Kierrätyspolttoaineiden käyttö leijukerrospoltossa vetykaasun kanssa

Tämä diplomityö on tehty Leppäkosken Energia Oy:n ja Kemira Chemicals Oy:n yhteisyritys FC Energia Oy:lle. FC Energia Oy suunnittelee rakentaa uutta bio-vetyvoimalaitosta Sastamalaan. Voimalaitoksella tuotettaisiin Kemira Chemicals Oy:n ylijäämävedystä ja biopolttoaineista sähköä, kaukolämpöä ja prosessihöyryä. Ympäristölupaa on haettu hakkeen, turpeen ja kierrätyspuun poltolle vetykaasun kanssa. Voimalaitoksen kattilan toiminta perustuu kuplivaan leijukerrostekniikkaan. Diplomityössä selvitettiin, mitä muutoksia kierrätyspolttoaineiden käyttö vaatii leijukerrospoltossa verrattuna hakkeen ja turpeen polttoon. Kierrätyspolttoaineena käytetään hyvälaatuista kierrätyspuuta. Kierrätyspuun käytössä sovelletaan jätteenpoltto-asetusta. Jätteenpolttoasetus määrää tiukemmat päästöjen raja-arvot rinnakkaispoltolle kuin hakkeen ja turpeen poltolle sekä jatkuvatoimiset savukaasujen mittauslaitteet. Rinnakkaispolton hiukkasmaisten päästöjen tiukempi raja-arvo vaatii tehokkaamman sähkösuodattimen. Lisäksi kierrätyspuuta käytettäessä tulistimen materiaaliin tulee olla kestävämpää, mikä aiheuttaa huomattavan lisäinvestoinnin. Työn päätavoitteena oli selvittää, onko kierrätyspuun käyttö taloudellisesti kannattavaa. Oletetulla kierrätyspuun hinnalla 10 €/MWh kierrätyspuuta polttavan voimalaitoksen takaisinmaksuaika on sama kuin haketta polttavan laitoksen ja vuoden lyhyempi kuin turvetta polttavan laitoksen. Tulokseksi saatiin, että rinnakkaispoltto käyttö on taloudellisesti kannattavaa hakkeenpolttoon nähden jos kierrätyspuun hinta on alle 11,2 €/MWh. Kierrätyspuun polttoon liittyy toiminnallinen riski, koska vastaavanlaisia rinnakkaispolttolaitoksia ei ole aiemmin rakennettu.

Evolution of Bioaffinity Reagents by Phage Display

Antibodies are natural binding proteins produced in vertebrates as a response to invading pathogens and foreign substances. Because of their capability for tight and specific binding, antibodies have found use as binding reagents in research and diagnostics. Properties of cloned recombinant antibodies can be further improved by means of in vitro evolution, combining mutagenesis with subsequent phage display selection. It is also possible to isolate entirely new antibodies from vast naïve or synthetic antibody libraries by phage display. In this study, library techniques and phage display selection were applied in order to optimise binding scaffolds and antigen recognition of antibodies, and to evolve new and improved bioaffinity reagents. Antibody libraries were generated by random and targeted mutagenesis. Expression and stability were mainly optimised by the random methods whereas targeted randomisation of the binding site residues was used for optimising the binding properties. Trinucleotide mutagenesis allowed design of defined randomisation patterns for a synthetic antibody library. Improved clones were selected by phage display. Capture by a specific anti- DHPS antibody was exploited in the selection of improved phage display of DHPS. Efficient selection for stability was established by combining phage display selection with denaturation under reducing conditions. Broad-specific binding of a generic anti-sulfonamide antibody was improved by selection with one of the weakest binding sulfonamides. In addition, p9 based phage display was studied in affinity selection from the synthetic library. A TIM barrel protein DHPS was engineered for efficient phage display by combining cysteinereplacement with random mutagenesis. The resulting clone allows use of phage display in further engineering of DHPS and possibly use as an alternative-binding scaffold. An anti-TSH scFv fragment, cloned from a monoclonal antibody, was engineered for improved stability to better suite an immunoassay. The improved scFv tolerates 8 – 9 °C higher temperature than the parental scFv and should have sufficient stability to be used in an immunoanalyser with incubation at 36 °C. The anti-TSH scFv fragment was compared with the corresponding Fab fragment and the parental monoclonal antibody as a capturing reagent in a rapid 5-min immunoassay for TSH. The scFv fragment provided some benefits over the conventionally used Mab in anayte-binding capacity and assay kinetics. However, the recombinant Fab fragment, which had similar kinetics to the scFv, provided a more sensitive and reliable assay than the scFv. Another cloned scFv fragment was engineered in order to improve broad-specific recognition of sulfonamides. The improved antibody detects different sulfonamides at concentrations below the maximum residue limit (100 μg/kg in EU and USA) and allows simultaneous screening of different sulfonamide drug residues. Finally, a synthetic antibody library was constructed and new antibodies were generated and affinity matured entirely in vitro. These results illuminate the possibilities of phage display and antibody engineering for generation and optimisation of binding reagents in vitro and indicate the potential of recombinant antibodies as affinity reagents in immunoassays.

Hakkuutähteestä valmistetun pyrolyysiöljyn elinkaaren kasvihuonekaasupäästöt

Kasvihuonekaasupäästöjen vähentämiseksi ja uusiutuvan energian käytön lisäämiseksi EU:ssa on säädetty direktiivi uusiutuvan energian käytön edistämisestä(RES-direktiivi). Direktiivissä annetaan ohjeet biopolttoaineiden ja bionesteiden kasvihuonekaasuvaikutusten laskemiseen. Tämän työn tarkoituksena oli selvittää, täyttääkö hakkuutähteistä valmistettu pyrolyysiöljy RES-direktiivin asettamat määrälliset vaatimukset kasvihuonekaasujen päästövähennykselle silloin, kun pyrolyysiöljyllä korvataan raskasta polttoöljyä lämmöntuotannossa. Laskenta suorittiin direktiivin ohjeiden mukaan. Lisäksi työssä pohdittiin laskentamenetelmän soveltuvuutta pyrolyysiöljyn ilmastovaikutusten arviointiin yleisesti. Laskennassa huomioitiin raaka-aineen tuotannosta, jalostuksesta sekä kuljetuksesta ja jakelusta aiheutuvat kasvihuonekaasupäästöt. Päästöt laskettiin ensin oletusarvoilla, jonka jälkeen suoritettiin todennäköisyyspohjainen herkkyystarkastelu valituille parametreille. Herkkyystarkastelun tuloksista huomattiin, että päästövähennys riippuu pääasiassa kahdesta tekijästä: maaperän hiilitaseen muutoksesta aiheutuvista päästöistä ja pyrolyysiprosessin tarvitseman lämmön tuotantoon käytetyistä polttoaineista. Eniten tuloksiin vaikutti kuitenkin se, oletettiinko pyrolysaattori ja kattila tarkastelussa erillisiksi yksiköiksi (tapaus 1) vai kokonaisuudeksi (tapaus 2). Tulosten perusteella näyttää siltä, että pyrolyysiöljyn käyttö lämmöntuotannossa raskaan polttoöljyn sijasta johtaa päästövähennyksiin. Saatuja tuloksia ei kuitenkaan voida pitää ennusteina pyrolyysiöljyn todellisista ilmastovaikutuksista, koska elinkaariarviointiin liittyy monia epävarmuuksia. RES-direktiivin laskentaohjeet esimerkiksi järjestelmärajausten muodostamisesta ja päästöjen kohdentamisesta ovat epätarkat. Tästä syystä direktiiviä on mahdollista tulkita usealla eri tavalla, jolloin toisistaan poikkeavat tulokset voivat silti olla kaikki direktiivin mukaisesti laskettuja. Jotta liika tulkinnanvaraisuus ei aiheuttaisi ongelmia, olisi RES-direktiivin laskentaohjetta hyvä tarkentaa.

Characterisation of Human Neutral and Lysosomal alpha-Mannosidases

Neutral alpha-mannosidase and lysosomal MAN2B1 alpha-mannosidase belong to glycoside hydrolase family 38, which contains essential enzymes required for the modification and catabolism of asparagine-linked glycans on proteins. MAN2B1 catalyses lysosomal glycan degradation, while neutral α-mannosidase is most likely involved in the catabolism of cytosolic free oligosaccharides. These mannose containing saccharides are generated during glycosylation or released from misfolded glycoproteins, which are detected by quality control in the endoplasmic reticulum. To characterise the biological function of human neutral α-mannosidase, I cloned the alpha-mannosidase cDNA and recombinantly expressed the enzyme. The purified enzyme trimmed the putative natural substrate Man9GlcNAc to Man5GlcNAc, whereas the reducing end GlcNAc2 limited trimming to Man8GlcNAc2. Neutral α-mannosidase showed highest enzyme activity at neutral pH and was activated by the cations Fe₂+, Co2+ and Mn₂+, Cu2+ in turn had a strong inhibitory effect on alpha-mannosidase activity. Analysis of its intracellular localisation revealed that neutral alpha-mannosidase is cytosolic and colocalises with proteasomes. Further work showed that the overexpression of neutral alpha-mannosidase affected the cytosolic free oligosaccharide content and led to enhanced endoplasmic reticulum associated degradation and underglycosylation of secreted proteins. The second part of the study focused on MAN2B1 and the inherited lysosomal storage disorder α-mannosidosis. In this disorder, deficient MAN2B1 activity is associated with mutations in the MAN2B1 gene. The thesis reports the molecular consequences of 35 alpha-mannosidosis associated mutations, including 29 novel missense mutations. According to experimental analyses, the mutations fall into four groups: Mutations, which prevent transport to lysosomes are accompanied with a lack of proteolytic processing of the enzyme (groups 1 and 3). Although the rest of the mutations (groups 2 and 4) allow transport to lysosomes, the mutated proteins are less efficiently processed to their mature form than is wild type MAN2B1. Analysis of the effect of the mutations on the model structure of human lysosomal alpha-mannosidase provides insights on their structural consequences. Mutations, which affect amino acids important for folding (prolines, glycines, cysteines) or domain interface interactions (arginines), arrest the enzyme in the endoplasmic reticulum. Surface mutations and changes, which do not drastically alter residue volume, are tolerated better. Descriptions of the mutations and clinical data are compiled in an α-mannosidosis database, which will be available for the scientific community. This thesis provides a detailed insight into two ubiquitous human alpha-mannosidases. It demonstrates that neutral alpha-mannosidase is involved in the degradation of cytosolic oligosaccharides and suggests that the regulation of this α-mannosidase is important for maintaining the cellular homeostasis of N-glycosylation and glycan degradation. The study on alpha-mannosidosis associated mutations identifies multiple mechanisms for how these mutations are detrimental for MAN2B1 activity. The α-mannosidosis database will benefit both clinicians and scientific research on lysosomal alpha‑mannosidosis.

Harvinaisten metallien talteenotto epäorgaanisista jätevirroista

Taloudellisesti tärkeiden metallien varannot ja tuotanto eivät ole jakautuneet tasaisesti. Maantieteelliset alueet, joilla ei ole omia varantoja ovat riippuvaisia muualta tuoduista raaka-aineista. Euroopan komissio ja USA:n energiaministeriö ovat luokitelleet tietyt metallit kriittisiksi niiden taloudellisen merkittävyyden ja saatavuuteen liittyvien epävarmuustekijöiden johdosta. Tällaisten metallien saatavuutta voitaisiin mahdollisesti parantaa lisäämällä niiden talteenottoa jätteistä. Tutkimuksessa kartoitettiin Euroopan komission kriittiseksi luokittelemien metallien pitoisuuksia eräissä jätevirroissa. Kartoitetut jätteet olivat teollisissa poltto-prosesseissa syntyneitä polttojätteitä, prosessiteollisuuden jätesakkoja ja sähkö- ja elektroniikkajätteitä. Kartoituksen perusteella valittiin lupaavimmat jätteet ja suoritettiin niille talteenottokokeita. Talteenottokokeita suoritettiin kolmelle jätteelle. Yhdestä jätesakasta liuotettiin indiumia rikki- ja suolahapoilla. Kahden eri polttojätteen seoksesta liuotettiin galliumia rikkihapolla. Käytettyjen loisteputkien käsittelyprosessista peräisin olleesta sakasta liuotettiin maametalleja rikki- ja suolahapoilla sekä rikki- ja typpihapon seoksella. Indium liukeni heikosti (korkeintaan 25 %) huoneenlämmössä rikkihapolla. Suolahapolla se liukeni paremmin (68 %). Polttojätteen liuotuskokeissa galliumin talteenottoasteen todettiin riippuvan käytetyn liuottimen määrästä. Loisteputkijätesakasta liukeni yttriumia ja europiumia kaikilla käytetyillä happoliuoksilla noin 70–100 %. Käytetyillä happokonsentraatioilla ei havaittu suuria eroja yttriumin ja europiumin liukoisuuksissa. Näitä metalleja voitaisiin mahdollisesti ottaa talteen tämän tyyppisestä sakasta liuottamalla ne happoliuoksella ja saostamalla oksalaattina. Tarvittaessa liuokset voitaisiin puhdistaa tai metallit erottaa toisistaan neste–nesteuutolla, joka on tärkein maametallien tuotantoon käytetty hydrometallurginen menetelmä.

Maidon ja heran mikrosuodatus

Työssä selvitettiin uudenaikaisten polymeerikalvojen soveltuvuutta maidon sekä heran mikrosuodatukseen. Kirjallisessa osassa perehdyttiin maidon ja heran koostumuksiin, mikrobikantoihin sekä erilaisiin maidon sekä heran rasvanpoisto- ja puhdistusmenetelmiin. Tämän lisäksi käsiteltiin mikrosuodatusmenetelmiä sekä niiden käyttöä heran ja maidon käsittelyssä meijeriteollisuudessa. Kokeellisessa osassa verrattiin kahdella eri suodatuslaitteistolla keraami- ja polymeerikalvojen suodatusominaisuuksia separoidun raakamaidon sekä heran poikkivirtausmikrosuodatuksessa. Tavoitteena oli erottaa suodatettavista liuoksista mikrobit sekä jäännösrasva ja tuottaa puhdasta, proteiinipitoista maitoa / heraa. Koeajoissa otetuista näytteistä analysoitiin ainesosakoostumus sekä mikrobipitoisuudet. Tuloksista määritettiin retentioarvot ja näiden perusteella vertailtiin polymeeri- ja keraamikalvojen erotustehokkuutta. Lisäksi kalvojen toimivuutta arvioitiin vuoarvojen avulla. Raakamaidon suodatuksissa polymeerikalvot pidättivät täydellisesti tai lähes täydellisesti jäännösrasvan ja mikrobit, mutta myös kaseiiniproteiinin. Tästä syystä yksikään polymeerikalvoista ei sovellu puhtaan maidon suodatukseen. Keraamikalvot soveltuvat tähän selkeästi paremmin ja yksikään toinen testatuista kalvoista ei päässyt samalle tasolle meijeriteollisuudessa jo käytössä olevan Membralox 1,4 μm -keraamikalvon kanssa. Heran suodatuksissa polymeerikalvot pidättivät täydellisesti tai lähes täydellisesti rasvan ja mikrobit, mutta keraamikalvo päästi huomattavasti enemmän haluttuja proteiineja permeaattiin. Membralox 0,8 μm -keraamikalvo pidätti täydellisesti mikrobit, mutta päästi jonkin verran jäännösrasvaa permeaattiin. Näin ollen kalvovalinta on kompromissi permeaatin puhtauden ja proteiinin saannon välillä. Keraamikalvojen vuohäviöt olivat merkittävästi pienemmät kuin polymeerikalvoilla molempien syöttöliuosten kanssa. Lisäksi keraamikalvojen puhdistus oli huomattavasti nopeampaa ja helpompaa. Tästä syystä keraamiset kalvot soveltuvat polymeerisiä paremmin maidon ja heran mikrosuodatukseen.

Hakkeen kuivaus ennen varastointia ja biopolttoaineterminaalin suunnittelu

Lempäälään aiotaan rakentaa uusi kaukolämpölaitos, jossa polttoaineena käytettäisiin haketta. Nykyään Lempäälässä tuotetaan kaukolämpöä maakaasulla, jonka käyttämisestä halutaan siirtyä käyttämään lähialueilta saatavaa biopolttoainetta. Tässä työssä halutaan selvittää, mitä hyötyjä saataisiin hakkeen koneellisesta kuivauksesta. Työn toisena tavoitteena on suunnitella ja pohtia biopolttoaineterminaalin rakentamista sekä käsitellä hakkeen varastointia yleensä. Työssä tutustutaan hakkeeseen aiheesta kertovan kirjallisuuden avulla. Työssä on myös laskettu hakkeen kuivauksesta saatavia hyötyjä hakkeen lämpöarvoon sekä energiatiheyteen. Erityisesti perehdytään metsätähdehakkeeseen, rankahakkeeseen, kuorihakkeeseen sekä sahanpuruun. Laskelmien tuloksista on havaittu, että suurin hyöty hakkeen energiatiheyden parantumisessa saadaan kun hake kuivataan 35 % kosteuspitoisuuteen. Tämän jälkeen energiatiheyden paraneminen tapahtuu hitaammin. Hakkeen kuivauksesta saadaan myös muita hyötyjä kuin energiatiheyden paraneminen. Kuivan hakkeen käsittelyn ja varastoinnin on havaittu olevan vaivattomampaa kuin märän hakkeen. Biopolttoaineterminaalin ja voimalaitoksen tulisi sijaita rinnakkain, jotta hakkeen kuivauksesta saadaan mahdollisimman kustannustehokasta. Näin ollen syntyisi myös säästöjä hakkeen kuljetuksen suhteen. Biopolttoaineterminaalin rakentamista varten tarvittaisiin tilaa alustavien laskelmien perusteella noin yksi hehtaari. Työssä on myös laskettu biopolttoaineterminaalin rakentamisesta aiheutuvia kustannuksia sekä hakkeen kuljetuksesta koituvia logistiikka kustannuksia. Haketerminaalin ja voimalaitoksen sijaintia Lempäälässä on myös kartoitettu.

Pressure filtration characteristics of enzymatically hydrolyzed biomass suspensions

Enzymatic hydrolysis of lignocellulosic polymers is likely to become one of the key technologies enabling industrial production of liquid biofuels and chemicals from lignocellulosic biomass. Certain types of enzymes are able to hydrolyze cellulose and hemicellulose polymers to shorter units and finally to sugar monomers. These monomeric sugars are environmentally acceptable carbon sources for the production of liquid biofuels, such as bioethanol, and other chemicals, such as organic acids. Liquid biofuels in particular have been shown to contribute to the reduction of net emissions of greenhouse gases. The solid residue of enzymatic hydrolysis is composed mainly of lignin and partially degraded fibers, while the liquid phase contains the produced sugars. It is usually necessary to separate these two phases at some point after the hydrolysis stage. Pressure filtration is an efficient technique for this separation. Solid-liquid separation of biomass suspensions is difficult, because biomass solids are able to retain high amounts of water, which cannot be readily liberated by mechanical separation techniques. Most importantly, the filter cakes formed from biomaterials are compressible, which ultimately means that the separation may not be much improved by increasing the filtration pressure. The use of filter aids can therefore facilitate the filtration significantly. On the other hand, the upstream process conditions have a major influence on the filtration process. This thesis investigates how enzymatic hydrolysis and related process conditions affect the filtration properties of a cardboard suspension. The experimental work consists of pressure filtration and characterization of hydrolysates. The study provides novel information about both issues, as the relationship between enzymatic hydrolysis conditions and subsequent filtration properties has so far not been considered in academic studies. The results of the work reveal that the final degree of hydrolysis is an important factor in the filtration stage. High hydrolysis yield generally increases the average specific cake resistance. Mixing during the hydrolysis stage resulted in undefined changes in the physical properties of the solid residue, causing a high filtration resistance when the mixing intensity was high. Theoretical processing of the mixing data led to an interesting observation: the average specific cake resistance was observed to be linearly proportional to the mixer shear stress. Another finding worth attention is that the size distributions of the solids did not change very dramatically during enzymatic hydrolysis. There was an observable size reduction during the first couple of hours, but after that the size reduction was minimal. Similarly, the size distribution of the suspended solids remained almost constant when the hydrolyzed suspension was subjected to intensive mixing. It was also found that the average specific cake resistance was successfully reduced by the use of filter aids. This reduction depended on the method of how the filter aids were applied. In order to obtain high filtration capacity, it is recommended to use the body feed mode, i.e. to mix the filter aid with the slurry prior to filtration. Regarding the quality of the filtrate, precoat filtration was observed to produce a clear filtrate with negligible suspended solids content, while the body feed filtrates were turbid, irrespective of which type of filter aid was used.

AQUAREL CONCEPT Aquatic resources for green energy realization

The AQUAREL project studied the availability and optional utilization methods for fish processing side streams and other aquatic biomaterial in the Republic of Karelia. Additionally processing aquatic biomaterial with manure and sewage sludge was studied. Based on the results, the most feasible option today is to process fish side streams to fish oil and dewatered oil-free residue and to use them for fish or animal feed production. However, it is necessary to highlight, that changes in e.g. economic environment, energy prices and demand may require re-evaluating the results and conclusions made in the project. Producing fish oil from fish processing side streams is an easy and relatively simple production process generating a valuable end product. The functionality of the process was confirmed in a pilot conducted in the project. The oil and solids are separated from the heated fish waste based on gravity. The fish oil separating on top of the separator unit is removed. Fish oil can as such be utilized for heating purposes, fish meal or animal feed production, but it can also be further processed to biodiesel. However, due to currently moderate energy prices in Russia, biodiesel production is not economically profitable. Even if the fish oil production process is not complicated, the operative management of small-scale fish oil production unit requires dedicated resources and separate facilities especially to meet hygiene requirements. Managing the side streams is not a core business for fish farmers. Efficient and economically profitable fish oil production requires a centralized production unit with bigger processing capacity. One fish processing unit needs to be designed to manage side streams collected from several fish farms. The optimum location for the processing unit is in the middle of the fish farms. Based on the transportation cost analysis in the Republic of Karelia, it is not economically efficient to transport bio-wastes for more than 100 km since the transportation costs start increasing substantially. Another issue to be considered is that collection of side streams, including the dead fish, from the fish farms should be organized on a daily basis in order to eliminate the need for storing the side streams at the farms. Based on AQUAREL project studies there are different public funding sources available for supporting and enabling profitable and environmentally sustainable utilization, research or development of fish processing side streams and other aquatic biomaterial. Different funding programmes can be utilized by companies, research organizations, authorities and non-governmental organizations.

Unraveling the functional divergence of membrane-bound pyrophosphatases

Inorganic pyrophosphatases (PPases) are enzymes that hydrolyze pyrophosphate (PPi)which is produced as a byproduct in many important growth related processes e.g. in the biosynthesis of DNA, proteins and lipids. PPases can be either soluble or membranebound. Membrane-bound PPases (mPPases) are ion transporters that couple the energy released during PPi hydrolysis to Na+ or H+ transport. When I started the project, only three Na+-transporting mPPases were known to exist. In this study, I aimed to confirm if Na+-transport is a common function of mPPases. Furthermore, the amino acid residues responsible for determining the transporter specificity were unknown. I constructed a phylogenetic tree for mPPases and selected the representative bacterial and archaeal mPPases to be investigated. I expressed different prokaryotic mPPases in Escherichia coli, isolated these as inverted membrane vesicles and characterized their functions. In the first project I identified four new Na+-PPases, two K+-dependent H+-PPases and one K+-independent mPPase. The residues determining the transporter specificity were identified by site-directed mutagenesis. I showed that the conserved glutamate residues are important for specificity, though are not the only residues that influence it. This research clarified the ion transport specificities throughout the mPPase phylogenetic tree, and revealed that Na+ transport is a widespread function of mPPases. In addition, it became clear that the transporter specificity can be predicted from the amino acid sequence in combination with a phylogenetic analysis. In the second project, I identified a novel class of mPPases, which is capable of transporting both Na+ and H+ ions and is mainly found in bacteria of the human gastrointestinal tract. The physiological role of these novel enzymes may be to help the bacteria survive in the demanding conditions of the host. In the third project, I characterized the Chlorobium limicola Na+-PPase and found that this and related mPPases are able to transport H+ ions at subphysiological Na+ concentrations. In addition, the H+-transport activity was shown to be a common function of all studied Na+-PPases at low Na+ concentrations. I observed that mutating gate-lysine to asparagine eliminated the H+ but not the Na+ ion transport function, indicating the important role of the residue in the transport of H+. In the fourth project, I characterized the unknown and evolutionary divergent mPPase clade of the phylogenetic tree. The enzymes belonging to this clade are able to transport H+ ions and, based on their sequence, were expected to be K+- and Na+-independent. The sequences of membrane-bound PPase are usually highly conserved, but the enzymes belonging to this clade are more divergent and usually contain 100−150 extra amino acid residues compared to other known mPPases. Despite the vast sequence differences, these mPPases have the full set of important residues and, surprisingly, are regulated by Na+ and K+ ions. These enzymes are mainly of bacterial origin.

Bauksiittijätteen neutralointi- ja stabilointimenetelmät

Bauksiittijäte on alumiinin jalostuksessa syntyvä sivutuote, jonka alkalisuus on riski lähiympäristön ekosysteemeille. Alkalisuuden aiheuttamaan riskiin etsittiin ratkaisua perehtymällä bauksiittijätteen käsittelyyn. Kandidaatintyössä esitettiin eri menetelmiä bauksiittijätteen neutraloimiseksi, stabiloimiseksi ja varastoimiseksi. Menetelmien periaatteet määritettiin kirjallisuudesta löytyvien tutkimusten pohjalta, joiden perusteella voitiin määrittää toimivimmat menetelmät bauksiittijätteen käsittelemiseksi. Käytännöllisimmiksi käsittelymenetelmiksi osoittautuivat meriveden ja/tai hiilidioksidin lisääminen bauksiittijätteeseen sen neutraloimiseksi. Bauksiittijätteen stabiloimiseksi siihen tulee lisätä kiinteää materiaalia, kuten kalkkia, kiintoainepitoisuuden nostamiseksi sekä kovettuvien yhdisteiden muodostumiseksi.

VAP-1 as drug target in inflammation : structural features determining ligand interactions

Vascular adhesion protein-1 (VAP-1), which belongs to the copper amine oxidases (CAOs), is a validated drug target in inflammatory diseases. Inhibition of VAP-1 blocks the leukocyte trafficking to sites of inflammation and alleviates inflammatory reactions. In this study, a novel set of potent pyridazinone inhibitors is presented together with their X-ray structure complexes with VAP-1. The crystal structure of serum VAP-1 (sVAP-1) revealed an imidazole binding site in the active site channel and, analogously, the pyridazinone inhibitors were designed to bind into the channel. This is the first time human VAP-1 has been crystallized with a reversible inhibitor and the structures reveal detailed information of the binding mode on the atomic level. Similarly to some earlier studied inhibitors of human VAP-1, the designed pyridazinone inhibitors bind rodent VAP-1 with a lower affinity than human VAP-1. Therefore, we made homology models of rodent VAP-1 and compared human and rodent enzymes to determine differences that might affect the inhibitor binding. The comparison of the crystal structures of the human VAP-1 and the mouse VAP-1 homology model revealed key differences important for the species specific binding properties. In general, the channel in mouse VAP-1 is more narrow and polar than the channel in human VAP-1, which is wider and more hydrophobic. The differences are located in the channel leading to the active site, as well as, in the entrance to the active site channel. The information obtained from these studies is of great importance for the development and design of drugs blocking the activity of human VAP-1, as rodents are often used for in vivo testing of candidate drugs. In order to gain more insight into the selective binding properties of the different CAOs in one species a comprehensive evolutionary study of mammalian CAOs was performed. We found that CAOs can be classified into sub-families according to the residues X1 and X2 of the Thr/Ser-X1-X2-Asn-Tyr-Asp active site motif. In the phylogenetic tree, CAOs group into diamine oxidase, retina specific amine oxidase and VAP-1/serum amine oxidase clades based on the residue in the position X2. We also found that VAP-1 and SAO can be further differentiated based on the residue in the position X1. This is the first large-scale comparison of CAO sequences, which explains some of the reasons for the unique substrate specificities within the CAO family.

Effect of Material Recycling on the Feasibility of Solid Recovered Fuel Fired Power Plant

This master’s thesis examines the effects of increased material recycling on different waste-to-energy concepts. With background study and a developed techno-economic computational method the feasibility of chosen scenarios with different combinations of mechanical treatment and waste firing technologies can be evaluated. The background study covers the waste scene of Finland, and potential market areas Poland and France. Calculated cases concentrate on municipal solid waste treatment in the Finnish operational environment. The chosen methodology to approach the objectives is techno-economic feasibility assessment. It combines calculation methods of literature and practical engineering to define the material and energy balances in chosen scenarios. The calculation results together with other operational and financial data can be concluded to net present values compared between the scenarios. For the comparison, four scenarios, most vital and alternative between each other, are established. The baseline scenario is grate firing of source separated mixed municipal solid waste. Second scenario is fluidized bed combustion of solid recovered fuel produced in mechanical treatment process with metal separation. Third scenario combines a biomaterial separation process to the solid recovered fuels preparation and in the last scenario plastics are separated in addition to the previous operations. The results indicated that the mechanical treatment scenarios still need to overcome some problems to become feasible. Problems are related to profitability, residue disposal and technical reliability. Many uncertainties are also related to the data gathered over waste characteristics, technical performance and markets. With legislative support and development of further processing technologies and markets of the recycled materials the scenarios with biomaterial and plastic separation may operate feasibly in the future.

Probing MST1 Kinase Sequence and Structure for Rational Drug Discovery (Targeting diabetes by blocking protein-protein interactions)

Apoptotic beta cell death is an underlying cause majorly for type I and to a lesser extent for type II diabetes. Recently, MST1 kinase was identified as a key apoptotic agent in diabetic condition. In this study, I have examined MST1 and closely related kinases namely, MST2, MST3 and MST4, aiming to tackle diabetes by exploring ways to selectively block MST1 kinase activity. The first investigation was directed towards evaluating possibilities of selectively blocking the ATP binding site of MST1 kinase that is essential for the activity of the enzymes. Structure and sequence analyses of this site however revealed a near absolute conservation between the MSTs and very few changes with other kinases. The observed residue variations also displayed similar physicochemical properties making it hard for selective inhibition of the enzyme. Second, possibilities for allosteric inhibition of the enzyme were evaluated. Analysis of the recognized allosteric site also posed the same problem as the MSTs shared almost all of the same residues. The third analysis was made on the SARAH domain, which is required for the dimerization and activation of MST1 and MST2 kinases. MST3 and MST4 lack this domain, hence selectivity against these two kinases can be achieved. Other proteins with SARAH domains such as the RASSF proteins were also examined. Their interaction with the MST1 SARAH domain were evaluated to mimic their binding pattern and design a peptide inhibitor that interferes with MST1 SARAH dimerization. In molecular simulations the RASSF5 SARAH domain was shown to strongly interact with the MST1 SARAH domain and possibly preventing MST1 SARAH dimerization. Based on this, the peptidic inhibitor was suggested to be based on the sequence of RASSF5 SARAH domain. Since the MST2 kinase also interacts with RASSF5 SARAH domain, absolute selectivity might not be achieved.

Optimal Recycling Combination of Ash in South-East Finland

The present world energy production is heavily relying on the combustion of solid fuels like coals, peat, biomass, municipal solid waste, whereas the share of renewable fuels is anticipated to increase in the future to mitigate climate change. In Finland, peat and wood are widely used for energy production. In any case, the combustion of solid fuels results in generation of several types of thermal conversion residues, such as bottom ash, fly ash, and boiler slag. The predominant residue type is determined by the incineration technology applied, while its composition is primarily relevant to the composition of fuels combusted. An extensive research has been conducted on technical suitability of ash for multiple recycling methods. Most of attention was drawn to the recycling of the coal combustion residues, as coal is the primary solid fuel consumed globally. The recycling methods of coal residues include utilization in a cement industry, in concrete manufacturing, and mine backfilling, to name few. Biomass combustion residues were also studied to some extent with forest fertilization, road construction, and road stabilization being the predominant utilization options. Lastly, residues form municipal solid waste incineration attracted more attention recently following the growing number of waste incineration plants globally. The recycling methods of waste incineration residues are the most limited due to its hazardous nature and varying composition, and include, among others, landfill construction, road construction, mine backfilling. In the study, environmental and economic aspects of multiple recycling options of thermal conversion residues generated within a case-study area were studied. The case-study area was South-East Finland. The environmental analysis was performed using an internationally recognized methodology — life cycle assessment. Economic assessment was conducted applying a widely used methodology — cost-benefit analysis. Finally, the results of the analyses were combined to enable easier comparison of the recycling methods. The recycling methods included the use of ash in forest fertilization, road construction, road stabilization, and landfill construction. Ash landfilling was set as a baseline scenario. Quantitative data about the amounts of ash generated and its composition was obtained from companies, their environmental reports, technical reports and other previously published literature. Overall, the amount of ash in the case-study area was 101 700 t. However, the data about 58 400 t of fly ash and 35 100 t of bottom ash and boiler slag were included in the study due to lack of data about leaching of heavy metals in some cases. The recycling methods were modelled according to the scientific studies published previously. Overall, the results of the study indicated that ash utilization for fertilization and neutralization of 17 600 ha of forest was the most economically beneficial method, which resulted in the net present value increase by 58% compared to ash landfilling. Regarding the environmental impact, the use of ash in the construction of 11 km of roads was the most attractive method with decreased environmental impact of 13% compared to ash landfilling. The least preferred method was the use of ash for landfill construction since it only enabled 11% increase of net present value, while inducing additional 1% of negative impact on the environment. Therefore, a following recycling route was proposed in the study. Where possible and legally acceptable, recycle fly and bottom ash for forest fertilization, which has strictest requirements out of all studied methods. If the quality of fly ash is not suitable for forest fertilization, then it should be utilized, first, in paved road construction, second, in road stabilization. Bottom ash not suitable for forest fertilization, as well as boiler slag, should be used in landfill construction. Landfilling should only be practiced when recycling by either of the methods is not possible due to legal requirements or there is not enough demand on the market. Current demand on ash and possible changes in the future were assessed in the study. Currently, the area of forest fertilized in the case-study are is only 451 ha, whereas about 17 600 ha of forest could be fertilized with ash generated in the region. Provided that the average forest fertilizing values in Finland are higher and the area treated with fellings is about 40 000 ha, the amount of ash utilized in forest fertilization could be increased. Regarding road construction, no new projects launched by the Center of Economic Development, Transport and the Environment in the case-study area were identified. A potential application can be found in the construction of private roads. However, no centralized data about such projects is available. The use of ash in stabilization of forest roads is not expected to increased in the future with a current downwards trend in the length of forest roads built. Finally, the use of ash in landfill construction is not a promising option due to the reducing number of landfills in operation in Finland.