HarpinPss, a proteinaceous elicitor from Pseudomonas syringae pv. syringae, is a glycine-rich, cysteine-lacking, heat-stable protein. It can elicit the hypersensitive response (HR) when delivered to the surface of plant cells. HRAP (hypersensitive response assisting protein) is an amphipathic protein purified from sweet pepper and could intensify harpinPss¡Vmediated HR in sweet pepper. In the previous research, harpinPss was present as monomer, dimer, trimer, tetramer, and ocatamer forms in neutral pH buffer. Only monomer and dimer forms of harpinPss induced hypersensitive response in nonhost plants. HRAP could cause multimeric forms of harpinPss dissociation into monomer forms. The interaction between HRAP and harpinPss is an important issue. HRAP contained three positively charged regions, a typical signal peptide and a cAMP-dependent phosphorylation site. In this study, these regions of HRAP would be truncated and identified whether these truncated HRAP fragments could promote harpinPss dissociation. Different combinations of truncated HRAP and harpinPss were used to identify the protein-interaction regions between two proteins. HarpinPss triggers HR via interaction with cAMP phosphorated region of HRAP and MAPK pathway transduction. When cAMP region of HRAP was truncated, harpinPss still triggers HR via polymerization and anchor on lipid bilayers to form an ion-conducting pore.

La présente thèse porte sur des travaux expérimentaux et de modélisation visant à étudier les processus bactériens et algaux au sein d’une lagune a haut rendement algal (HRAP). Un système pilote HRAP a été construit et les impacts des différentes conditions opérationnelles sur l’hydrodynamique et le transfert gaz/liquide du pilote ont été étudiés. De plus, le rapport d'inoculation optimal entre les algues et les bactéries (Al-Bac) a également été étudié. La biomasse Al-Bac a ensuite été inoculée dans le système HRAP pour une évaluation à long terme du traitement des eaux usées et de la récupération des nutriments. Le HRAP dans cette étude peut être appliqué en traitement secondaire de eaux usées ou comme étape primaire éliminant rapidement les charges élevées de DCO et de TKN des retour en tête de digesteurs anaérobies (centrats). Les résultats expérimentaux obtenus ont également été utilisés pour calibrer et valider des modèles de type « boîte noire » et mécanistes. Les deux modèles peuvent décrire le fonctionnement à long terme du système. Le premier permet ainsi d'évaluer rapidement les performances du système ainsi que de le dimensionner, tandis que le second simule avec succès les résultats à long (général) et à court (détaillé) terme. L'étape suivante devrait être l'application du système à grande échelle. / The thesis focused on both experimental and modeling works aiming to investigate the algal bacterial processes in High-Rate Algal Pond (HRAP) system. A pilot HRAP system was built and the impacts of different operational conditions on hydraulic and gas transfer rate of the pilot were investigated. Moreover, optimal inoculation ratio between algae and bacteria (Al-Bac) was also studied. The Al-Bac biomass was theninoculated in the HRAP system for long term assessment of wastewater treatment and nutrient recovery. The HRAP in this study can be applied for secondary treatment application or as a primary step removing rapidly high loads of COD and TKN from centrate wastewater. Experimental results obtained were also employed in calibrating and validating black box and comprehensive algal bacterial models. Both models coulddescribe the system in long term. The former was adequate for giving quick assessment of the system performance as well as sizing application while the latter successfully simulated the results both in long (general) and short (detailed) time scale. A next step should be applying the system in large scale.

Syftet var att finna en biologisk behandlingsmetodik för avloppsvatten som skullekunna reducera utsläpp av näringsämnen till recipienten Humlebäcken frånavloppsreningsverket (ARV) i Nyvång. Nyvångs reningsverk planeras uppgraderas och utökas och därtill har ärendet nekats då utsläpp till Humlebäcken förfaras bli för höga. Mikroalger som behandlingsmetod för avloppsvatten undersöktes via litteraturanalys ibåde svenska klimat och vid uppskalning. Det kunde inte hittas metodik eller teknik för att på industriell skala använda mikroalger till behandling av avloppsvatten idag. Dock presenteras flera olika tekniker som kan kopplas samman för ökad effektivitet. Vidare finns det stor potential om att mikroalgssystem kan kopplas samman med andra industriers spillvärme och rökgaser för ökad produktion av biomassa och rening av rökgas. Andra former av kemisk försedimentering och anaerob behandling från Energipositiv Rening presenteras, möjligheten finns att dessa kan kopplas samman med mikroalgssystem för komplett behandling till lägre kostnader av konventionell behandlingsteknik. Till slut presenteras påverkande faktorer vid nordiska klimat och utmaningar i form av striktare reningskrav och återföring av slam. Det presenteras kort om andra biologiska tekniker som svampodling och multitrofiskt vattenbruk vilka kan kopplas samman medmikroalgssystem för ökad resurseffektivitet och högre reningsgrad. Se figur 18 förgrafisk summering. / The purpose was to find a biological treatment method for wastewater which could reduce emissions of nutrients to the recipient Humlebäcken from the wastewater treatment plant (WWTP) in Nyvång. Since Nyvång WWTP plans to upgrade and expand have been denied for fears of further contamination of Humlebäcken. Microalgae as a treatment method was examined in this literature analysis for Swedish climates and upscaling. For industrial purposes no technique or method could befound which could be applied to wastewater currently. Several techniques are presented however in the hopes that in combining them a higher efficiency might beachieved. If microalgae systems could be integrated with waste heat and flue gas from industry, then higher productivity could be achieved whilst reducing emissions from the flue gas. Other forms of pre-sedimentation and anaerobic treatment methods from EnergyPositive Purification systems are presented as there's a possibility these can be connected to microalgae systems for complete treatment and less costs. Factors which affect microalgae cultivation in Nordic climates and challenges in terms of stricter emission requirements and reuse of sludge are presented lastly. Other biological treatment methods like mushroom and multi-trophic aquaculture which can be integrated to microalgae systems are shown in hopes of achieving higher resource efficiency and pollution reduction. See figure 18 for graphical abstract.

Coal seams are commonly associated with poor quality water that requires treatment. Water treatment can be very expensive and can severely affect the profitability of mining projects. This study investigated the potential cultivation of Arthrospira maxima (Spirulina) in coal seam water to beneficiate coal seam water in order to effectively offset the water treatment cost. The study was conducted in Northern South Africa and formed part of a larger Coal Seam Water Beneficiation Project (CSWBP). The study consisted of laboratory based Flask Studies and outdoor High Rate Algal Pond Studies. The Flask Studies that were carried out in the on-site field laboratory, found that the coal seam water could provide a suitable medium for Spirulina cultivation. In addition, it was found that the optimal pH for the selected strain ranged between 9 - 10.5 and that the addition of excess iron, up to 100 times the concentration found in defined growth media such as Schlösser’s, to the culture media could enhance productivity. The High Rate Algal Pond Studies (HRAP) were carried out over a period of 18 months. The studies showed that the coal seam water at the CSWBP is a valuable resource that can reduce media costs by 50% without affecting productivity. In a study encompassing 334 days it was shown that heating the culture through plate heat exchangers would result in a significant increase in productivity and a heated productivity of 19.86 g/m2/day was recorded. An unheated productivity of 14.11 g/m2/day was recorded. Therefore, it was found that it would be economically feasible to beneficiate coal seam water found at the CSWBP through the cultivation of Arthrospira maxima (Spirulina). / Environmental Sciences / M. Sc. (Environmental Science)

Coal seams are commonly associated with poor quality water that requires treatment. Water treatment can be very expensive and can severely affect the profitability of mining projects. This study investigated the potential cultivation of Arthrospira maxima (Spirulina) in coal seam water to beneficiate coal seam water in order to effectively offset the water treatment cost. The study was conducted in Northern South Africa and formed part of a larger Coal Seam Water Beneficiation Project (CSWBP). The study consisted of laboratory based Flask Studies and outdoor High Rate Algal Pond Studies. The Flask Studies that were carried out in the on-site field laboratory, found that the coal seam water could provide a suitable medium for Spirulina cultivation. In addition, it was found that the optimal pH for the selected strain ranged between 9 - 10.5 and that the addition of excess iron, up to 100 times the concentration found in defined growth media such as Schlösser’s, to the culture media could enhance productivity. The High Rate Algal Pond Studies (HRAP) were carried out over a period of 18 months. The studies showed that the coal seam water at the CSWBP is a valuable resource that can reduce media costs by 50% without affecting productivity. In a study encompassing 334 days it was shown that heating the culture through plate heat exchangers would result in a significant increase in productivity and a heated productivity of 19.86 g/m2/day was recorded. An unheated productivity of 14.11 g/m2/day was recorded. Therefore, it was found that it would be economically feasible to beneficiate coal seam water found at the CSWBP through the cultivation of Arthrospira maxima (Spirulina). / Environmental Sciences / M. Sc. (Environmental Science)