Food waste valorization through the production of polyhydroxyalkanoates by mixed microbial cultures

Dissertação para obtenção do Grau de Mestre em Engenharia Química e BioquímicaPolyhydroxyalkanoates (PHAs) are polyesters of hydroxyl fatty acids, which are accumulated in microbial cells as carbon/energy reserves. PHAs are bio-based and biodegradable and display a wide range of thermoplastic properties, being a promising alternative to conventional plastics. Presently, industrial PHA production was primarily based on pure microbial cultures. Although this process has high PHA production efficiency, it presents high costs associated with the use of chemically-defined feedstocks, and to the need for sterility. An attractive feature of mixed microbial cultures (MMCs) PHAs production is the ability to use waste/surplus feedstocks. Many industrial wastes are seasonally produced making it necessary find the best method of utilization of this feedstock on PHA production process. Two different approaches might be taken account: (1) stock of industrial wastes during their production for their use throughout the year. However, the high fermentability of these agro-industrial wastes makes them susceptible to degradation during storage period; (2) the use of different feedstocks over the year according its availability. It is thus important to study MMC’s response to different feedstocks. The aim of this work is study how MMC PHA production process is affected by a feedstock shift, using cheese whey (CW) and sugar cane molasses (SCM) as model feedstocks. The use of waste based feedstock by MMCs requires a previous conversion of sugars to organic acids (OAs), which is achieved through anaerobic fermentation. In this study, a three-stage MMC PHA process was used, comprising: (1) anaerobic fermentation of surplus feedstocks to produce OAs in a membrane bioreactor (AnMBR); (2) PHA accumulating culture selection in a sequencing batch reactor (SBR) under feast and famine conditions using fermented feedstocks; and (3) PHA production using the selected cultures and the OAs produced in the earlier stages. Initially the effect of both feedstocks (CW and, SCM) in the acidogenic fermentation (stage 1) was assessed. Firstly, the AnMBR was operated under steady state with CW. When the feedstock was changed to SCM an adaption period of about 10 to 15 days was observed. When SCM was replaced by CW a faster adaptation response, approximately 7 days, was observed. The AnMBR reached similar OAs profiles in both phases when CW was fed (% g-COD HAA/g-COD OAs): 65% acetate, 10% propionate, 22% butyrate, 2% valerate, and 1% lactate. These results demonstrate that the system’s performance is reproducible. On the other hand, the anaerobic fermentation of a different feedstock, SCM, resulted in a different OAs profile (%g-COD HAA/g-COD OAs): 24% acetate, 38% propionate, 19% butyrate, and 19% valerate. In a second phase, different fermented feedstocks were used in the selection of PHA-storing organisms under a feast and famine regime in a SBR (stage 2). Initially the SBR was fed with a synthetic OAs solution; then fermented SCM (fSCM) and fermented CW (fCW) were subsequently fed as they were produced in the AnMBR. The adaption of the MMC to fSCM was faster than the adaptation to fCW. Whenever steady state was reached, PHA accumulation tests were performed using the enriched MMC fed with the corresponding feedstock (stage 3), namely synthetic OAs solution, fSCM, and fCW. Storage yields of 0.74, 0.49, and 0.73 C-mol PHA/ C-mol OAs were obtained with synthetic OAs solution, fermented molasses, and fermented CW, respectively. The culture reached a maximum PHA content of 60%, 56% and 65%, when feedstock fed were synthetic OAs solution, fSCM and fCW, respectively. A direct relation between the used feedstock and the polymers composition was observed, which was related with the different OAs profile. Even though, the shift of complex feedstock in three-stage MMC PHA process is still at a very early stage of development, this work illustrates the advantage of favoring the selection of cultures with the capacity to adapt its metabolism to different feedstocks. This will offer the possibility of using numerous substrates and improving strategies to optimize acidogenic fermentation, culture selection and polymer production

Integrated reporting an exploratory study on the motivations and obstacles in the adoption of a new information reporting system

This study explores the motives for voluntary adoption and reasons for non-adoption of integrated reporting by Portuguese listed companies. For this purpose, a questionnaire survey was addressed to adopters and non-adopters of integrated reporting. The results reveal motivations for integrated reporting associated with external pressures and reporting trends of other companies. The cost of implementing this new reporting system seems to be the main reason why few companies do it yet. The preparation of sustainability information in accordance with internationally recognized frameworks seems to be the current priority of companies and an intermediate step between traditional financial reporting and integrated reporting.info:eu-repo/semantics/publishedVersio

Marketing experiencial e a sua influência no consumidor: o caso Nespresso

Nos dias de hoje, as experiências são consideradas um fator de diferenciação fundamental para as empresas dado que os produtos e serviços passaram a ser semelhantes no que diz respeito aos seus atributos funcionais. Além disso, cada vez mais as escolhas dos indivíduos são influenciadas não só por fatores racionais, mas principalmente por fatores emocionais. Assim, o presente estudo, inserido na área do marketing experiencial, tenciona compreender se as dimensões da experiência influenciam a satisfação e a lealdade dos consumidores. Por fim, analisar se a satisfação tem influência na lealdade do consumidor. Para o efeito, o estudo focou-se na marca Nespresso, e foi aplicado um inquérito "online" de forma a averiguar as hipóteses previamente estabelecidas. Tendo em consideração os objetivos do estudo, era necessário que os inquiridos conhecessem e adquirissem produtos da marca Nespresso. Assim, foram consideradas válidas 153 das 212 respostas obtidas. A análise das hipóteses foi realizada através do Coeficiente de Correlação de Pearson, que indicou uma associação positiva entre as variáveis, e com recurso à regressão linear que permitiu avaliar a influência das variáveis umas nas outras. Os resultados das regressões lineares indicaram que das 9 hipóteses, apenas 5 foram comprovadas através do presente estudo. As conclusões do estudo indicam que, das várias dimensões da experiência da marca, apenas a dimensão sensorial e a dimensão afetiva têm uma influência positiva na satisfação do consumidor e somente a dimensão afetiva e comportamental têm influência na lealdade à marca. Por fim, comprovou-se que a satisfação afeta positivamente a lealdade.Nowadays, the experiences are considered a fundamental differentiation factor for companies since most products and services became similar in their functional attributes. More and more individuals' choices are influenced not only by rational factors, but also by emotional factors. Thus, this study, inserted in the area of experiential marketing, intends to understand if the dimensions of experience affect the satisfaction and consumers loyalty. Finally, to analyze if satisfaction has influence on consumer loyalty. To this end, the study focused on the Nespresso brand, and an online survey was applied in order to ascertain the previously established hypotheses. Given the study's objectives, it was necessary for respondents to know and have already acquired products of the Nespresso brand. Thus, 153 out of 212 total responses were considered valid. The analysis of the hypotheses was carried out through Pearson's Correlation Coefficient, which indicated a positive association between the variables, and using linear regression which allowed to evaluate the influence of the variables on each other. The results of the linear regressions indicated that of the 9 hypotheses previously established, only 5 were proved through this study. The conclusions of the study indicate that, of the several dimensions of the brand experience, only the sensorial dimension and the affective dimension have a positive influence on the consumer's satisfaction and only the affective and behavioral dimension have an influence on brand loyalty. Finally, it was proved that satisfaction positively affects loyalty

Rehabilitation of renders of old buildings in Portugal: survey, supporting methodology proposal and case study

The main purpose of the research is to present a proposal for a methodology to support the rehabilitation project of renders of old buildings in Portugal. To achieve the objective it was considered essential to define the main types of participants and aspects to integrate the proposal. The research methodology consists in an inquiry presented to professional participants in rehabilitation, a market study of materials and products available in Portugal, the design of a methodology proposal and its application to a case study. The inquiry sample totals 24 answers from the targeted professionals. A sequence of relevant supporting procedures consists in the proposal, which aims to provide a supporting methodology to decide and project in this context and also to be tested with its application to the building. This proposal was applied to an old building with load-bearing stone masonry walls and air-lime based renders. It was concluded that the assessment of the building and external renderings’ condition, its diagnosis and of the supporting walls, the definition of intervention, the specification of materials to be used and performance requirements to comply, and also plans for conservation and periodic maintenance, are crucial. From the inquiry, compatibility between materials and complementary roles and points of view of different types of participants in rehabilitation must be highlighted. A proposal for a methodology to support the project could provide useful guidance particularly for architects and construction engineers, and improve the understanding of direct participants on site, therefore contributing for the correct implementation of intervention

Percepção de crescimento pós-traumático e escrita expressiva : estudo exploratório com profissionais de uma instituição de acolhimento de crianças

Tese de mestrado, Psicologia (Secção Clínica e da Saúde - Núcleo de Psicoterapia Cognitivo-Comportamental Integrativa), Universidade de Lisboa, Faculdade de Psicologia, 2011Os efeitos físicos e psicológicos a longo-prazo que ocorrem em vítimas de um trauma têm sido vastamente estudados ao longo de décadas. Alguns estudos têm demonstrado que, para além dos efeitos negativos, também existem efeitos psicológicos positivos após um trauma. Neste estudo, pretendemos explorar a possibilidade de os mesmos efeitos poderem ser encontrados em indivíduos que, devido às características do seu trabalho, vivem diariamente o sofrimento de forma vicariante, não tendo necessariamente passado por um trauma de forma directa. Serão avaliados os efeitos psicológicos da exposição prolongada ao sofrimento usando, para isso, as teorias conhecidas sobre o Crescimento Pós-Traumático, através da análise dos principais desafios emocionais associados à profissão dos participantes, das estratégias de coping desenvolvidas ao longo do tempo para lidar com esses desafios e das mudanças pessoais e interpessoais que os participantes identificaram ao analisar a sua vida em termos retrospectivos. Foi pedido aos participantes que realizassem um exercício de escrita expressiva no qual se deveriam referir às emoções que sentem no seu trabalho e, na semana seguinte, foram conduzidas entrevistas individuais orientadas por um guião construído especificamente para o efeito. Nos resultados obtidos, tornou-se evidente que a exposição contínua e vicariante ao trauma é promotora de crescimento pessoal, no sentido em que os participantes revelaram mudanças significativas nas suas vidas que atribuem às aprendizagens possibilitadas pelo contexto profissional em que se inserem. É também demonstrado que os exercícios realizados por escrito antes das entrevistas contribuíram para que os participantes reflectissem sobre a sua vida de forma profunda, avaliando a sua própria evolução numa perspectiva longitudinal.Both physical and psychological long-term effects on trauma victims have been widely investigated worldwide. Some studies have shown that, in addition to the well-known negative effects of trauma, some positive psychological effects can be found as well. In this study, we will argue that the same effects can be found on individuals that, due to their day-to-day work, encounter severe suffering on others, even though they haven’t been through a trauma themselves. We will assess the psychological effects of such individuals based on the theories known today about post-traumatic growth, focusing on the emotional challenges associated with the participants’ line of work, the coping strategies they developed over time and the personal and interpersonal changes they identified on their lives. Participants were asked to do an expressive writing exercise about the emotions they experience at work and, in the following week, individual guided interviews took place. In our results, we will show that the prolonged exposure to other peoples’ traumas can promote personal growth, seeing that the participants showed several changes that they made to their lives after realizing how much they’ve learned from their professional experience. We will also show that the written exercises prior to the interviews were responsible for the participants’ better ability to think about themselves and to recall emotional experiences from the past