Micropollutant bioremoval in wastewater treatment systems: from microbial population structure to function

Dissertation presented to obtain the Ph.D degree in Biology

Understanding the microbial ecology and ecophysiology of enhanced biological phosphorus removal processes through metabolic modelling and experimental studies

Dissertation to obtain the degree of Master in Chemical and Biochemical Engineering

Constraint-based modelling of mixed microbial populations: Application to polyhydroxyalkanoates production

Dissertação para obtenção do Grau de Doutor em Engenharia Química e Bioquímica

Microbial contribution to biofuels production

Dissertação para obtenção do Grau de Doutor em Engenharia Química e Bioquímica

Beriberi epidemic within rural Muslin fishing communities in Guiné - Bissau

Beriberi, ou cardiopatia e polineuropatia ligada à deficiência de tiamina, foi, antigamente, um flagelo nas populações. Os mais notáveis surtos de beriberi ocorreram após o advento da moagem de massa de arroz, em várias zonas da Ásia, no final do século XIX. Com a descoberta de vitamina B1, "anti-beriberi", e, subsequentemente, o enriquecimento de alimentos e as campanhas de sensibilização de saúde pública, a doença foi esquecida por muitos profissionais de saúde. Contudo, sabe-se que, hoje em dia, em diferentes partes do mundo, muitos casos de beriberi são os focos primários de epidemias de outras deficiências potencialmentes fatais, em comunidades vulneráveis. Determinados alimentos, assim como o álcool, são conhecidos para reduzir a absorção de vitamina B1. A Encefalopatia de Wernicke, a deficiência de tiamina mais conhecida pelos médicos que trabalham em países desenvolvidos, está associada à ingestão de álcool. Estudos recentes demonstraram, por um lado, atrasos significativos do desenvolvimento neurolinguístico em crianças alimentadas com leite sem tiamina, assim como uma possível correlação entre malária grave e deficiencia em Vitamina B1, o que reforça a importância desta vitamina na saúde das populações. A Guiné-Bissau, um país fragilizado pelos conflitos coloniais e pós-coloniais, instabilidade política, tráfico de droga e deficiente acesso à Saúde, continua sendo um dos países mais pobres do mundo. A maioria da população vive da agricultura de subsistência, pesca e colheita de cajú. O Islão é practicado por quase metade da população, e as religiões animistas e cristãs compõem as outras religiões principais do país. De acordo com a fé islâmica, os muçulmanos da Guiné-Bissau praticam o jejum, em função da luz do dia, durante o mês de Ramadão. Existe pouca investigação publicada sobre os efeitos nutricionais e na saúde deste ritual. Este trabalho é o primeiro a relacionar uma deficiência de micronutrientes ao mês sagrado do Ramadão. Esta tese apresenta casos clínicos de beriberi em comunidades rurais muçulmanas, que ocorreram no final da época das chuvas, que coincide com o mês de Ramadão. A análise dos dados mostra que, uma vez que alguns dos doentes apresentavam os mesmos sintomas, repetidamente, todos os anos, estes casos podem refletir a ponta do iceberg da ocorrência de beriberi na Guiné-Bissau. Parte da discussão centra-se na necessidade de mais investigação para confirmar o grau de deficiência na população em geral, efeitos de deficiência de tiamina relacionados com a malária, e consequências possíveis da deficiência marginal, a longo prazo, desta vitamina na saúde. A discussão apresenta ainda sugestões práticas para a redução da incidência da deficiência de vitamina B1 na Guiné-Bissau.

Novel ready-to-eat mango product using gellan gum as gelling agent: physico-chemical, microbial and sensory characteristics

Este trabalho foi efectuado com o apoio da Universidade de Lisboa, Instituto Superior de Agronomia com o Centro de Engenharia dos Biossistemas (CEER

Identifying the urban communities of New York City using bikeshare data from NYC citibike

This study identifies a measure of the cultural importance of an area within a city. It does so by making use of origindestination trip data and the bike stations of the bike share system in New York City as a proxy to study the city. Rarely is movement in the city studied at such a small scale. The change in strength of the similarity of movement between each station is studied. It is the first study to provide this measure of importance for every point in the system. This measure is then related to the characteristics which make for vibrant city communities, namely highly mixed land use types. It reveals that the spatial pattern of important areas remains constant over differing time periods. Communities are then characterised by the land uses surrounding these stations with high measures of importance. Finally it identifies the areas of global cultural importance alongside the areas of local importance to the city.

Fungal communities in archives: assessment strategies and impact on paper conservation and human health

The main results presented in this PhD Dissertation have been published in interna-tional journals included in the Science Citation Index (SCI)

How much cultural events are "worth" for host communities: Case of Faz Música Lisboa

This paper studies the economic and social impact of Faz Música Lisboa on the segment of society that feels from any direct or indirect consequence due to its existence. A qualitative research based on surveys and interviews is made to retract a list of the benefits and costs that each stakeholder perceives. Relying on the quantifiable variables, it is performed a cost-benefit analysis to measure how much the event is “worth” for the community. I conclude this is a viable project, as it brings a positive net benefit to the society, value that could increase with a higher institutional support.

Impact of carbon/nitrogen feeding strategy on polyhydroxyalkanoates production using mixed microbial cultures

Polyhydroxyalkanoates (PHA) production using mixed microbial cultures (MMC) requires a multi-stage process involving the microbial selection of PHA-storing microorganisms, typically operated in sequencing batch reactors (SBR), and an accumulation reactor. Since low-cost renewable feedstocks used as process feedstock are often nitrogen-deficient, nutrient supply in the selection stage is required to allow for microbial growth. In this context, the possibility to uncouple nitrogen supply from carbon feeding within the SBR cycle has been investigated in this study. Moreover, three different COD:N ratios (100:3.79, 100:3.03 and 100:2.43) were tested in three different runs which also allowed the study of COD:N ratio on the SBR performance. For each run, a synthetic mixture of acetic and propionic acids at an overall organic load rate of 8.5 gCOD L-1 d-1 was used as carbon feedstock, whereas ammonium sulfate was the nitrogen source in a lab-scale sequence batch reactor (SBR) with 1 L of working volume. Besides, a sludge retention time (SRT) of 1 d was used as well as a 6 h cycle length. The uncoupled feeding strategy significantly enhanced the selective pressure towards PHA-storing microorganisms, resulting in a two-fold increase in the PHA production (up to about 1.3 gCOD L-1). A high storage response was observed for the two runs with the COD:N ratios (gCOD:gN) of 100:3.79 and 100:3.03, whereas the lowest investigated nitrogen load resulted in very poor performance in terms of polymer production. In fact, strong nitrogen limitation caused fungi to grow and a very poor storage ability by microorganisms that thrived in those conditions. The COD:N ratio also affected the polymer composition, indeed the produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) showed a variable HV content (1-20 %, w/w) among the three runs, lessening as the COD:N increased. This clearly suggests the possibility to use the COD:N ratio as a tool for tuning polymer properties regardless the composition of the feedstock.

Coupling organic substrate removal to methane production in a fully biological microbial electrolysis cell

Microbial electrolysis cells (MECs) are an innovative and emerging technique based on the use of solid-state electrodes to stimulate microbial metabolism for wastewater treatment and simultaneous production of value-added compounds (such as methane). This research studied the performance of a two-chamber MEC in terms of organic matter oxidation (at the anode) and methane production (at the cathode). MEC‟s anode had been previously inoculated with an activated sludge, whereas the cathode chamber inoculum was an anaerobic sludge (containing methanogenic microorganisms). During the experimentation, the bioanode was continuously fed with synthetic solutions in anaerobic basal medium, at an organic load rate (OLR) of around 1 g L-1 d-1, referred to the chemical oxygen demand (COD). At the beginning (Run I), the feeding solution contained acetate and subsequently (Run II) it was replaced with a more complex solution containing soluble organic compounds other than acetate. For both conditions, the anode potential was controlled at -0.1 V vs. standard hydrogen electrode, by means of a potentiostat. During Run I, over 80% of the influent acetate was anaerobically oxidized at the anode, and the resulting electric current was recovered as methane at the cathode (with a cathode capture efficiency, CCE, accounting around 115 %). The average energy efficiency of the system (i.e., the energy captured into methane relative to the electrical energy input) under these conditions was over 170%. However, reactor‟s performance decreased over time during this run. Throughout Run II, a substrate oxidation over 60% (on COD basis) was observed. The electric current produced (57% of coulombic efficiency) was also recovered as methane, with a CCE of 90%. For this run the MEC‟s average energy efficiency accounted for almost 170 %. During all the experimentation, a very low biomass growth was observed at the anode whereas ammonium was transferred through the cationic membrane and concentrated at the cathode. Tracer experiments and scanning electron microscopy analyses were also carried out to gain a deeper insight into the reactor performance and also to investigate the possible reasons for partial loss of performance. In conclusion, this research suggests the great potential of MEC to successfully treat low-strength wastewaters, with high energy efficiency and very low sludge production.