Organics recycling is increasing in New England as multiple states have enacted laws to divert organic materials, including food scraps and food processing residuals, away from landfills. Anaerobic digesters on dairy farms represent an attractive approach to food waste recycling because existing infrastructure is in place and co-digestion of dairy manure with food waste can increase renewable biogas production. In addition, anaerobic digestion results in effluents that can be separated into solid and liquid residual materials, or 'digestates'. Screw-press separated solids consist of lignocellulosic biomass resistant to microbial degradation during anaerobic digestion. These separated solids are typically recycled on farms as animal bedding before returning to the digester, whereas remaining liquid digestates are typically spread as fertilizer for nearby feed crops or pasture fields. Within this model, anaerobic digestion is not a nutrient management solution and repeated land application of digestate nutrients can create eutrophication risk over time. Alternative models are needed where digestate materials are converted into valuable products to be sold off-farm, enabling the removal of nutrients to help meet nutrient management goals. In this thesis, I address two research questions related to the pursuit of such alternative models. First, how do physicochemical characteristics of digestate materials vary across full-scale systems in the region, including systems with and without food waste as a substantial proportion of feedstock, and how do these variations affect the potential for conversion of digestates into valuable products (e.g., soil amendments)? Second, can separated digestate solids be used for commercial cultivation of gourmet oyster mushrooms (Pleurotus ostreatus) to produce food for human consumption, providing synchronous nutrient recovery and food production? Results from my first research chapter indicate that increasing food waste inputs (and thus diversification of feedstock recipes) will likely increase the variability of some solid and liquid digestate characteristics and can result in greater contamination with synthetic particles, with implications for nutrient recovery efforts and associated products. My second research chapter shows that screw-press separated digestate solids can offset non-local substrate ingredients to a degree while achieving oyster mushroom yields comparable to commercial recipes. Furthermore, this strategy could divert nutrients away from land adjacent to digesters and directly into safe, nutritious, protein-rich food for humans, while also producing a useful spent mushroom substrate product.

As microalgas são fontes sustentáveis de bioprodutos com alto valor agregado, que podem ser utilizados para diversos fins, tais como alimento, matéria-prima e energia. Devido a isso, as microalgas se condicionam como uma solução para suprir o aumento da população mundial, com a vantagem de serem obtidas sem uso de energia fóssil e terras agricultáveis. Entretanto, os custos associados à produção de microalgas ainda é muito alto, o que inviabiliza o seu uso em grande escala. A combinação do tratamento de esgoto e o crescimento de microalgas é uma promissora alternativa para reduzir os custos relacionados ao cultivo. No entanto, o esgoto afluente das ETEs brasileiras são altamente diluídos, o que torna o seu uso impraticável do ponto de vista técnico e econômico para o cultivo de microalgas. Nesse contexto, o presente trabalho propõe uma mistura de esgoto (esgoto sanitário e de suinocultura), visando aumentar a concentração de nutrientes (carbono, nitrogênio e fósforo), para o cultivo de Chlorella sorokiniana. Os resultados são promissores, com produção média de 1 g.L-1 de C. sorokiniana e remoção média de carbono inorgânico dissolvido (CID), ortofosfato (PO43-) e amônia (NH3) de 46 a 56%, 40 a 60% e 100%, respectivamente. Foi verificado que a remoção de NH3 por air stripping durante o cultivo afetou negativamente a produtividade de biomassa e remoção de nutrientes. Além disso, algumas propostas de separação foram estudadas, uma vez que essa etapa pode representar de 20 a 60% dos custos totais de produção de microalga. A alteração de pH seguida pela FAD apresentou altas eficiências (96,5 a 97,9%) nos pH de 12 a 13. A coagulação seguida pela FAD foi estudada utilizando coagulantes orgânicos e inorgânicos. As melhores doses foram de 10 mg·L-1 Zetag 8185; 75 mg·L-1 Tanfloc SG; 500 mg·L-1 Al2(SO4)3 e 1000 mg·L-1 FeCl3 que apresentaram uma eficiência máxima de 98,4; 94,5; 95,4; 96,7%; respectivamente. A sedimentação pela floculação alcalina com precipitados de fosfato de cálcio é eficiente, porém pode ser sensível à presença de compostos proteicos presentes no esgoto (albumina e matéria orgânica bacteriana). Entretanto, foram encontradas condições (pH 8 e 10) e concentrações (10 mg·L-1), nas quais a floculação alcalina foi efetiva. / Microalgae are sustainable sources of high-value bioproducts that can be used for a variety of purposes, such as food, raw materials and energy. For this reason, the microalgae are conditioned as a solution to supply the increase of the world population, with the advantage of being obtained without using fossil energy and arable land. However, the costs associated with the production of microalgae are still very high, which makes it impossible to use them in large-scale. The combination of wastewater treatment and microalgae cultivation is a viable option to reduce expenses related to cultivation. However, municipal wastewater from the centralized Brazilian sanitation system is highly diluted, and it is technically and economically impractical to use it for microalgae cultivation. In this context, the present work proposes a wastewater mixture (municipal and swine wastewater), aiming to increase the concentration of nutrients (carbon, nitrogen and phosphorus) for the cultivation of Chlorella sorokiniana. The results are promising, C. sorokiniana production reached around 1 g.L-1, with dissolved inorganic carbon (DIC), ortophosphate (PO43-) and ammonia (NH3) average removal from 46 to 56%, 40 to 60% and 100%, respectively. It was found that NH3 removal by air stripping during cultivation negatively affected the biomass productivity and nutrient removal. In addition, some harvesting method proposals have been studied, since this step represents 20 to 60% of the total costs of microalgae production. The pH modulation followed by DAF showed high efficiencies (96.5 to 97.9%) at pH 12 to 13. Coagulation followed by DAF was studied using organic and inorganic coagulants. The best doses were 10 mg·L-1 Zetag 8185; 75 mg·L-1 Tanfloc SG; 500 mg·L-1 Al2(SO4)3 and 1000 mg·L-1 FeCl3 which had a maximum efficiency of 98.4, 94.5, 95.4, 96.7%, respectively. Alkaline flocculation using calcium phosphate precipitates is an efficient harvesting method, but it can be sensitive to the presence of protein compounds in the wastewater (albumin and bacterial organic matter). However, it was found conditions (pH 8 e 10) and concentrations (10 mg·L-1) at which alkaline flocculation was effective.

No description available.

An investigation was made into the isolation and screening of highly cellulolytic anaerobic fungi and their production of cellulolytic enzymes using immobilised rhizomycelia. A total of 46 anaerobic fungi were isolated on cellulosic substrates from ruminant and non-ruminant herbivores. Primary screening of these isolates was performed using dye release from cellulose-azure which qualitatively detected cellulolytic activity. Twelve isolates were chosen on the basis of their maximum solubilisation rates of the labelled cellulose and then subjected to secondary screening which involved the quantification of enzyme activity. The enzyme mixtures were characterised by carboxymethylcellulase, xylanase, B-glucosidase, B-xylosidase and cellobiase assays, measured by the production of either reducing sugars, p-nitrophenol or glucose. All strains produced a number of enzymes that allowed them to hydrolyse straw and highest enzyme activity was measured in static cultures grown on 0.5% straw. A monocentric isolate, Piromyces strain KSX1 from a red kangaroo, and a cattle polycentric isolate, Orpinomyces strain 478P1, were selected for study of cellulolytic enzyme production on the basis of high fibre digestion capability and amenability toward encapsulation. The immobilised polycentric strain proved to be operationally superior to strain KSX1 as strain 478P1 did not produce any viable growth in the culture liquor. Studies into single batch cultures of free cells of strains KSX1 and 478P1 revealed that the maximum specific rate of B-glucosidase production occurred concomitantly with maximum specific growth rate suggesting that the immobilised fungus must grow for continuous enzyme production to occur. Although the physiology of cellulase synthesis in strains KSX1 and 478P1 was found to be growth-associated, immobilisation of the fungus offered the advantage of the repeat-batch use of cells with the accumulation of extracellular enzymes after each batch. Thus, operational gains were the key issues in assessing the potential application of immobilised anaerobic fungi in the production of cellulolytic enzymes. The repeat-batch system was operationally more efficient than the free cell batch cultures because immobilisation removed the need of reculturing the cells for every single batch. / Doctor of Philosophy (PhD)

<p>The United States of America is one of the most powerful countries in the world and their broadcasting system has become a role model to the rest of the world. Since the US charge less for their media products in third world countries, it is cheaper even for poor countries to import American content than to purchase local products. The aim with our survey is to explore whether heavy consumers of American television programs in Kenya hold positive attitudes to the American lifestyle and experience feelings of relative deprivation as a result of this consumption. Comparisons are made between students in an urban and a rural area.</p><p>The theoretical framework for this study includes cultivation theory which investigates the effects of the values and behaviors of the television audience. It also includes relative deprivation, which is based on the assumption that people experience deprivation when they compare themselves with others – so called reference groups. In our case the reference group is the American lifestyle. A third theory used for this study is cultural imperialism which says that dominating, mainly western media corporations impose their cultural values on third world countries, as in this case, Kenya.</p><p>In this study we are using a quantitative survey based on questionnaires handed out to Kenyan students at two different universities, one in a rural and one in an urban part of Kenya.</p><p>Television is an important part of everyday life for Kenyan students and they consume more than we had predicted. We concluded that the respondents in our study generally have negative attitudes to their life and their country, but a more positive impression of life in the US. Relating these findings to the television consumption of the respondents, the students that watch American programs the most are students at the university in the urban area, and they are more positively disposed to Kenya, but more negative to the US, compared to the Egerton students in the rural area that generally do not favor American programs. These results do not support the theories chosen for this study. Based on our results, our conclusion is that the attitudes held by the USIU students do not originate from television consumption, but do most likely depend on other influences.</p>

The Bureau of Land Managements (BLM) Emergency Fire Rehabilitation (EFR) policy was developed in 1985 to encourage protection of sites from soil erosion and to minimize potential changes in vegetation communities that may result from the dominance of weedy species. To achieve the goals of EFR policy, managers often used introduced perennial grasses that established quicker and competed better with introduced annuals than did native plants. However, the change of sagebrush-grass communities to communities dominated by introduced forage grasses has led to concerns for wildlife habitat. This concern contributed to a policy change encouraging the use of native species, when available, for rehabilitation projects. This study attempts to assess the effectiveness of BLM EFR projects in meeting the stated goals of the BLM EFR policy in the Great Basin. To do this, two field offices per state were randomly selected from an inclusive list of all Great Basin field offices. In 2001, we randomly selected three EFR projects per field office from those projects that used native species. On each project site, we used a common monitoring technique in association with monitoring techniques implemented by the BLM to assess if national EFR objectives were being met. A semi-structured survey was developed to determine the potential reasons why native and introduced plants were either used or not used, why monitoring was and was not proposed, and whether monitoring was implemented in rehabilitation projects. BLM monitoring techniques did not adequately evaluate EFR goal achievement. The time it took to implement any of the BLM methods did not differ significantly from the time needed to implement the common protocol on the two projects where BLM had implemented monitoring and used native plants (F[subscript 3,12]=1.63, P=0.23). Cost to implement the common monitoring technique was minimal and it directly measured aspects of stated EFR policy goals. Vegetative cover of all natives, seeded and volunteers, contributed half of the overall cover on EFR projects and was significantly higher than sown introduced species. Invasive species were intermediate and did not differ significantly from either the natives or the introduced. The seeded species were a subset of the native or introduced classes. Composition by cover between sown native, sown introduced, and invasive species did not differ significantly. Vegetation cover increased the surface soil stability 39% of the time and subsurface stability 56% beneath the vegetation. Respondents of the survey stated that they generally use more natives and more complex seed mixtures than they did historically. Many also stated that they prefer to use native over introduced species. However, most felt that introduced species are more effective in meeting EFR goals on the degraded sites than native species. All respondents would like to access a summarized report of other rehabilitation projects. The respondents were split between accessing it through the World Wide Web or through a written report. We believe that a common database could be created and maintained on the World Wide Web if a common sampling protocol was implemented. / Graduation date: 2004

Rickettsiae are obligate intracellular gram-negative bacteria transmitted by arthropod vectors. Rickettsiae sometimes cause disease in humans, typically with high fever, headache and occasionally an eschar. In Sweden, Rickettsia helvetica, belonging to the spotted fever group, is the only tick-transmitted rickettsia found free in nature. The pathogenic roll of R. helvetica has not been fully investigated, but it has been implicated in aneruptive fever and cardiac disease. This thesis describes parts of the transmission pathways of rickettsiae in Sweden. Rickettsia infection rates in ticks collected from birds were analysed, and the birds’ role as disseminators and reservoirs was studied. We found that more than one in ten ticks was infected with rickettsia bacteria, predominantly R. helvetica, and that migrating birds contribute not only to long-distance dispersion of bacteria, but also to an inflow of novel and potentially pathogenic rickettsia species, in this case R. monacensis and R. sp. strain Davousti-like species, into Sweden. Further, wild and domestic animals were found to have seroreactivity against R. helvetica, which shows that they are exposed and susceptible to rickettsia. Their role as reservoirs has not been determined, yet they may indirectly be involved in transmission of rickettsia to humans by infected ticks feeding on them. The seroreactivity in humans was also studied. Patients investigated for suspected Borrelioses and blood donors had detectable antibodies against Rickettsia spp., with the highest prevalence detected in the suspected Borreliosis group. This shows that humans in Sweden are exposed to and develop an immune response against rickettsia. The suspicion that R. helvetica may cause severe symptoms was verified by a patient with subacute meningitis where the bacterium was shown for the first time to cause an invasive infection with CNS involvement and where the bacterium was isolated from the patient’s cerebrospinal fluid. Growth characteristics and morphology of R. helvetica were studied to better understand invasiveness and virulence. The findings indicate that the invasiveness is comparable with other rickettsia, though R. helvetica seems to have a stable but slightly slower growth.  Rickettsia helvetica is endemic in Sweden and therefore needs to be considered when investigating disease after a tick bite. / Rickettsia är en liten, strikt intracellulär, gramnegativ bakterie som sprids med vektorer som fästingar, löss och loppor. Bakterien kan orsaka Rickettsios hos människa, en sjukdom där de vanligaste symtomen är hög feber, huvudvärk, muskelvärk och i vissa fall ett bettmärke (eschar). I Sverige är Rickettsia helvetica, som tillhör spotted fever gruppen (SFG), den enda fästingöverförda rickettsia bakterien som hittats allmänt i naturen. Patogeniciteten för R. helvetica är ofullständigt utredd, men ”aneruptive fever” och hjärtmuskelinflammation har rapporterats. Avhandlingen beskriver delar av smittkedjan för SFG rickettsia i Sverige. Bakteriernas förekomst i fästingar plockade från fåglar har studerats, likaså det ekologiska tryck som flyttfåglars bärarskap av infekterade fästingar bidrar med när de korsar olika världsdelar. Mer än var tionde fästing var infekterad med rickettsia bakterier, i huvudsak R. helvetica. Det visade sig att flyttfåglar bidrar inte bara till långväga spridning av bakterier utan även till införsel av nya potentiellt patogena rickettsiaarter, i detta fall identifierades R. monacensis och en R. sp strain Davousti liknande art. Vidare analyserades seroreaktivitet mot Rickettsia helvetica hos både tamdjur och vilda djur, vilket visade på antikroppsutveckling, som uttryck för smittexposition, i mer än vart femte djur. Djurens roll som reservoar för bakterien är inte klarlagd, men oavsett är djuren indirekt involverade i spridningen av bakterien till människa via infekterade fästingar som suger blod. Seroreaktivitet hos människa har också studerats. Patienter, provtagna på grund av misstanke om borreliainfektion, samt blodgivare hade detekterbara antikroppar mot Rickettsiae, med högst prevalens i gruppen med misstänkt borreliainfektion. Fynden visar att människor i Sverige är exponerade för och utvecklar en immunreaktion mot rickettsia. Att R. helvetica skulle kunna ge allvarlig sjukdom verifieras av ett patientfall med subakut meningit där bakterien för första gången visats ge invasiv infektion med påverkan på nervsystemet (CNS engagemang) och där bakterien isolerats från patientens ryggmärgsvätska.  Morfologi och tillväxtegenskaper för R. helvetica undersöktes för att bättre förstå bakteriens invasivitet och virulens. Fynden indikerar att invasiviteten är jämförbar med andra rickettsiaarter men R. helvetica verkar ha en stabil men något långsammare tillväxt. Rickettsia helvetica är endemisk i Sverige och måste tas i beaktande vid sjukdomsutredning efter ett fästingbett.

The United States of America is one of the most powerful countries in the world and their broadcasting system has become a role model to the rest of the world. Since the US charge less for their media products in third world countries, it is cheaper even for poor countries to import American content than to purchase local products. The aim with our survey is to explore whether heavy consumers of American television programs in Kenya hold positive attitudes to the American lifestyle and experience feelings of relative deprivation as a result of this consumption. Comparisons are made between students in an urban and a rural area. The theoretical framework for this study includes cultivation theory which investigates the effects of the values and behaviors of the television audience. It also includes relative deprivation, which is based on the assumption that people experience deprivation when they compare themselves with others – so called reference groups. In our case the reference group is the American lifestyle. A third theory used for this study is cultural imperialism which says that dominating, mainly western media corporations impose their cultural values on third world countries, as in this case, Kenya. In this study we are using a quantitative survey based on questionnaires handed out to Kenyan students at two different universities, one in a rural and one in an urban part of Kenya. Television is an important part of everyday life for Kenyan students and they consume more than we had predicted. We concluded that the respondents in our study generally have negative attitudes to their life and their country, but a more positive impression of life in the US. Relating these findings to the television consumption of the respondents, the students that watch American programs the most are students at the university in the urban area, and they are more positively disposed to Kenya, but more negative to the US, compared to the Egerton students in the rural area that generally do not favor American programs. These results do not support the theories chosen for this study. Based on our results, our conclusion is that the attitudes held by the USIU students do not originate from television consumption, but do most likely depend on other influences.

<p>The aim of this work was to investigate and determine central parameters that can be used to control and increase the solubility, quality and productivity of recombinant proteins. These central parameters should be applicable under the constraints of high-throughput protein production in <em>Escherichia coli.</em></p><p>The present investigation shows that alternative methods exist to improve solubility, quality and productivity of the recombinant protein. The hypothesis is that by reducing the synthesis rate of the recombinant protein, a higher quality protein should be produced. The feed rate of glucose can be used to decrease the synthesis rate of the recombinant protein.</p><p>The influence of feed rate on solubility and proteolysis was investigated using the <em>lac</em>UV5-promoter and two model proteins, Zb-MalE and Zb-MalE31. Zb-MalE31 is a mutated form of Zb-MalE that contains two different amino acids. These altered amino acids greatly affect the solubility of the protein. The soluble fraction is generally twice as high using Zb-MalE compared to Zb-MalE31. Using a low feed rate compared to high benefits the formation of the full-length soluble protein. Furthermore, by using a low feed rate, the proteolysis can be decreased. One other factor that influences the solubility is the amount of inducer used. An increase from 100 µM to 300 µM IPTG only results in more inclusion bodies being formed, the fraction of soluble protein is the same.</p><p>The quality aspect of protein production was investigated for a secreted version of Zb-MalE using two different feed rates of glucose and the maltose induced promoter P<em>malK</em>. It was shown that when the protein was secreted to the periplasm, the stringent response as well as the accumulation of acetic acid (even for high feed rates) was reduced. The stringent response and accumulation of acetic acid are factors that are known to affect the quality and quantity of recombinant proteins. Transporting the protein to the periplasm results in this case on a lower burden on the cell, which leads to less degradation products being formed when the protein is secreted to the periplasm.</p><p>Seeing the feed rate as a critical parameter, the high-throughput production would benefit from a variation in the feed rate. However, since the fed-batch technique is technically complicated for small volumes another approach is needed. <em>E.coli</em> strains that have been mutated to create an internal growth limitation that simulate fed-batch were cultivated in batch and were compared to the parent strain. It was shown that the growth rate and acetic acid formation was comparable to the parent strain in fed-batch. Furthermore it was shown that a higher cell mass was reached using one of the mutants when the cells were cultivated for as long time as possible. The higher cell mass can be used to reach a higher total productivity.</p>

Diss. Stockholm : Univ., 2004.