Antibodies are a class of proteins that are made by the immune system to recognize harmful organisms and molecules. Their exceptional capability of specifically recognizing molecules has been investigated for over a century and information thereof has been utilized for a variety of applications including vaccine and generation of therapeutic antibodies. Occasionally, instead of protecting the host against pathogens, antibodies can recognize constituents of the host and thereby cause an autoimmune reaction that eventually can lead to a disease. Therefore, it is of great interest to understand what the antibodies bind to and their specificities.   The last decades of technical development and availability of protein and peptide microarrays have enabled large-scale profiling of antibodies and precise determination of their specificities through epitope mapping. In this thesis the aim was to use affinity proteomics tools to profile antibodies, determine their specificities, and discover potential associations of autoantigens to disease by analyzing blood-derived samples with microarray-based methods.   In Paper I, 57 serum samples from patients with the suggested autoimmune disease narcolepsy, were analyzed on planar antigen microarrays with 10,846 human protein fragments. Verification on an independent sample collection consisting of serum samples from 176 individuals, revealed METTL22 and NT5C1A as two potential autoantigens. In Paper II, antibodies from 53 plasma samples from patients with first-episode psychosis, a condition suggested to have a partial autoimmune component, were analyzed on planar antigen microarrays with 2,304 human protein fragments. After a follow-up study of the patients, antibodies toward an antigen representing the three proteins, PAGE2, PAGE2B, PAGE5, was found associated to an increased risk of developing schizophrenia. In Paper III, serum and plasma samples from patients with the autoimmune diseases multiple sclerosis and narcolepsy, were epitope mapped on high-density peptide microarrays with approximately 2.2 million peptides. Technical and biological verification, by using other microarray technology and analyzing  samples from 448 patients, revealed one peptide for multiple sclerosis and narcolepsy, representing the proteins MAP3K7 and NRXN1, with higher antibody reactivity towards in each group, respectively. In Paper IV, purified polyclonal antibodies raised against a surface antigen found on malaria-infected erythrocytes, were profiled on the peptide microarrays representing all proteins found on malaria-infected erythrocytes derived from Plasmodium falciparum. Then, different Plasmodium falciparum strains were analyzed by immunofluorescence microscopy and western blots, using the epitope mapped antibodies. The performance of the immunoassays were compared to the identified epitopes, and validated by RNA sequencing.   In conclusion, these investigations describe multiplex methods to identify and characterize antibodies, their disease association and epitopes. Follow-up studies are needed to determine their potential use and clinical value. / <p>QC 20170905</p>

The importance of sensing Nitric Oxide (NO) in physiology and medicine has led us to explore the reactivity of NO with organometallic Re dyes. Rhenium complexes were synthesized with the ability to react with NO and sense it under physiological conditions. Fluorescent 1,10-phenantroline complexes (phen)Re(PPh3)(CO)2OSO2CF3 (1) and (phen)Re(CH3CN)(CO)2OSO2CF3 (3) can sense NO in the range of 10 - 150 mM showing a decrease in fluorescence response at 514 nm and 532 nm respectively, upon NO-donor addition (lexc = 360 nm). (phen)Re(THF)(CO)2OSO2CF3 (2) showed a ratiometric response with a decrease in fluorescence intensity at 585 nm and an increase at 445 nm. These complexes were characterized by FT-IR, 1H-NMR, 13C-NMR, and 19F‑NMR. The quantum yields (F) and lifetimes (t) were also determined. On the basis of 19F‑NMR and 1H-NMR spectroscopic evidence, the proposed mechanism of action involves dissociation of CF3SO3- (abbreviated as OTf-) together with PPh3, (for 1), THF (for 2), or CH3CN (for 3). Fluorescence microscopy showed that 1 permeates through the cell membrane of rat aortic endothelial cells (RAOEC) and 2 gives increase in cell fluorescence response at 450 nm when exogenous NO is added to RAOEC. The Re complexes of dppz (dppz = 2,2’-dipyrido[3,2-a:2,3’-c]phenazine) (dppz)Re(THF)(CO)2OSO2CF3 (A2) and (dppz)Re(CH3CN)(CO)2OSO2CF3) (A3) were synthesized using the same methods as for complexes 1 and 3. Even though the dppz complexes exhibited similar behavior than the phenanthroline analogs, the signal changes were small and the results were inconclusive. The a-Diimine Re complexes of Xy-DAD (XyDAD = 1,4-bis-[2,6-dimethylphenyl]-1,4-diazo-1,3-butadiene) (Xy-DAD)Re(THF)(CO)2OSO2CF3 (8) and (Xy-DAD)Re(CH3CN)(CO)2OSO2CF3 (9) showed reactivity with NO and CN- with a response in the visible range of the absorption spectrum. These diazadiene (DAD) complexes showed decreased reactivity with NO and CN- in the presence of oxidants. The i-PrDAD complexes (i-PrDAD = 1,4‑bis-[2,6-diisopropylphenyl]-1,4-diazo-1,3-butadiene) (i‑Pr‑DAD)Re(THF)(CO)2OTf (10) and (i‑Pr‑DAD)Re(CH3CN)(CO)2OTf (11) exhibited similar behavior with the Xy-DAD analogs, but the spectral changes were much smaller and the results were inconclusive. The ESI-MS Mass Spectrometry studies of the phenanthroline complexes 1, and 2, after reaction with NO-donor showed that 1 and 2 react with NO to give [Re(CO)2(NO)2S2]+ species, while (phen)Re(CO)3Cl and (phen)Re(CO)3OSO2CF3 do not show any metal-NO containing products, which is consistent with the fluorescence studies.

Salmonella är en gramnegativ bakterie som tillhör gruppen Enterobacteriacea. Bakterien delas in i två arter S. enterica och S. bongori och totalt har mer än 2600 serotyper upptäckts. Dessa serotyper skiljs från varandra utifrån sina flagellära H-antigener och somatiska O-antigener. Salmonellos är ett exempel på ett sjukdomstillstånd som orsakas av olika salmonella typer. De flesta salmonellainfektioner hos människor sker genom konsumering av kontaminerade livsmedel med bakterien. Polymerase chain reaction, PCR, är en snabb metod som kan detektera bakterier i till exempel livsmedel. I metoden används omväxlande upphettning och nedkylning av PCR-proven. Reaktionen i PCR sker i ett antal steg som möjliggör bildning av många kopior av DNA efter bara 40 cykler. Syftet med denna studie var att validera PCR metoden genom att hitta olika koncentrationer av salmonella i 25 gram värmebehandlad kycklingprov. Metoden börjades med att inokulera kycklingproven med salmonella och de bestämda halterna var 100, 10 och 1 cfu/prov. Huvudfokus var att hitta 1 cfu/kycklingprov och för att uppnå målet gjordes därför totalt fyra försök för att kunna dra pålitliga resultat och slutsatser. Vid varje försök gjordes två metoder parallellt där den ena var PCR metoden medan den andra var referens till PCR och genomfördes bara genom odling på agarplattor. Positiva prover bekräftades genom konfirmering i ett antal steg och vid varje försök gjordes negativ kontroll för att undvika falsk positiva resultat. Resultatet visade att 100 cfu/prov och 10 cfu/prov i kycklingprov kunde detekteras med PCR. Det närmaste värdet till 1 cfu/prov som var målet, blev 0,8 cfu/prov och med denna bakteriehalt lyckades PCR detektera två positiva prover av totalt tre prover. Den låga bakteriehalten behöver därför upprepas flera gånger för att metoden ska kunna valideras.

<p>This research was conducted to develop and evaluate a screening tool for Hepatic Steatosis (or fatty liver) detection using machine learning based models. The developed models are intended to be used as a potential clinical decision support tool for identifying patients with Non-Alcoholic Fatty  Liver  Disease  (NAFLD).  Two  versions  of  a  HS  prediction  tool  are  discussed  in  Paper  1, Objectives 1A, and 1B, respectively.</p> <p>Explainability  analysis  of  the  developed  models  is  also  a  major  component  of  this  work, discussed in Paper 2. Models from Paper 1 are analyzed further for interpretability and the results are then compared with current clinical literature. Insights from the explainability analysis are used to  identify  best  models  that  follow  the  clinical  literature  logically.  Most  contributing  features within each model are also identified in this work.</p> <p>Another aspect of NAFLD management is related to the chronic exposure to heavy metals in the environment (such as: Arsenic, Lead, Cadmium etc.). The heavy metal exposure component is explored in two ways in this dissertation. In paper 3, another version of the ML-based screening tool is explored by including heavy metal exposure data. The results from the model (with heavy metal data) are then compared with models that exclude the heavy metal exposure data. The results and their implications are discussed in paper 3.</p> <p>Arsenic is a major hepatotoxin and the chronic exposure can lead to severe liver injury. In Paper  4,  a  commercially  available  Arsenic  detection  kit  was examined  for  Arsenic  detection  in water  at  a  household  level.  The  kit  was  evaluated  following  a  short  experimental  plan  and  the obtained  results  are  discussed.  Finally,  the  obtained  images  were  quantified  digitally  using  a customized image analysis and pattern recognition algorithm. The methods used for quantification and the obtained results are also discussed.</p> <p><br></p>

This study set out to express, purify and characterize twelve ammonia lyase enzymes for potential application as a supplement to a treatment of an inborn error of metabolism disease. The DNA sequence for two wild-type ammonia lyases, three modified ammonia lyases and seven resurrected ancestral ammonia lyases had been synthesized and cloned in vectors. These were transformed into Escherichia coli, expressed, purified using immobilized metal affinity chromatography and size exclusion chromatography and characterized. Ten of the enzymes were successfully expressed and purified. All enzymes had a higher turnover number with substrate 1 than with substrate 2. The wild-types showed the highest catalytic turnover and one of them displayed substrate cooperativity. The modified enzymes were inactive. Some ancestral enzymes were active and had decreasing kcat with age. A promising ancestral enzymes was found that showed a kcat of 2,85 s-1 with substrate 1 and 1,82 s-1 with substrate 2. The ancestral enzymes had a lower Km with substrate 2 compared to substrate 1, while one of the wild-types had a higher Km with substrate 2 than with substrate 1, indicating that the substrate affinity has switched. The ancestral enzymes had increased thermostability compared to the wild-types which increased with age. Ranging from a +7C increase in melting temperature with the youngest ancestral enzyme to +10,7C with the oldest tested enzyme, comparing with one of the wild-types. The promising ancestral enzyme displayed a higher stability than the wild-types during long term incubation in 37_C and 25_C, since it did not become prone to aggregation,it did not show visible degradation on SDS-PAGE and it retained the highest activity following incubation. It was also demonstrated that neither wild-types nor the promising ancestral enzyme were stable in a simulated gut environment. The promising ancestral enzyme and one of the wild-types degraded substrate 1 and 2 in serum. Using the resurrection of ancestral sequences a promising enzyme has been produced and characterized, displaying properties that are desired in therapeutic enzymes. The enzyme did not aggregate or become prone to aggregation over time, it was thermostable, it was active in serum and had acceptable catalytic properties. For therapeutic application of the ancestral enzyme, immunogenicty should be analyzed in silico and in vitro followed by further investigation in vivo. / Målet med denna studie var att uttrycka, rena och karaktärisera tolv ammonia lyase enzymer, för potentiell användning som komplement till en behandling utav en sjukdom, som tillhör sjukdomsgruppen medfödda ämnesomsättningsrubbningar. DNA sekvensen för två vild-typammonia lyaser, tre modifierade ammonia lyaser och sju återuppväckta ammonia lyaser hade blivit syntetiserade och klonade i vektorer. E.coli celler blev transformerade med vektorerna, vilka uttryckte enzymerna, som renades med hjälp av immobilized metal affinity chromatography och gelfiltrering och karaktäriserades. Tio utav enzymerna kunde uttryckas och renas. Alla enzymer hade högre katalytisk omsättning av substrat 1 än substrat 2. Vildtyperna hade högst kcat med båda substrat och en utav dem uppvisade substratsammarbete. De modifierade enzymerna var inaktiva. Några av de återuppväckta ammonia lyaserna var aktiva och kcat minskade med ålder. Ett av de återuppväckta enzymerna var lovande och hade ett kcat värde av 2,85 s-1 med substrat 1 och 1,82 s-1 med substrat 2. De återuppväckta enzymerna hade ett lägre Km värde för substrat 2 än substrat 1, jämfört med en utav vildtyperna som hade ett högre Km värde för substrat 2 än substrat 1, vilket indikerar ett skifte i substrataffinitet. De återuppväckta enzymerna var mer termostabilia än vild-typerna och termostabiliteten ökar med ålder. Ökningen i smälttemperatur låg i spannet av +7C för de yngsta återuppväckta enzymerna till + 10,7C för det äldsta testade återuppväckta enzymet, vid jämförelse med en utav vild-typerna. Det lovande återuppväckta enzymet demonstrerade även en högre stabilitet än vild-typerna under långtidsinkubering, eftersom den inte blev benägen att aggregera, den uppvisade ingen nedbrytning på SDS-PAGE och den behöll högst aktivitet efter inkubering. Det bevisades även att varken vild-typerna eller det lovande återuppväckta enzymet var stabila i en simulerad magsäcksmiljö. Både det lovande återuppväckta enzymet och en av vild-typerna bröt ner substrat 1 och 2 i serum. Genom att återuppväcka sekvenser kunde ett lovande enzym produceras och karaktäriseras, vilket uppvisade egenskaper som är eftertraktade i terapeutiska enzymer. Enzymet aggregerade ej, det blev inte benäget att aggregera över tid, det var termostabilt, det var aktivt i serum och hade acceptabla katalytiska egenskaper. För terapeutisk applikation av det återuppväckta enzymet, borde analys av dess immunogenicitet utföras in silico och in vitro följt av vidare undersökning in vivo.

Bacteria typically adhere to various cell surfaces present in the human body to colonise or invade human tissues. Staphylococcus aureus (S. aureus) can express the fibronectin-binding proteins A and B (FnBP-A, FnBP-B) that can facilitate the binding of multiple copies of fibronectin (Fn). In addition, Fn bound to the bacterium trigger activation of α5β1 integrins found on the cells and facilitate invasion of human cells. Although the invasion mechanisms regarding signalling pathways and overall host cell interactions have been defined, the quantitative relationship between the mediators of invasion and the temporal kinetics has not yet been elucidated. In this thesis, newly developed microscopy-based methods have been used to quantify the interactions between H1299 cells and S. aureus at various Fn concentrations. After an approximate Fn concentration of 15 μg/ml, the S. aureus bacteria strains become saturated both for the wildtype and the negative control strains. Additionally, using the step-by-step protocol developed during this study, adhesion of the wildtype strain of S. aureus with 15 μg/ml Fn is occurring on the H1299 cells. Although adjustments to the protocol are needed, this adhesion mechanism will lead to an internalisation of the S. aureus strains to the H1299 cells.

<p>Non-invasive electromagnetic brain stimulation uses electrodes and/or coils to modulate brain activity via the induced E-fields. E-field dosimetry solvers have improved non-invasive electromagnetic brain stimulation protocol and our understanding of neuroscience. However, E-field dosimetry techniques are incomplete in that the contributions of non-linear neuron activity are left unaccounted for. To better understand the neurological effects of non-invasive electromagnetic stimulation, we introduce an integral equation formulation for modeling the non-linear behavior of neurons due to an incident E-field generated by electrode and coil sources. We formulate the new integral equation using a boundary element approach. We compare the boundary element solver accuracy with an established finite element solver and multi-scale cable equation approaches. Unlike previous approaches, this new boundary integral formulation avoids multi-scaling challenges from meshing while retaining the accuracy and the robust spatial support of integral equation-based methods. The memory savings from switching to surface meshes makes simulations with more complex morphologies computationally tractable. Additionally, we examine the ability of neurons to couple to one another via the local extracellular fields. Examples of simulations with both transcranial electric and magnetic stimulation results for simple geometries are used to illustrate the capabilities of a boundary integral approach. This boundary integral method will aid the development of better neurological understanding, delineate the mechanisms by which electromagnetic stimulation engenders neuronal activity, and aid in modeling local E-field coupling.</p>

This project aimed at exploring new hybrid materials to be used for acoustophoresis applications. Acoustophoresis can be used to manipulate particles inside a microfluidic channel by creating ultrasound standing waves within the channel [1]. This can be used for cell separation [2] or trapping of particles [3]. The intent of this project was to create materials for use in microfluidic channels that would be cheaper and easier to manufacture than those traditionally used, while still having adequate acoustic properties to allow for use in acoustopheresis. This was done by investigating whether the addition of glass-beads or glass-bubbles could increase the acoustic properties of an off-stoichiometry-thiol-enes (OSTE) based polymer. Hybrid samples with different volume fractions of glass-beads or glass-bubbles added to the OSTE polymer were manufactured and characterised according to their acoustic properties using the pulse-echo buffer-rod method. The acoustic properties measured were the density, attenuation, acoustic impedance and the reflection coefficient between water and the material. The addition of glass-beads was found to increase the acoustic impedance while the inverse was found for the addition of glass-bubbles. Both the addition of glass-beads and glass-bubbles were found to increase the attenuation. The hybrid material that was found to have the most suitable acoustic properties was OSTE/Glass-beads 40%, whose acoustic impedance had been increased ∼60% compared to pure OSTE. Consequently, the OSTE/Glass-beads 40% material was used to manufacture a microfluidic channel. A particle trapping experiment showed that the OSTE/Glass-beads 40% microfluidic channel was able to obtain bead trapping. This means that a standing wave was able to be generated within the channel and that it was strong enough to trap particles in the centre of the channel. However, evaluation of the particle trapping efficiency of the channel showed that it was not as effective as those using traditional materials. Therefore, future work is recommended to optimise a channel design for the OSTE/Glass-beads 40% material to increase the particle trapping efficiency. / I detta projekt undersöktes ett nytt hybridmaterial för användning i applikationer inom akustofores. Akustofores kan användas till att manipulera partiklar inuti mikrofluidkkanaler genom att generera ståendevågor i kanalen med hjälpav ultraljud [1]. Detta kan användas till cellseparation [2] eller till att fånga partiklar [3]. Målet i detta projekt var att skapa material som skulle bli billigare och möjliggöra enklare fabricering av kanalerna som används inom akustofores än de material som traditionellt används, med bibehållande av tillräckliga akustiskaegenskaper. Detta genomfördes genom att undersöka om tillsättning av glaspärlor eller glasbubblor kunde förbättra de akustiska egenskaperna av en off-stoichiometry-thiol-enes (OSTE) baserad polymer. Hybridprover gjorda på OSTE-polymeren med olika volymandelar av glaspärloroch glasbubblor tillverkades och kategoriserades med avseende på deras akustiska egenskaper med hjälp av pulseeko buffertstång metoden. De akustiska egenskaperna som uppmättes var densitet, attenuering, akustisk impedans och reflektions koefficienten mellan vatten och materialet. Resultatet av projektet visade att tillsättning av glaspärlor ökade den akustiska impedansen  i motsatts till glasbubblorna som visade sig minska den. Vidare visade det sig att både tillsättningen av glaspärlor och glasbubblor ökade attenueringen. Det hybridmaterial som visade sig ha de mest lämpliga akustiska egenskaperna var OSTE/glaspärlor med en 40% volymandel av glaspärlor. Den akustiska impedansen hade förhöjts med cirka 60% jämfört med vanlig OSTE. Därför valdes det hybrid-materialet till att tillverka en mikrofluidikkanal. Därefter genomfördes ett partikelfångstexperiment som visade att, OSTE/glaspärlor med en 40% volymandel av glaspärlor, kunde erhålla partikelfångst i kanalen. Detta innebär att en stående våg kunde genereras i kanalen och att den var tillräckligt stark för att kunna fånga partiklarna i mitten av kanalen. Däremot visade utvärdering av kanalens partikelfångsteffektivitet att den inte var lika effektiv som kanaler gjorda av traditionellt använda material. Därför rekommenderas framtida arbete till att designa en optimerad kanaldesign med OSTE/Glas-pärlor 40% materialets egenskaper i åtanke för att förhoppningsvis kunna öka partikelfångst effektivitet.

In 2014 SÖRAB constructed a continuous biological treatment system (KBR) to handle leachate waterfrom the landfill at the facility in Löt, north of Stockholm. The KBR is mainly focused on removal ofammonium nitrogen which would otherwise be released in to the recipient and contribute toeutrophication and damage to the environment. This project has focused on replacing the currentcarbon source in the process Brenntaplus VP1 and evaluating the efficiency of denitrification andeconomy of transitioning to a new carbon source. The carbon sources glycerol and ethanol wereevaluated and compared to Brenntaplus VP1 for the denitrification efficiency and microbial profile.The experiments were performed in laboratory conditions and in pilot scale using leachate water fromLöt. The reduction of ammonia was evaluated by chemical precipitation, addition of carbon sources bymeasuring ammonia-N and nitrate-N under aerobic (nitrification) and anaerobic (denitrification)conditions. The combination of ethanol and glycerol showed an enhanced denitrification and increasedmicrobial community both in lab and pilot scale studies with reduced hydraulic retention time. Therate of nitrate reduction was 0.23 mgNO3-N 1 -1 h -1 for ethanol/glycerol compared to 0.12-0.17mgNO 3- -N 1 -1 h -1 for Brenntaplus VP1 in pilot scale. The results indicate that using ethanol, glycerolor a mix of the two as a substitute for Brenntaplus VP1 is viable. This has been based on laboratoryand pilot scale studies. Each of the carbon sources examined during this project have showed a uniqueimpact on the process and its parameters such as: denitrification rate, microbial density and microbialcomposition. The carbon sources had an impact with temperature fluctuation and faster denitrificationcompared to the conventional KBR system. This implies that the carbon sources tested in this projectcan be advantageous and beneficial for Sörab depending on the carbon source availability and theseasonal variations. / Under 2014 konstruerade SÖRAB ett kontinuerligt biologiskt reningsverk (KBR) för att hanteralakvatten från deponin för ickefarligt avfall vid anläggningen i Löt, norr om Stockholm. KBR ärfrämst konstruerad för rening av ammoniumkväve som annars skulle släppas ut till recipienten ochbidra till övergödning och skador på miljön i området. Detta projekt har fokuserat på att ersätta dennuvarande kolkällan Brenntaplus VP1 som används i processen och utvärdera effektiviteten idenitrifieringen samt ekonomin vid övergång till en ny kolkälla. Kolkällorna glycerol och etanol varde kolkällor som valdes för utvärdering i detta projekt, dessa jämfördes med Brenntaplus VP1 i desseffekt på denitrifikationseffektivitet och mikrobiell sammansättning under laboratorieförhållanden ochi pilotskala. Möjligheten att reducera ammoniumkoncentrationen i lakvattnet utvärderades genomkemisk fällning och genom mätning av ammoniumkväve och nitratkväve under aeroba (nitrifikation)och anaeroba (denitrifikation) förhållanden. Kombinationen av etanol och glycerol indikerade enförbättrad denitrifikation och ökad mikrobiell densitet både i laboratorie- och pilotskala med reduceradhydraulisk retentionstid. Nitratreduktionshastigheten var 0,23 mgNO 3- -N 1 -1 h -1 för blandningen avetanol/glycerol jämfört med 0,12 - 0,17 mgNO 3- -N 1 -1 h -1 för Brenntaplus VP1 i pilotskala. Resultatenindikerar att användning av etanol, glycerol eller en blandning av de två har goda förutsättningar föratt ersätta Brenntaplus VP1. Var och en av de tre kolkällorna som undersöktes under detta projekt harvisat en unik inverkan på processen och dess parametrar såsom: denitrifikationshastighet, mikrobielldensitet och mikrobiell sammansättning. Genom att byta kolkälla i KBR kan prestandan ökas genomatt minska den hydrauliska retentionstiden samtidigt som systemet tycks bli mindre känsligt förtemperatursvängningar. Kolkällorna som utvärderats i detta projekt kan därför vara fördelaktiga för SÖRAB beroende på dess tillgänglighet och pris.

Groundwater (GW) accounting for most of the freshwater available around the World, finding sustainable techniques to depollute it is of crucial importance for safe drinking water supply. The extensive use of fertilizers in the agriculture, as well as other anthropogenic activities, are contributing to the excessive nitrate levels in some aquifers. These levels need to be reduced to obtain potable water. Bioelectrochemical systems (BES), using microorganisms to catalyze a desired electrochemical reaction, recently proved to be a very promising technology for water remediation. Groundwater denitrification using Microbial Electrolysis Cell (MEC) needs to be improved for further scaled-up on-site system. The advantages conferred by fluidized bed reactor (FBR), as well as the outstanding electrochemical properties of reduced graphene oxide (rGO), are two potential enhancements of such bioelectrochemical denitrification system that were investigated in this thesis. Some essential parameters could be determined during the preliminary steps' experiments. The fluidization trials gave us a clear insight that Coconut-based Activated Carbon (CAC) particles were resistant carrier particles, nicely fluidized within a 39.27cm3 circular cathodic chamber for a flow rate ranging between 450ml/min to 590ml/min. For the same flow rate of 500ml/min, we could obtain CAC particles fluidization for the upstream fluidized configuration, and still bed particles for the fixed bed downstream configuration, which would be very useful for later unbiased comparison. The denitrifying bacteria showed during their enrichment, a nitrate removal rate of up to 1.986ppm NO3-N/h in serum bottles, with an average of 0.38ppm NO2-N/h accumulation. The parallel running of fixed bed versus fluidized bed denitrifying reactor in order to compare their denitrification performances, was planned, but could not be performed due to COVID-19. The graphene oxide (GO) batch experiments showed a good biocompatibility between GO/rGO and our autotrophic denitrifying bacteria. A change of morphology within about 20 hours was observed, probably suggesting the reduction of GO to rGO by the bacteria. During a first test, the presence of GO led to a 2.7 folds less efficient denitrification performance as compared with the GO/rGO-free condition, likely due to the competition between nitrate and GO for being reduced. However, the denitrification rate in presence of GO/rGO increased up to 1.873ppm NO3-N/h after the second pulse of groundwater and flush with H2/CO2 gas, which is almost 2.3 folds higher than initially in the same condition. This suggests that GO needs some time to get fully reduced to rGO, and the denitrification rate might reach the same or higher levels as in the GO/rGO-free conditions, when GO is fully reduced. Improved denitrification would indicate that rGO facilitates the electron transfer between bacteria and nitrate, as it can be expected from its electrochemical properties previously studied. This would be worth being investigated in the scope of a longer experience. / Grundvatten (GW) som står för det mesta av det sötvatten som finns tillgängligt runt om i världen och att hitta hållbara tekniker för att förorena det är av avgörande betydelse för en trygg dricksvattenförsörjning. Den omfattande användningen av gödselmedel i jordbruket, liksom andra antropogena aktiviteter, bidrar till de överdrivna nitratnivåerna i vissa vattenfiskare. Dessa nivåer måste sänkas för att erhålla dricksvatten. Bioelektrokemiska system (BES), med användning av mikroorganismer för att katalysera en önskad elektrokemisk reaktion, visade sig nyligen vara en mycket lovande teknik för sanering av vatten. Grundvatten denitrifikation med hjälp av Microbial Electrolysis Cell (MEC) måste förbättras för att ytterligare skala upp systemet på plats. Fördelarna med fluidiserad bäddreaktor (FBR) såväl som de enastående elektrokemiska egenskaperna hos reducerad grafenoxid (rGO) är två potentiella förbättringar av ett sådant bioelektrokemiskt denitrifikationssystem som undersöktes i denna avhandling. Vissa väsentliga parametrar kan bestämmas under de preliminära stegens experiment. Fluidiseringsstudierna gav oss en klar insikt om att kokosnötbaserade aktiverade kolpartiklar (CAC) -partiklar var resistenta bärarpartiklar, trevligt fluidiserade i en cirkulär katodisk kammare på 39,27 cm3 för en flödeshastighet mellan 450ml/min till 590ml/min. För samma flödeshastighet på 500ml/min kunde vi få CAC-partikelfluidisering för uppströms fluidiserad konfiguration och stillbäddspartiklar för den fixerade bädden nedströms konfiguration, vilket skulle vara mycket användbart för senare opartisk jämförelse. De denriffriserande bakterierna visade under deras anrikning en nitratborttagningshastighet av upp till 1,986 ppm NO3-N/h i serumflaskor, med ett genomsnitt på 0,38 ppm NO2-N / h ackumulering. Den parallella körningen av denitrifierande reaktorn med fast bädd kontra fluidiserad bädd för att jämföra deras denitrifikationsprestanda planerades, men kunde inte utföras på grund av COVID-19. Diagramexperimenten av grafenoxid (GO) visade en god biokompatibilitet mellan GO/rGO och våra autotrofiska denitrifierande bakterier. En förändring av morfologin inom cirka 20 timmar observerades, vilket antagligen antydde att bakterierna minskade GO till rGO. Under ett första test ledde närvaron av GO till 2,7 gånger mindre effektiv denitrifikationsprestanda jämfört med GO/rGO-fritt tillstånd, troligtvis på grund av konkurrensen mellan nitrat och GO för att ha minskat. Denitrifikationsgraden i närvaro av GO/rGO ökade emellertid upp till 1,873 ppm NO3-N/h efter den andra grundvattenspulsen och spolades med H2/CO2-gas, vilket är nästan 2,3 gånger högre än ursprungligen i samma tillstånd. Detta antyder att GO behöver lite tid för att helt reduceras till rGO, och denitrifikationsgraden kan nå samma eller högre nivåer som i GO/rGO-fria förhållanden, när GO är helt reducerad. Förbättrad denitrifikation skulle indikera att rGO underlättar elektronöverföring mellan bakterier och nitrat, som det kan förväntas av dess elektrokemiska egenskaper som tidigare studerats. Detta skulle vara värt att undersökas inom ramen för en längre upplevelse.