultivation of filamentous fungi on lemon wasteConradsson, Oliver, Ljungberg, David January 2023 (has links)
Consumption of citrus fruits and citrus juice production creates wastes, which could be valorized by using it for cultivating fungi. Before cultivation, the medium needs to be sterilized though autoclavation. Larger volumes used when autoclaving requires longer heating cycles and therefore runs the risk of degrading the medium to a greater extent. This research examines the effects of the volume lemon waste medium used while sterilizing. The aim is to find the largest volume still providing good growth for the filamentous fungus used, Rhizopus Delemar. Lemon waste was provided by Herrljunga Musteri AB and was pre-treated at 45°C for 2h. The liquid was strained and autoclaved in different volumetric series ranging from 200 – 10 000 mL, that was then used in 200 mL shake flask cultivations. A scale up in two 3,5 L bubble column reactors was also performed from the 10 000 mL autoclaved medium, after not observing severe impacts on growth. Testing was done by weighing biomass and HPLC analysis of sugars. The yield of the biomass in the shake flasks ranged from 0,11 – 0,14 g/g sugars and the biomass concentration ranged between 2,4 - 3,0 g/L. Overall, the volume of autoclavation seems to not too be of great concern when cultivating R. Delemar on lemon waste medium in the analyzed ranges.
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Effect of substrate types on fermentation of mixed cultures to produce volatile fatty acids / Effekt av substrattyper för fermentering av blandade kulturer för att producera flyktiga fettsyrorSehgal, Jayant January 2022 (has links)
Innovativa teknologier, produkter och processer krävs på grund av marknadens ökande behov av bioprodukter med låga koldioxidavtryck. Idén att producera flyktiga fettsyror via biologiska processer, främst genom anaerob fermentering med blandkulturer, har återupplivats på grund av den omfattande exploateringen av oljeresurser. Målet för denna studie var att utvärdera kvaliteten och livskraften för produktion av flyktiga fettsyror från enkla substrat. Flyktiga fettsyror-generering undersöktes i ett satsvis syrafermenteringssystem för tre enkla substrat (olja, stärkelse, och gelatin). Vi visade att ett initialt surt pH var fördelaktigt för acidogenes och den totala genereringen av flyktiga fettsyror för alla tre substraten. Den högsta produktionseffektiviteten av flyktiga fettsyror uppnåddes och flyktiga fettsyror genomgick evolutionär utveckling med blandad kulturfermentering som kördes vid ett initialt surt pH på 5,0. 7933,08 mg COD/L smörsyra producerades från stärkelse vid pH 3,87 på dag 15, vilket var den högsta nivån. Smörsyra och ättiksyra var de dominerande produkterna i det initiala sura pH-värdet 5. Alla tre substraten i batch-reaktorer visade högt produktionsutbyte av ättiksyra och smörsyra. Vid lågt initialt pH var propionsyra den vanligaste syratypen i olja. / Innovative technology, products, and processes are required because of the market's rising need for bioproducts with low carbon footprints. The concept of producing volatile fatty acids (VFAs) via biological processes, primarily through anaerobic mixed culture fermentation, has been revived because of the extensive exploitation of oil resources. The goal of this study was to evaluate the quantity and efficiency of VFA production from simple substrates. The generation of VFA was examined using a batch type acid fermentation system for three simple substrates (oil, starch, and gelatin). We showed that an initial acidic pH was advantageous for acidogenesis and the total generation of VFAs for all three substrates. The VFA production efficiency was achieved and underwent evolutionary development with mixed culture fermentation (MCF) tests running at an initial acidic pH of 5.0. 7933.08 mgCOD/L butyric acid were produced from starch at pH 3.87 at day 15, which was the highest level. Butyric and acetic acids were the predominant products in the initial acidic pH 5. All the three substrates in reactors showed high VFA production yield of acetic acid and butyric acid. At low initial pH, propionic acid was the most prevalent acid type in oil.
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Värdeskapande av koldioxid frånbiogasproduktion : En kartläggning över lämpliga CCU-tekniker för implementeringpå biogasanläggningar i Sverige / Value creation of carbon dioxide from biogas production : A survey of suitable CCU techniques for implementation at biogasplants in SwedenBroman, Nils January 2020 (has links)
Carbon dioxide from biogas production is currently considered to be without value and isbecause of this released into the atmosphere in the biogas upgrading process. The residualgas is a potential carbon source and can create value in the biogas manufacturing process.By finding a suitable value-creating process that utilizes carbon dioxide, it can be possibleto provide both economic and environmental incentives for companies to develop theiroperations. This project explored the possibility to create value from this CO2. Through anevaluation of the technical maturity of CCU technologies, a recommendation could be givenat the end of the project. An analysis of technical barriers, such as pollutants in the gas, aswell as barriers in the form of competence and corporate culture were examined in orderto provide a reasoned recommendation. The project mapped which value-creating systemswould be suitable for biogas producers in a Swedish context. This included established methaneand carbon dioxide upgrading techniques currently in use and suitable CCU techniquesthat can interact with the selected upgrading processes and serve as value creators. Based onthis survey, it was then possible to identify common, critical variables for these systems. Thereafter,a recommendation of an appropriate CCU technology could be given depending onthe CO2 composition produced. One conclusion from the study was that carbon dioxide concentrationsfrom the residual gas was often high (approx. 97-98 %) and did not contain anycorrosive or toxic components, and that this largely depends on how the digestion reactor ishandled in the production process. Thus, questions were raised about what the actual limitationsof the CCU are, as they did not seem to be technical. CCU techniques that proved to beof particular interest were pH regulation of sewage plants, CO2 as a nutrient substrate for thecultivation of microalgae, and manufacturing of dry-ice for refrigerated transports. All of thesetechnologies currently have a sufficiently high degree of technical maturity to be installedalready today. Other CCU techniques, such as "’Power to gas”, require a high CO2 concentrationand were discarded as the literature review did not suggest the economic potential forthem as they require additional CO2 upgrading steps. Instead, CCU techniques were chosenthat could be implemented directly with the existing CO2 quality. Furthermore, it was concludedthat one reason why CCU technologies have not been widely implemented is internalbarriers between distributors and manufacturers (or users) of CCU technologies. Thus, theuse of carbon dioxide from biogas production and implementation of CCU technologies canbe promoted by eliminating barriers in companies, such as a lack of both knowledge andfinancial incentives. / Koldioxid från biogasproduktion betraktas i dagsläget som utan värde och släpps ut i atmosfärenvid uppgradering av biogas. Restgasen är en potentiell kolkälla och kan vara värdeskapandeför biogasprocessen. Genom att finna en lämplig värdeskapande process som utnyttjarkoldioxid går det att ge både ekonomiska och miljömässiga incitament till företag att utvecklasin verksamhet. I detta projekt undersöktes möjligheten att skapa värde av denna CO2.Genom en utvärdering av den tekniska mognadsgraden hos CCU-tekniker kunde en rekommendationges vid projektets slut. En analys av tekniska hinder, såsom föroreningar i gassammansättningen,såväl som hinder i form av kompetens och företagskultur undersöktes för attkunna ge en motiverad rekommendation. I projektet kartlades vilka värdeskapande systemsom skulle passa för biogasproducenter i en svensk kontext. Detta inkluderade etableradeuppgraderingstekniker för metan- och koldioxid som används i dagsläget. I projektet undersöktesäven lämpliga CCU-tekniker som kan samverka med de valda uppgraderingsprocessernaoch och agera värdeskapande. Utifrån denna kartläggning kunde det sedan anges vilkagemensamma, kritiska variabler som finns för dessa system. Därefter kunde en rekommendationav lämplig CCU-teknik ges beroende på den producerade CO2 sammansättningen. Enslutsats i projektet var att koldioxid från restgasen ofta var av hög koncentration (ca. 97-98 %)och ej innehöll några korrosiva eller toxiska komponenter, och att detta till stor del beror påhur rötkammaren är hanterad i produktionsprocessen. Således väcktes frågor kring vilka defaktiska begränsningarna för CCU är, då de inte torde vara tekniska. CCU-tekniker som visadesig vara av särskilt intresse var pH-reglering av avloppsverk, CO2 som näringssubstratför odling av mikroalger, samt tillverkning av kolsyreis för kyltransporter. Samtliga dessatekniker har tillräckligt hög teknisk mognadsgrad för att kunna installeras i dagsläget. AndraCCU-tekniker, såsom ”Power to gas”, kräver en hög CO2-koncentration och avfärdades dålitteraturstudien inte talade för den ekonomiska potentialen i dessa eftersom de kräver ytterligareuppgraderingssteg för CO2. Således valdes istället CCU-tekniker som skulle gå attimplementera direkt med den befintliga CO2 kvalitén. Vidare drogs slutsatsen att en anledningtill att CCU-tekniker inte har blivit vida implementerade till stor del är interna hindermellan distributörer och tillverkare (eller utnyttjare) av CCU-tekniker. Således kan användandetav koldioxid från biogasproduktion och implementering av CCU-tekniker främjasgenom att eliminera hinder hos företag. I projektet yttrade sig detta som bristande ekonomiskaincitament och okunskap. Ett ökat användande av CCU-tekniker kan också uppnås genomatt införa lagar och regler som begränsar användandet av föråldrade tekniker som drivs avfossila bränslen, och som kan ersättas av klimatvänliga CCU-tekniker.
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Reptilförekomster och kopplingar till miljöfaktorer på Billingen : Inventering av reptilfauna med artificial cover objects på lokal nivå i Västsverige / Reptile occurences and connections to environmental factors on Billingen : Survey of reptile fauna with artificial cover objects on a local scale in Western SwedenCarlquist Segell, Maja January 2021 (has links)
Förlust av biologisk mångfald är den planetära gräns som överskrids mest, och medför bland de största hoten mot biosfärens integritet. Reptiler är funktionella delar i ekosystem, men habitatförlust, förändrad markanvändning och klimatförändringar orsakar globala populationsminskningar. Ekologisk övervakning möjliggör förståelse för arters tillstånd, och utveckling av bevarandeåtgärder. Denna förekomststudie syftar till att undersöka lokal reptilfauna, som inventerades med artificial cover objects (ACO) i två naturområden på Billingen, ett av de västsvenska platåbergen, i Skövde kommun 2021. Data från miljöbeskrivning och inventering samt över väderförhållanden samlades in, och samband mellan observationer och miljöfaktorer testades med statistiskt t-test för positiva skillnader mellan datagrupper. Skogsödla (Zootoca vivipara), kopparödla (Anguis fragilis), snok (Natrix natrix) och huggorm (Vipera berus),alla allmänna reptilarter i regionen, observerades i undersökningsområdet. Nio observationer gjordes under 20 regnfria dagar i juni och juli, med temperaturer över 18°C. Biotopkvaliteterna brynmiljöer och nektarresurser, solexponering och de öppna biotoperna beteshage och elledningsgata, förekom i signifikant högre utsträckning där observationer gjordes, än på platser utan observationer. Markfuktighet, mänsklig närvaro, naturvärden och områdesskydd uppvisade ingen signifikans. Resultaten överensstämmer med andra studier om reptilarternas habitat, och kan ses gälla på lokal nivå trots ett relativt litet dataunderlag. Effektiva reptilbevarande åtgärder i närområdet kan innebära upprätthållande och skapande av ytor med hög solinstrålning och strukturell komplexitet, fortsatt men inte utökat lågintensivt naturbete, samt ökad halt avträdslagsblandning och brynmiljöer i produktionsskog. Kunskapen kring reptilers ekologi, samtövervakningen av populationer, behöver utökas. Det rekommenderas vidare studier om reptiler, deras habitat och bevarande av biologisk mångfald på lokala nivåer. / Biodiversity loss is the most exceeded planetary boundary, and entails some of the largest threats against biosphere integrity. Reptiles are functional parts of ecosystems, but habitat loss and changes in land use and climate are causing global population declines. Ecological monitoring enables understanding of species’ conditions, and development of conservation measures. This occurrence study aims to investigate local reptile fauna, surveyed using artificial cover objects (ACOs), in two areas on Billingen, one of Western Sweden’s table mountains, in Skövde municipality 2021. Environmental, survey and weather data were collected, and relations between observations and environmental factors were tested with statistical t-test for positive differences between data groups. Zootoca vivipara, Anguis fragilis, Natrix natrix and Vipera berus, all regionally common reptile species, were observed in the investigated area. Nine observationswere made during 20 rain-free days in June and July, with temperatures above 18°C. Solarexposure, biotope qualities Forest edges and Nectar resources, and the open biotopes Pasture and Powerline corridor, occurred in significantly higher extent where observations were made, than on sites without observations. Soil moisture, Human presence, Natural values and Environmental protection did not exhibit any significance. The results correspond to other studies on the reptilespecies’ habitat, and may apply on a local scale despite a relatively small data amount. Effective conservation measures for local reptiles can imply maintaining and creating spaces with high solar radiation and structural complexity, continued but not extended low-intensity grazing, and increasing tree species mixture and edge zones in production forests. Knowledge on reptile ecology and population monitoring needs to increase. Further studies on reptiles and biodiversity conservation on local scales are recommended.
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