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Atomic layer deposition (ALD) is a layer-by-layer deposition process based on repeated self-limiting gas-solid reactions by using volatile precursors. It is suited for producing dense and pinhole-free inorganic nanoscale coatings uniform in thickness at relatively low temperatures. The purpose of this presentation is to demonstrate the potential and the challenges of using ALD to create functional coatings for polymer films. ALD is an efficient tool for improving the barrier properties of polymer films. However, adequate barrier properties are only one of the key requirements set for the packaging materials. As far as safety issues are concerned, these coatings, for example, seem not to fall under the European definition of nanotechnology and migration is low enough to meet the requirements set by current European regulations. ALD can also be used to create antimicrobial coatings, and thin oxide coatings can be modified for improved mechanical and surface properties. It is recommended that ALD coatings are protected with an additional polymer layer providing also heat sealability. Although ALD is today carried out in batch mode, the development of roll-to-roll processes will enhance the feasibility of ALD for e.g. packaging materials

Atomic layer deposition (ALD) is a surface controlled layer-by-layer process based on self-limiting gas-solid reactions. Thin films are prepared using volatile precursors in repeating cycles until a preferred film thickness is obtained. ALD is suited for producing dense and pinhole-free inorganic films uniform in thickness. Most important commercial applications lies today in microelectronics, but they range from displays to protective coatings on silver jewellery. The purpose of this presentation is to demonstrate both the potential and the challenges of using ALD to create thin barrier layers for packaging materials. ALD can have a profound effect on the barrier values of various polymer films and polymer coated paperboards. As far as safety issues are concerned, these thin barrier films seem not to fall under the European definition of nanotechnology and migration is low enough to meet the requirements set by current European regulations. ALD can also be used to create antimicrobial thin films, and thin oxide films can be modified for improved mechanical and surface properties. It is recommended that ALD deposited thin films are protected with an additional polymer layer also providing heat sealability. Although ALD is today carried out in batch mode, the development of roll-to-roll processes will enhance the techno-economic feasibility of ALD, among others, for packaging materials.

Kehäradan tunneliin tunkeutunut glykoli ja syntynyt mikrobikasvusto yllätti rakentajat vuonna 2010. Seurannan ja tutkimusten perusteella paikannetulle vuotoalueelle rakennetaan haitat eliminoiva suojarakenne. Kirjoituksessa tarkastellaan glykolivuotojen ja syntyvien mikrobikasvustojen rakennusmateriaaleille kohdistamia uhkia ja materiaalien säilyvyyttä syntyneissä olosuhteissa.

The proposed disposal concept for high-level radioactive wastes involves storing the wastes underground in copper-iron containers embedded in buffer material of compacted bentonite. Hydrogen sulphide production by sulphate-reducing prokaryotes is a potential mechanism that could cause corrosion of waste containers in repository conditions. The prevailing conditions in compacted bentonite buffer will be harsh. The swelling pressure is 7-8 MPa, the amount of free water is low and the average pore and pore throat diameters are small. This literature study aims to assess the potential of microbial activity in bentonite buffers. Literature on the environmental limits of microbial life in extreme conditions and the occurrence of sulphate-reducing prokaryotes in extreme environments is reviewed briefly and the results of published studies characterizing microbes and microbial processes in repository conditions or in relevant subsurface environments are presented. The presence of bacteria, including SRBs, has been confirmed in deep groundwater and bentonite-based materials. Sulphate reducers have been detected in various high-pressure environments, and sulphate-reduction based on hydrogen as an energy source is considered a major microbial process in deep subsurface environments. In bentonite, microbial activity is strongly suppressed, mainly due to the low amount of free water and small pores, which limit the transport of microbes and nutrients. Spore-forming bacteria have been shown to survive in compacted bentonite as dormant spores, and they are able to resume a metabolically active state after decompaction. Thus, microbial sulphide production may increase in repository conditions if the dry density of the bentonite buffer is locally reduced.

Biojalostamossa hyödynnetään biomassaa fossiilisista raaka-aineista valmistettuja tuotteita korvaavien biopolttoaineiden, bioenergian ja kemikaalien tuotannossa. Esimerkiksi sokeri-, tärkkelys- ja selluloosapitoisista materiaaleista voidaan valmistaa entsymaattisen hydrolyysin ja bioteknisen prosessoinnin avulla etanolia tai kemikaaleja. Biomassaa hyödynnetään laajenevassa mitassa polttoaineiden tuotannossa, mutta kemianteollisuus perustuu toistaiseksi lähes yksinomaan fossiilisten raaka-aineiden käyttöön. Tässä hankkeessa selvitettiin yhdyskuntajätteen hyödyntämismahdollisuuksia biojalostamo-konseptissa käyttäen malliprosessina polttoaine-etanolin tuottoa. Yhdyskuntien jätevirtojen kartoituksen perusteella valittiin sokerireittiin perustuvan biojalostamon raaka-aineeksi soveltuvat, runsaasti hiilihydraatteja sisältävä fraktiot, joiden soveltuvuutta biotekniseen jatkokäsittelyyn tutkittiin laboratoriomittakaavan kokeissa. Soveltuvia jätefraktioita ovat erilliskerätty biojäte, sekajäte, kuitupakkaukset, keräyspaperi ja rakennusjätteen tietyt fraktiot. Osalle näistä jakeista on jo olemassa toimivat hyödyntämisjärjestelmät, joten ne jätettiin tämän selvityksen ulkopuolelle. Saatujen tulosten mukaan erilliskerätty biojäte soveltuu teknisesti erittäin hyvin sokereita hyödyntävän biojalostamon raaka-aineeksi. Erilliskerätyn biojätteen volyymit ovat kuitenkin pieniä: YTV-alueen biojätteen käyttävä laitos tuottaisi 3 000 tonnia etanolia vuodessa, ja kokonaisetanolintuottopotentiaali biojätteestä Suomessa on alle 20 000 tonnia vuodessa. Kaatopaikoille menevä sekajäte on volyymiltaan biojätettä huomattavasti suurempi jätefraktio. Hiilihydraattikoostumuksen perusteella arvioiden Suomen sekajätekertymästä olisi teoreettisesti mahdollista tuottaa 260 000 tonnia etanolia vuodessa. Sekajätteen heterogeenisuus vaikeuttaa hiilihydraattien hyödyntämistä, ja tässä työssä saatujen tulosten perusteella saanto fraktioimattomaan sekajätteeseen perustuvassa prosessissa ilmeisesti olisi alle 50 % teoreettisesta. Sekajätteen tehokas hyödyntäminen sokerireittiin perustuvassa biojalostamoissa edellyttääkin raaka-aineen fraktiointia joko keräyksen yhteydessä tai jätteenkäsittelylaitoksessa ja prosessien edelleen kehittämistä, muun muassa esikäsittelyjen optimointia.

By combining atmospheric pressure plasma technology with nano-sized (electrostatic) precursor addition, an in-line production process for the deposition of high-performance, multi-functional barrier coatings on plastic foils could be developed. It has been demonstrated that the basic concept of plasma assisted curing and in-situ deposition of nano-sized precursors of sol-gel systems is superior over conventional thermal or UV curing of wet-chemically applied coatings. The barrier properties that could be obtained were within the range of currently available atmospheric technologies (EVOH coating and PVdC lamination) and the most commonly used vacuum technology (evaporation of a thin aluminium coating). Advantages of the newly developed technology include the improved flexibility to implement the coating process in-line (especially compared to vacuum processes), the possibility to apply other functional or multifunctional coatings using the same equipment and the fact that the process is environment friendly since no solvents are used. The combination of tailored chemical surface activation by means of cold atmospheric plasma treatment and subsequent wet-chemical coating using a chitosan solution resulted in coated plastic foils with good anti-microbial activity and improved barrier properties against oxygen transmission. Chitosan is a food approved compound derived from chitin, the second most abundant natural polymer after cellulose. The reduction of bacterial growth observed, indicates that the amount of preservatives can be reduced significantly by applying this type of treatment.

Slime biofilms consist of microbial populations attached to a surface and embedded within matrix containing extracellular polysaccharides (EPS) which forms the major structural component of the biofilm. The presence of biofilm protects the contaminating micro-organisms against biocides to a certain extent. The enzymatic degradation mechanisms of these polysaccharides have not been largely studied, partly because of their branched and complex polymeric structure. In this work novel enzymes for slime EPS degradation have been isolated and their suitability for slime control in the paper industry is being established. Slime producing organisms were first isolated from different paper machine environments using chemical pulp, CTMP, mechanical pulp and recycled pulp as raw material. Bacteria were isolated from the paper machine slimes using the ability to form slimy colonies on glucose containing solid medium as criterion for slime production. Totally 43 bacterial isolates were obtained. Of the strains at least 14 belonged to the Enterohacteriaceae and 9 to the aerobic spore-forming bacteria (Bacillus, Paenibacillus. Brevibacillus). Bacteria belonging to the family Enterobacteriaceae have been found especially from the deposits in a mill in Finland but also in the Spanish mills. Non-enterobacterial gram-negative slime-producers isolated include Brevundimonas vesicularis, Methylobacterium sp. and Pseudomonas aeruginosa. Polysaccharides were produced in shake flasks using 35 strains isolated. The strains were cultivated for 5-6d with measurement of culture medium viscosity during the cultivation. Of the 35 strains used significant viscosity increase was observed by 12 strains. In most cases the type of nitrogen source (organic/inorganic) did not have significant effect on polysaccharide production. The slime polysaccharides were precipitated by ethanol whereafter their chemical composition was analysed by HPLC. A more detailed structural analysis of the produced polysaccharides was carried out using HPSEC and GC-MS. With the exception of one homogalactan, the polysaccharides produced were heteropolysaccharides with various monosaccharide compositions. The structure of selected EPS have been characterised using advanced analytical techniques. Microbial cultures capable of degrading the isolated bacterial polysaccharides were enriched from soil and compost samples by incubating the samples in medium containing the respective polysaccharide as the only carbon source. The methodology for screening of exopolysaccharide producing enzymes and their effect on biofilm structure has been proved in the case of Klebsiella pneurnoniae originally isolated from a paper machine biofilm. Degradation of polysaccharide was detected as reduction of culture medium viscosity. All the composts used for enrichment appeared to be good sources of cultures degrading polysaccharides of bacteria from paper machines. The polysaccharide-degrading cultures obtained were multi-species mixed populations. The most potential EPS degrading enzymes have been purified and their mode of action is being investigated. Due to the complex composition of slimes it is expected that these new enzymes can most efficiently be used in combinations of several effective enzymes, possibly also with synergistic use of dispersing agents.

Chitosan coatings prominently improved both the gloss and oxygen barrier properties of paper. The gloss value in the machine direction was increased as a function of added chitosan. An oxygen‐permeability value of 1.1 cm3/m2 d was obtained when 6.9 g/m2 chitosan was applied to 80 g/m2 copy paper. In addition, the effects on the mechanical properties were positive, but not significant. The water‐vapor permeability of the paper increased as a result of the chitosan coating. Chitosan dissolved in 1.6, 3.2, and 6.4% lactic acid showed antimicrobial activity against Bacillus subtilis, whereas acetic and propionic acids (1.6, 3.2, and 6.4%) did not produce any notable activity. Nisin (0.08 g/L) did not enhance the antimicrobial activity of coatings prepared from chitosan dissolved in different acids.

An inert carrier (nylon sponge), a non-inert carrier (barley straw) and the addition of veratryl alcohol or manganese (IV) oxide to the cultures were used to study the production of ligninolytic enzymes by Phanerochaete chrysosporium BKM-F-1767 (ATCC 24725) during semi solid state fermentation conditions. By supplementing the medium with these compounds we could stimulate the ligninolytic system of this fungus. The different carriers employed and the effect of adding veratryl alcohol or manganese (IV) oxide to the cultures were compared in order to determine the best system to produce high activities of ligninolytic enzymes. Lignin peroxidase (LiP) activities higher than 500 U/L and manganese-dependent peroxidase (MnP) activities about 1100 U/L were achieved.

Trichoderma strains were screened for siderophore production and the antimicrobial activities of the crude siderophore preparations against various fungi were compared. The siderophores of T. harzianum strains CBS 243.71 and VTT-D-80150 were most promising and were selected for further studies. The siderophores were purified from culture filtrates using gel-filtration and ion exchange chromatography and the antimicrobial activities of the purified siderophores against molds, yeasts and wood rotting fungi were assayed. T. harzianum VTT-D-80150 concentrated culture filtrates as well as the purified siderophore inhibited the growth of the indicator yeasts. T. harzianum CBS 243.71 siderophore inhibited the growth of brown-rot fungi.

The extracellular ß-1,4-xylanase of the brown-rot fungus, Gloeophyllum trabeum, was isolated from crude extract by chromatofocusing method (PBE 94 column chromatography). The isoelectric point was estimated to 4.2-4.8 by cromatofocusing and 4.5 by isoelectric focusing (IEF). The molecular weight of the enzyme was estimated to 37,000 dalton by SDS-PAGE. The optimal temperature for the crude extract xylanase was +70°C. The enzyme stability, after 1 h incubation, decreased sharply above +60°C and pH 6.