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Orientador: Sandra Maria Martins Franchetti / Banca: Marcos Roberto Monteiro / Banca: Eliana Aparecida de Rezende Duek / Banca: José Carlos Marconato / Banca: Derlene Attilli de Angelis / Resumo: Os plásticos vêm sendo cada vez mais utilizados em nosso cotidiano em diversos tipos de produtos, no entanto, esses materiais são muito persistentes no ambiente, o que aumenta a quantidade de resíduos plásticos depositados nos aterros sanitários. A mistura de polímeros buscando obter materiais com diferentes propriedades mecânicas e degradativas pode ser um caminho para facilitar a adesão microbiana na matriz polimérica e contribuir para alterar o tempo de degradação desses materiais em aterros sanitários. Este trabalho teve como objetivo investigar a biodegradação de filmes de blendas de PP/PCL obtidos por fusão e PVC/PCL, PVA/PCL e PVA/PVC obtidos por casting, utilizando microrganismos do solo e de chorume, através dos métodos de respirometria de Bartha, Espectroscopia de Absorção no infravermelho (FTIR), Calorimetria Exploratória Diferencial (DSC), Microscopia Eletrônica de Varredura (MEV), Medidas de ângulo de contato e Perda de massa. Os resultados mostraram que no solo, os filmes sofreram biodegradação oxidativa. Com a adição de chorume, ocorreu uma erosão superficial e diminuição da biodegradação, devido à mudança no sistema microbiano. A biodegradação em todos os filmes foi influenciada pela morfologia da matriz polimérica (principalmente a cristalinidade). O PVA favorece a biodegradação do PVC e o PVC inibe a degradação do PVA. Efeito semelhante ocorre com PVC/PCL. O PCL favorece a biodegradação do PVC na blenda e o PVC inibe a rápida biodegradação do PCL. A presença de grupos ésteres na matriz polimérica é fundamental para a ação microbiana, isto é, hidrólise enzimática dos mesmos. Um aumento de cristalinidade do polímero também é considerado um processo degradativo. / Abstract: Plastics are being increasingly used in our daily life in different types of products, however, these materials are very persistent in the environment, which increases the amount of plastic waste deposited in landfills. The mixture of polymers in different mechanical and degradative properties can be a way to facilitate the microbial adhesion in the polymeric matrix and help to modify the time of degradation of these materials in landfills. This work aims to investigate the biodegradation of films from blends of PP / PCL, obtained by melting and PVC / PCL, PVA / PCL and PVA / PVC, obtained by casting, using microorganisms soil and chorume, through methods of Bartha's respirometry, Spectroscopy infrared absorption (FTIR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), angle of contact and loss of weight. The results showed that in the soil, the films have undergone oxidative degradation. With the addition of chorume, there was a surface erosion and decreased degradation, due to the change in the microbial system. The degradation in all films was influenced by the morphology of the polymer matrix (mainly crystallinity). The degradation of PVA helps the blend (PVA/PVC) degradation and the PVC inhibits the degradation of the PVA in the blend. Similar effect occurs with PVC/PCL. PCL helps the degradation of PVC in the blend and PVC inhibits the degradation of the PCL. The esther group presence in polymer matrix is fundamental to allow the microbial action, i.e., enzymatic hydrolysis of these groups. Polymer crystallinity increase is considered a degradative process. / Doutor

The major phenolic lipids from natural and technical Cashew Nut-Shell Liquids were isolated by various techniques including precipitation, chemical purification, distillation, phase separation and chromatography. Cardanol, 3-pentadecyl phenol and cardol were polyethoxylated under base catalysed conditions and the products were characterised by both nmr and HPLC. Their surfactant properties were then analysed by surface tension measurements and their rates and extent of biodegradation were evaluated by means of a modified OECD screening test. The synthesis of the biosyntetic intermediate 2,4-dihydroxy-6-pentadecyl benzoic acid, by means of a Horner-Emmons modification to the Wittig reaction, is also reported. Some studies with cavitands are also reported, including the synthesis of some novel macrocycles and some sugar transport studies.

Lignin degradation under biosulphidogenic conditions has not been extensively reported in the literature. Although aerobic degradation of lignin is well documented, anaerobic biodegradation has focused mainly on methanogenic systems with biosulphidogenic systems receiving less attention. Sulphate reducing bacteria are known to generate moderately high levels of both sulphide and alkalinity at room temperatures, and these conditions draw some comparison with the Kraft pulping process. In the Kraft pulping process, lignin is degraded chemically at ±170°C under high sulphide and alkaline conditions and may provide a model for understanding biosulphidogenic lignin degrading activity. The aim of this study was to investigate the biosulphidogenic hydrolysis of lignin within the context of the chemical and biological conditions generated by a mixed sulphate reducing bacteria consortia. Bioreactor studies with a mixed sulphate reducing consortia and pine wood powder (both untreated and depectinated) resulted in the generation of comparable levels of sulphide and alkalinity used in the chemical hydrolysis studies. Aromatic compound yields were between 20 to 50% of the chemical hydrolysis studies. This fluctuation may have been due to the utilization of these aromatic compounds as electron donors by the sulphate reducing consortia as evidenced by the high rate of sulphate reduction in both the untreated and depectinated wood bioreactors. Biodegradation of lignin model compounds was investigated in order to elucidate lignin degradation mechanisms. Both mono-aromatic and dimeric lignin model compounds were used as electron donors and carbon sources for the mixed sulphate reducing consortia. Biodegradation and mass spectrometer analysis of mono-aromatic compounds, ferulic acid and ferulic acid ethyl ester resulted in the production of intermediates such as catechol, cyclohexane carboxylic acid and adipic acid. These intermediates were also observed in the degradation of dimeric ferulic acid. Biodegradation of salicin resulted in the production of salicyl alcohol, ortho-cresol and acetate. Biodegradation of benzylic ether resulted in the production of vanillin and acetate as end products. The results of these studies provide evidence for a biosulphidogenic hydrolysis of lignin, and also the utilisation of lignin-derived aromatic compounds as electron donor sources, by a mixed sulphate reducing consortia.

Rates of litter decomposition, nutrient release, and total forest floor turnover were measured on two replicates of three ecosystem types in the Coastal Western Hemlock Zone of British Columbia, in an attempt to establish whether or not ecosystem types could be differentiated on the basis of functional parameters. Litter bags of two mesh sizes and leaf tethering were used to compare weight losses and nutrient dynamics of specific litter components. The dry weight losses of conifer needles confined in 1 mm mesh bags ranged from 30 to 40 % after one year. There was no significant difference between sites, Weight loss of salal leaves on xeric sites ranged from 20 % after one year for samples confined in 1 mm mesh bags to 45 % for tethered leaf samples. Big-leaf maple weight loss ranged from 15% for samples confined in 1 mm mesh bags to 60 % for tethered samples. Twig samples lost 7 to 21 % of their weight on all sites after six months, with slightly higher values occurring on the hygric sites, Cellulose strips in 4 mm mesh bags lost an average of 23 % of their weight on the-xeric, 21 % on the mesic, and 40 % on the hygric sites. Nutrient mass and concentration changes over one year varied somewhat between different types of foliage litter. The total mass of K, Mg, and Ca decreased in all litter types on all sites, N and P mass changes were more variable, The relative mobility of nutrients released from decomposing conifer litter was Ca> Mg?P>K>N, and from broad-leaf litter was Ca>Mg>K>P>N. The low mobility of K was concluded to be due to leaching of this element from the litter prior to its collection for the study. Numbers of fauna in the forest floor were compared on one replicate of each of the ecosystem types at six week intervals throughout the year. Micro-fauna were more abundant on the xeric and mesic sites, while macro- and meso-fauna were more numerous on the hygric sites. Numbers were lowest on all sites when forest floor moisture was lowest in August. At other times of the year population fluctuations were different for different fauna groups. Forest floor biomass was also measured on one replicate of each ecosystem type. It averaged 45,05 tonnes • ha⁻¹ on the xeric sites, 45.68 tonnes • ha⁻¹ on the mesic sites, and 25,20 tonnes • ha⁻¹ on the hygric site. Annual forest floor turnover rates were calculated to be .015 for the xeric, ,017 for the-mesic, and ,040 for the hygric sates, Differences in turnover rates between sites were attributed more to differences in the quantities- of wood and herbaceous foliage on the three sites than to differences in the decomposition rates of individual substrates. / Forestry, Faculty of / Unknown

Dissolved organic nitrogen (DON) in water and wastewater is a major public concern. In drinking water treatment plants (WTP), DON and biodegradable DON (BDON) may form carcinogenic by-products during disinfection and might also serve as a nutrient for microbiological growth in distribution systems. BDON in treated wastewater can promote algal growth in receiving water bodies. Understanding biodegradability of DON is important to develop strategies and processes capable of minimizing DON impact on the wastewater effluent receiving water bodies and drinking water. WTPs are nutrient-poor oligotrophic systems that receive source water with DON of about ≤2 mg N/L. Wastewater treatment plants (WWTPs) are nutrient-rich eutrophic systems which receive raw wastewater with DON of ≥8 mg N/L. At WWTPs, sidestream deammonification is a highly eutrophic system employed to treat highly concentrated streams of DON (≥100 mg N/L) and ammonia (≥1,500 mg N/L) generated from filtrate from anaerobically digested sludge dewatering. DON characteristics including biodegradability for different trophic levels could differ. The main goal of this dissertation is to investigate biodegradability of DON in these oligotrophic and eutrophic systems. Three research tasks were performed. In the first task, a method to measure BDON in oligotrophic systems was developed and applied to determine the fate of BDON along four treatment stages of a WTP with ozonation prior to filtration. Optimum dose of inocula and incubation time were identified for the BDON measurement. The Moorhead WTP, Moorhead, MN on average removed 30% of DON and 68% of BDON. The second task involved investigating the role of four biological wastewater treatment processes in removing DON from eutrophic systems. Nitrification process biodegraded 70, 54, and 57% of DON in influent, primary effluent, and secondary effluent, respectively. Heterotrophic DON removal was less (1.7 to 38%) while denitrification and deammonification did not remove DON. For the third task, BDON biodegradability in highly eutrophic system was investigated using nitrifying sludge. About 45 to 90% of DON in sidestream effluent was biodegradable. Information from this dissertation provides a better understanding on DON and BDON fate through water and wastewater treatment processes representing different trophic levels. / District of Columbia Water and Sewer Authority (DC WASA) / Department of Civil and Environmental Engineering, North Dakota State University

The utilization of biodegradable polymers is critical for developing “cradle to cradle” mindset with ecological, social and economic consequences. Poly(hydroxy butyrate-co-valerate) (PHBV) shows significant potential for many applications with a polypropylene equivalent mechanical performance. However, it has limitations including high crystallinity, brittleness, small processing window, etc. which need to be overcome before converting them into useful products. Further the development of biodegradable strain sensing polymer sensors for structural health monitoring has been a growing need. In this dissertation I utilize carbon nanotubes as a self sensing dispersed nanofiller. The impact of its addition on PHBV and a blend of PHBV with poly(butylene adipate-co-terephthalate) (PBAT) polymer was examined. Nanocomposites and blends of PHBV, PBAT, and MWCNTs were prepared by melt-blending. The effect of MWCNTs on PHBV crystallinity, crystalline phase, quasi-static and dynamic mechanical property was studied concurrently with piezoresistive response. In PHBV/PBAT blends a rare phenomenon of melting point elevation by the addition of low melting point PBAT was observed. The blends of these two semicrystalline aliphatic and aromatic polyesters were investigated by using differential scanning calorimetry, small angle X-ray scattering, dynamic mechanical analysis, surface energy measurement by contact angle method, polarized optical and scanning electron microscopy, and rheology. The study revealed a transition of immiscible blend compositions to miscible blend compositions across the 0-100 composition range. PHBV10, 20, and 30 were determined to be miscible blends based on a single Tg and rheological properties. The inter-relation between stress, strain, morphological structure and piezoresistive response of MWCNT filled PHBV and PHBV/PBAT blend system was thoroughly investigated. The outcomes of piezoreistivity study indicated MWCNT filled PHBV and PHBV/PBAT blend system as a viable technology for structural health monitoring. Finally, the compostability of pure polymer, blend system, and MWCNT filled system was studied indicating that PBAT and CNT decreased the biodegradability of PHBV with CNT being a better contributor than PBAT.

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The increased use of alcohols as gasoline additives, and possible substitutes, has prompted the investigation of the fate of gasoline/alcohol mixtures in the environment. In situ bioremediation is one technique that can successfully be applied to remove ground water contaminants particularly in situations where the adsorptive capacity of the soil plays a major role. Frequently, enhanced in situ bioremediation techniques rely on indigenous microorganisms to degrade ground water contaminants; this technique may sometimes include the addition of acclimated bacteria. In this study, soil microcosms were constructed in order to simulate the conditions found in a saturated aerobic aquifer. The biodegradation potential of methanol, benzene, and m-xylene was investigated. Uncontaminated soil from the surface, 12, 16.5, and 18 foot depths was utilized to observe the differences in microbial responses throughout the soil profile. The biodegradation potential of the indigenous microbiota was determined and compared to that of benzene acclimated bacteria, for all the compounds in the mixture. To observe the impact that chemical and physical soil characteristics may have on microbial responses, soils from each depth were classified on the basis of their particle size, moisture content and pH. Substantial methanol, benzene, and m-xylene biodegradation by the indigenous microorganisms occurred in all subsurface soils. While methanol was readily biodegradable over concentrations ranging from about 80 mg/L to about 200 mg/L, benzene inhibited methanol biodegradation at about 125 mg/L in all soil depths. The addition of benzene acclimated bacteria considerably increased the biodegradation rates of all compounds in the mixture. Such increases in biodegradation rates may be attributed to the activities of both groups, the indigenous microorganisms and the benzene acclimated bacteria. The results obtained by this study suggest that biodegradation of methanol, benzene, and m-xylene can readily occur in a saturated aerobic subsurface environment. The physical and chemical properties of a ground water aquifer seem to have a marked effect on microbial responses, and consequently on the biodegradation potential of water contaminants. / Master of Science