A Arthrospira (Spirulina) platensis, cianobactéria fotoautotrófica, tem sido cultivada para a produção de biomassa, apresentando em sua constituição proteínas, ácidos graxos poliinsaturados, pigmentos, minerais, vitaminas e aminoácidos. O uso de fontes de nitrogênio de baixo custo, como o sulfato de amônio, pode contribuir para a viabilização da produção de A. platensis. Neste trabalho foram verificados a influência de diferentes intensidades luminosas e protocolos de alimentação utilizando o sulfato de amônio, em cultivos realizados com reatores tubulares por processo descontínuo alimentado. As variáveis dependentes selecionadas foram concentração celular máxima (Xm), produtividade em células (Px), fator de conversão de nitrogênio em células (YX/N), bem como teores de proteínas e lipídios da biomassa. Foram obtidos excelentes resultados em cultivos realizados aplicando-se um protocolo de alimentação de sulfato de amônio, considerando biomassa seca de A. platensis com teor de 7 % de nitrogênio, com valor médio de Xm igual a 11414 mg.L-1. Este protocolo de adição de sulfato de amônio com intensidade luminosa de 240 µmol fótons. m-2.s-1 levou à melhor combinação de obtenção de Xm e Px, com valores finais de 12200 mg.L-1 e 1686 mg.L-1.d-1, respectivamente. Adicionalmente, nesse protocolo de adição de sulfato de amônio, os valores de concentração celular máxima foram da mesma ordem de grandeza que aqueles onde se utilizou nitrato de sódio, evidenciando, assim, a possibilidade do uso do sulfato de amônio como uma fonte de nitrogênio alternativa para o cultivo da A. platensis. / Arthrospira (Spirulina) platensis, a photoautotrophic cyanobacterium, has been cultivated for the production of biomass, and it is constituted by proteins, polyunsaturated fatty acids, chlorophyll, minerals, vitamins and amino acids. The use of low cost nitrogen sources, such as ammonium sulphate can contribute to the A. platensis production viability. It was verified in this work the influence of different light intensities and nutrient feeding protocols in fed-batch cultures developed in tubular reactors, where ammonium sulphate was used as a nitrogen source. The dependent variables were the maximum cell concentration (Xm), cell productivity (Px), nitrogen-to-cell conversion factor (YX/N), as well as proteins and lipids contents of the biomass. Excellent results were obtained when ammonium sulphate protocols were studied, considering A. platensis dry-weight with nitrogen levels of 7%, obtaining an average value of Xm corresponding to 11414 mg L-1. It was also obtained with this protocol, with light intensity of 240 µmol photons. m-2.s-1, the best combination to high values of Xm and Px, corresponding to 12200 mg.L-1 e 1686 mg.L-1.d-1, respectively. Moreover, in this protocol of ammonium sulphate addition, it was obtained values of the maximum cell concentration as high as the ones obtained with sodium nitrate as nitrogen source. This fact highlighted the possibility of using this alternative nitrogen source for the A. platensis cultivation.

A Arthrospira (Spirulina) platensis, cianobactéria fotoautotrófica, tem sido cultivada para a produção de biomassa, apresentando em sua constituição proteínas, ácidos graxos poliinsaturados, pigmentos, minerais, vitaminas e aminoácidos. O uso de fontes de nitrogênio de baixo custo, como o sulfato de amônio, pode contribuir para a viabilização da produção de A. platensis. Neste trabalho foram verificados a influência de diferentes intensidades luminosas e protocolos de alimentação utilizando o sulfato de amônio, em cultivos realizados com reatores tubulares por processo descontínuo alimentado. As variáveis dependentes selecionadas foram concentração celular máxima (Xm), produtividade em células (Px), fator de conversão de nitrogênio em células (YX/N), bem como teores de proteínas e lipídios da biomassa. Foram obtidos excelentes resultados em cultivos realizados aplicando-se um protocolo de alimentação de sulfato de amônio, considerando biomassa seca de A. platensis com teor de 7 % de nitrogênio, com valor médio de Xm igual a 11414 mg.L-1. Este protocolo de adição de sulfato de amônio com intensidade luminosa de 240 µmol fótons. m-2.s-1 levou à melhor combinação de obtenção de Xm e Px, com valores finais de 12200 mg.L-1 e 1686 mg.L-1.d-1, respectivamente. Adicionalmente, nesse protocolo de adição de sulfato de amônio, os valores de concentração celular máxima foram da mesma ordem de grandeza que aqueles onde se utilizou nitrato de sódio, evidenciando, assim, a possibilidade do uso do sulfato de amônio como uma fonte de nitrogênio alternativa para o cultivo da A. platensis. / Arthrospira (Spirulina) platensis, a photoautotrophic cyanobacterium, has been cultivated for the production of biomass, and it is constituted by proteins, polyunsaturated fatty acids, chlorophyll, minerals, vitamins and amino acids. The use of low cost nitrogen sources, such as ammonium sulphate can contribute to the A. platensis production viability. It was verified in this work the influence of different light intensities and nutrient feeding protocols in fed-batch cultures developed in tubular reactors, where ammonium sulphate was used as a nitrogen source. The dependent variables were the maximum cell concentration (Xm), cell productivity (Px), nitrogen-to-cell conversion factor (YX/N), as well as proteins and lipids contents of the biomass. Excellent results were obtained when ammonium sulphate protocols were studied, considering A. platensis dry-weight with nitrogen levels of 7%, obtaining an average value of Xm corresponding to 11414 mg L-1. It was also obtained with this protocol, with light intensity of 240 µmol photons. m-2.s-1, the best combination to high values of Xm and Px, corresponding to 12200 mg.L-1 e 1686 mg.L-1.d-1, respectively. Moreover, in this protocol of ammonium sulphate addition, it was obtained values of the maximum cell concentration as high as the ones obtained with sodium nitrate as nitrogen source. This fact highlighted the possibility of using this alternative nitrogen source for the A. platensis cultivation.

A produção da cianobactéria Arthrospira (Spirulina) platensis é considerada de interesse nas indústrias de alimentos, farmacêuticas e químicas. Diferentes fontes de nitrogênio alternativas têm sido sugeridas na literatura para seu cultivo, incluindo uréia e sais de amônio, visando à diminuição no custo do meio de cultivo. A perda de amônia por degasificação ocorre quando utilizados tanques abertos, justificando dessa forma o uso da associação de fontes de nitrato e de amônia em fotobiorreatores fechados. O nitrato de amônio (NH4NO3) contorna estas condições, proporcionando ao cultivo uma fonte de nitrogênio prontamente assimilável (amônio) e outra de reserva (nitrato), no mesmo composto. Neste trabalho verificou-se, pelo uso de um planejamento fatorial 22 com configuração de estrela, a influência da intensidade luminosa (I) e da adição de diferentes concentrações de NH4NO3 (mM), no crescimento e composição da biomassa de A. platensis em cultivos realizados em fotobiorreator tubular por processo descontínuo alimentado, utilizando um tempo de 6 dias alimentação para a fonte de nitrogênio. Parâmetros cinéticos de crescimento, como concentração celular máxima (Xm), produtividade em células (PX) e o fator de conversão de nitrogênio em células (YX/N), bem como o teor de proteínas e lipídios na biomassa foram avaliados. Através do uso da regressão multivariável para a otimização das condições experimentais, foram obtidos valores de Xm e de PX correspondentes a 4710 mg L-1 e 478,9 mg L-1d-1, respectivamente, pelo emprego de I = 148 µmol fótons m-2 s-1 e a adição de 9,7 mM de NH4NO3. O maior valor de YX/N registrado foi 8,1 mg mg-1, sendo superior aos obtidos com nitrato de sódio (0,80 mg mg-1). Os teores de proteína e de lipídios alcançaram valores de até 63,2 e 17,3 %, respectivamente. O emprego de NH4NO3 conduziu à redução dos custos de produção, sendo gastos em média R$ 15,97 da fonte de nitrogênio por quilograma de células, valor inferior se comparado com outras fontes usadas no cultivo de A. platensis como NaNO3 (R$ 59,10 por quilograma de células). O uso do NH4NO3 em fotobiorreator tubular mostrou-se promissor para o cultivo de A. platensis, ao proporcionar um aumento na produção de biomassa e diminuir a perda de amônia por degasificação. / The production of the cyanobacterium Arthrospira (Spirulina) platensis is considered of interest to the food, pharmaceutical and chemical industries. Alternative nitrogen sources have been suggested in literature, including urea and ammonium salts, in order to reduce the cost of cultivation medium. Ammonia off-gassing occurs when open ponds are used, thus justifying the utilization of nitrate and ammonia sources association. Ammonium nitrate (NH4NO3) attend this condition, providing the cultivation with a nitrogen source readily assimilated (ammonium) and with one of reserve (nitrate), in the same molecule. In this work, it was verified, using a 22 factorial design with star configuration, the influence of light intensity (I) and the addition of different concentrations of NH4NO3 (mM) on the growth and biomass composition of S. platensis in cultures carried out in tubular photobioreactor by fed-batch process, using a 6-day feeding time of the nitrogen source. Kinetic growth parameters, such as maximum cell concentration (Xm), cell productivity (Px) and yield of nitrogen to biomass (YX/N), as well the biomass content of protein and lipids, were evaluated. Through the use of regression analysis for the optimization of experimental conditions, values of Xm and PX such as 4710 mg L-1 and 478.9 mg L-1d-1, respectively, were obtained by the use of I = 148 µmol photons m-2 s-1 and the addition of 9.7 mM of NH4NO3. The highest value of YX/N obtained was 8.1 mg mg-1, higher than that provided by the use of sodium nitrate (0.80 mg mg-1). The levels of protein and lipid achieved up to 63.2 and 17.3 %, respectively. The use of NH4NO3 led to the reduction of culture medium costs, in which R$ 15.97 (Real/Brazil) were spent on nitrogen source per kilogram of cells, value that is lower if compared to other common sources used for A. platensis growth, such as NaNO3 (R$ 59.10 per kilogram of cells, Real/Brazil). The use of NH4NO3 in tubular photobioreactor proved to be promising for the cultivation of A. platensis, leading to an increase in biomass production and diminishing the ammonia lost by off-gassing.

Microbial communities are key drivers of biogeochemical cycles and several important industrial processes rely on complex, undefined microbial ecosystems for production or conversion of substrates for example in wastewater treatment or anaerobic digestion plants. Despite their significance, such communities are often poorly defined, if at all. This project concerned previously undefined secondary microbial communities (SMCs) from photobioreactors culturing cyanobacterium Arthrospira platensis, known for producing high-value protein-pigment complex C-phycocyanin (C-PC). C-PC has a range of applications in the biochemical/pharmaceutical and food industries. Next-generation sequencing methods were applied to characterize the SMCs sampled over the course of various batch runs. The bioreactor exerted a strong selective pressure on the SMC, initially diverse and dynamic, succeeded by a stable and predictable SMC dominated by a few species. SMC stability and diversity correlated with reactor performance, especially proliferation and instability of the rare-abundance sub-population; dominant species ratios were likely less important. The substantially larger (compared to other species present) A. platensis filaments may represent a dynamic microenvironment in itself, and if so, constitutes a significant parameter when optimizing culture conditions. Denser and carefully pre-acclimated inocula reduce the ecological space available to undesirable taxa (e.g. pathogens) otherwise below detectable/significant limits. This has implications for other processes that rely on mixed cultures and may be a control strategy in manufacturing active pharmaceutical ingredients to cGMP standards. Molecular data was used to obtain several pure isolates which were characterized further. Strategies to optimize performance with respect to SMCs were explored and evaluated. A significant aspect of this CASE project was an industrial placement with Scottish Bioenergy. The placement involved set-up of a production facility and incremental scale-up of cultivation from 2 L to 1000 L reactors; development of a downstream processing protocol covering harvesting, pigment extraction and protein purification, and some formulation/stability testing. A very low-cost method is described for obtaining relatively high-purities of C-PC, broadly considered the most costly part of the entire production process.

Micro-organismos fotossintetizantes, incluído aqui o gênero Arthrospira, vêm sendo amplamente produzidos em larga escala em vários países, detendo um mercado que gera mais de 1 bilhão de dólares ao ano. A produção industrial utiliza grande volume de água com alta concentração salina para produzir milhares de toneladas de biomassa microalgal. É crescente a utilização de tratamento de águas por processo de separação por membranas, demonstrando ser uma técnica que gera água de ótima qualidade, de instalação compacta e de fácil automação. No presente trabalho, foi avaliada esta tecnologia para o reaproveitamento do meio de cultura em novos cultivos de micro-organismos fotossintetizantes, visando contribuir para a sustentabilidade deste processo produtivo. O efluente do cultivo de Arthrospira platensis oriundo de processo descontínuo em minitanques foi submetido a tratamento por membranas de filtração tangencial, incluindo microfiltração (MF) (porosidades de 0,65 µm e de 0,22 µm) e ultrafiltração (UF) (peso molecular de corte de 5.000 Da), em pressões transmembrana (TMP) de 22,5 a 90 kPa. Os processos de MF levaram a reduções médias de 53,9±1,3 % e 93,1±1,1 % de matéria orgânica natural (NOM) e pigmentos nos meios residuais, respectivamente. Com o uso de processos de UF, cujos meios foram previamente tratados por MF (0,22 µm e 22,5 kPa), as reduções médias de NOM e pigmentos foram de 57,2±0,5 % e 94,0±0,8 %, respectivamente. Os processos de MF com TMP de 22,5 kPa levaram a concentrações celulares máximas (Xm) equivalentes às obtidas com meio novo. O uso de membrana de 0,65 µm e TMP de 22,5 kPa levou a uma perda média de 2,9 %, 22,7 % e 16,4% dos nutrientes carbonato, fosfato e nitrato, respectivamente, mas a correção desses valores aos mesmos do meio padrão levou à obtenção dos mais altos valores de Xm (3586,6±80 mg L-1), produtividade em células (505,0±11,6 mg L-1 d-1) e fator de conversão de nitrogênio em células (29,6±0,7 mg mg-1). O teor protéico da biomassa foi estatisticamente igual ao da biomassa obtida de cultivo com meio padrão novo. Os dados deste trabalho evidenciam que processos de filtração por membrana são promissores para o reuso de meio de micro-organismos fotossintetizantes. / Photosynthetic microorganisms, including here the genus Arthrospira, have been produced worldwide in large scale, in a market which generates more than $ 1 billion a year. The industrial production uses huge volume of water with high salinity to produce thousands of tons of microalgal biomass. It is increasing the use of membrane separation process in water treatment, proving to be a technique that generates high quality water, compact and easy both installation and automation. In this study, it was evaluated this technology for the recycling of the culture medium to produce photosynthetic microorganisms, aiming to contribute to the sustainability of this production process. The effluent from Arthrospira platensis culture originating from batch process in laboratory-scale open raceway tanks was treated by tangential flow filtration with microfiltration (MF) (membrane pore size of 0.65 µm and 0.22 µm) and ultrafiltration (UF) (molecular weight cut-off of 5,000 Da), using transmembrane pressure (TMP) from 22.5 up to 90 kPa. MF processes led to average reductions of 53,9±1.3% and 93.1±1.1% of natural organic matter (NOM) and pigments in the exhausted media, respectively. With the use of UF process, whose media were pre-treated by MF (0.22 µm and 22.5 kPa), the average NOM and pigments reductions were 57.2±0.5% and 94.0±0.8%, respectively. The MF process with TMP of 22.5 kPa led to maximum cell concentrations (Xm) equivalent to those obtained with the new medium. The use of membrane of 0.65 µm under TMP of 22.5 kPa led to an average loss of 2.9%, 22.7% and 16.4% of the nutrients carbonate, phosphate and nitrate, respectively, but correcting the concentration of these nutrients to those values present in the standard medium led to obtain the highest Xm (3586.6±80 mg L-1), cell productivity (505.0±11.6 mg L-1 d-1) and nitrogen-to-cell conversion yield (29.6±0.7 cells mg mg-1). The protein content of this biomass was statistically equal to that one obtained from cultivation with standard new medium. Data from this study show that membrane filtration processes are promising for reuse media in cultivation of photosynthetic microorganisms.

Micro-organismos fotossintetizantes, incluído aqui o gênero Arthrospira, vêm sendo amplamente produzidos em larga escala em vários países, detendo um mercado que gera mais de 1 bilhão de dólares ao ano. A produção industrial utiliza grande volume de água com alta concentração salina para produzir milhares de toneladas de biomassa microalgal. É crescente a utilização de tratamento de águas por processo de separação por membranas, demonstrando ser uma técnica que gera água de ótima qualidade, de instalação compacta e de fácil automação. No presente trabalho, foi avaliada esta tecnologia para o reaproveitamento do meio de cultura em novos cultivos de micro-organismos fotossintetizantes, visando contribuir para a sustentabilidade deste processo produtivo. O efluente do cultivo de Arthrospira platensis oriundo de processo descontínuo em minitanques foi submetido a tratamento por membranas de filtração tangencial, incluindo microfiltração (MF) (porosidades de 0,65 µm e de 0,22 µm) e ultrafiltração (UF) (peso molecular de corte de 5.000 Da), em pressões transmembrana (TMP) de 22,5 a 90 kPa. Os processos de MF levaram a reduções médias de 53,9±1,3 % e 93,1±1,1 % de matéria orgânica natural (NOM) e pigmentos nos meios residuais, respectivamente. Com o uso de processos de UF, cujos meios foram previamente tratados por MF (0,22 µm e 22,5 kPa), as reduções médias de NOM e pigmentos foram de 57,2±0,5 % e 94,0±0,8 %, respectivamente. Os processos de MF com TMP de 22,5 kPa levaram a concentrações celulares máximas (Xm) equivalentes às obtidas com meio novo. O uso de membrana de 0,65 µm e TMP de 22,5 kPa levou a uma perda média de 2,9 %, 22,7 % e 16,4% dos nutrientes carbonato, fosfato e nitrato, respectivamente, mas a correção desses valores aos mesmos do meio padrão levou à obtenção dos mais altos valores de Xm (3586,6±80 mg L-1), produtividade em células (505,0±11,6 mg L-1 d-1) e fator de conversão de nitrogênio em células (29,6±0,7 mg mg-1). O teor protéico da biomassa foi estatisticamente igual ao da biomassa obtida de cultivo com meio padrão novo. Os dados deste trabalho evidenciam que processos de filtração por membrana são promissores para o reuso de meio de micro-organismos fotossintetizantes. / Photosynthetic microorganisms, including here the genus Arthrospira, have been produced worldwide in large scale, in a market which generates more than $ 1 billion a year. The industrial production uses huge volume of water with high salinity to produce thousands of tons of microalgal biomass. It is increasing the use of membrane separation process in water treatment, proving to be a technique that generates high quality water, compact and easy both installation and automation. In this study, it was evaluated this technology for the recycling of the culture medium to produce photosynthetic microorganisms, aiming to contribute to the sustainability of this production process. The effluent from Arthrospira platensis culture originating from batch process in laboratory-scale open raceway tanks was treated by tangential flow filtration with microfiltration (MF) (membrane pore size of 0.65 µm and 0.22 µm) and ultrafiltration (UF) (molecular weight cut-off of 5,000 Da), using transmembrane pressure (TMP) from 22.5 up to 90 kPa. MF processes led to average reductions of 53,9±1.3% and 93.1±1.1% of natural organic matter (NOM) and pigments in the exhausted media, respectively. With the use of UF process, whose media were pre-treated by MF (0.22 µm and 22.5 kPa), the average NOM and pigments reductions were 57.2±0.5% and 94.0±0.8%, respectively. The MF process with TMP of 22.5 kPa led to maximum cell concentrations (Xm) equivalent to those obtained with the new medium. The use of membrane of 0.65 µm under TMP of 22.5 kPa led to an average loss of 2.9%, 22.7% and 16.4% of the nutrients carbonate, phosphate and nitrate, respectively, but correcting the concentration of these nutrients to those values present in the standard medium led to obtain the highest Xm (3586.6±80 mg L-1), cell productivity (505.0±11.6 mg L-1 d-1) and nitrogen-to-cell conversion yield (29.6±0.7 cells mg mg-1). The protein content of this biomass was statistically equal to that one obtained from cultivation with standard new medium. Data from this study show that membrane filtration processes are promising for reuse media in cultivation of photosynthetic microorganisms.

Coal seams are commonly associated with poor quality water that requires treatment. Water treatment can be very expensive and can severely affect the profitability of mining projects. This study investigated the potential cultivation of Arthrospira maxima (Spirulina) in coal seam water to beneficiate coal seam water in order to effectively offset the water treatment cost. The study was conducted in Northern South Africa and formed part of a larger Coal Seam Water Beneficiation Project (CSWBP). The study consisted of laboratory based Flask Studies and outdoor High Rate Algal Pond Studies. The Flask Studies that were carried out in the on-site field laboratory, found that the coal seam water could provide a suitable medium for Spirulina cultivation. In addition, it was found that the optimal pH for the selected strain ranged between 9 - 10.5 and that the addition of excess iron, up to 100 times the concentration found in defined growth media such as Schlösser’s, to the culture media could enhance productivity. The High Rate Algal Pond Studies (HRAP) were carried out over a period of 18 months. The studies showed that the coal seam water at the CSWBP is a valuable resource that can reduce media costs by 50% without affecting productivity. In a study encompassing 334 days it was shown that heating the culture through plate heat exchangers would result in a significant increase in productivity and a heated productivity of 19.86 g/m2/day was recorded. An unheated productivity of 14.11 g/m2/day was recorded. Therefore, it was found that it would be economically feasible to beneficiate coal seam water found at the CSWBP through the cultivation of Arthrospira maxima (Spirulina). / Environmental Sciences / M. Sc. (Environmental Science)

Coal seams are commonly associated with poor quality water that requires treatment. Water treatment can be very expensive and can severely affect the profitability of mining projects. This study investigated the potential cultivation of Arthrospira maxima (Spirulina) in coal seam water to beneficiate coal seam water in order to effectively offset the water treatment cost. The study was conducted in Northern South Africa and formed part of a larger Coal Seam Water Beneficiation Project (CSWBP). The study consisted of laboratory based Flask Studies and outdoor High Rate Algal Pond Studies. The Flask Studies that were carried out in the on-site field laboratory, found that the coal seam water could provide a suitable medium for Spirulina cultivation. In addition, it was found that the optimal pH for the selected strain ranged between 9 - 10.5 and that the addition of excess iron, up to 100 times the concentration found in defined growth media such as Schlösser’s, to the culture media could enhance productivity. The High Rate Algal Pond Studies (HRAP) were carried out over a period of 18 months. The studies showed that the coal seam water at the CSWBP is a valuable resource that can reduce media costs by 50% without affecting productivity. In a study encompassing 334 days it was shown that heating the culture through plate heat exchangers would result in a significant increase in productivity and a heated productivity of 19.86 g/m2/day was recorded. An unheated productivity of 14.11 g/m2/day was recorded. Therefore, it was found that it would be economically feasible to beneficiate coal seam water found at the CSWBP through the cultivation of Arthrospira maxima (Spirulina). / Environmental Sciences / M. Sc. (Environmental Science)

Tesis por compendio / [ES] Las microalgas son organismos unicelulares fotosintéticos microscópicos que se encuentran en gran variedad de ambientes y son muy eficientes en la transformación de energía solar en biomasa. Los estudios realizados hasta el momento hacen referencia a posibles beneficios de la incorporación de microalgas en la dieta, por la mejora del sistema cardiovascular, las propiedades adelgazantes y energizantes, capacidad antioxidante, o la reducción del colesterol y los triglicéridos. La forma más habitual de consumir las microalgas es como suplemento dietético en forma de tabletas, cápsulas o polvo. La incorporación de biomasa de microalgas en productos tradicionales se ha enfrentado al reto de la aparición de colores verdes fuertes, así como su consistencia pulverulenta que puede afectar la textura y percepción del producto. Todos estos aspectos constituyen las principales áreas de mejora para conseguir un mayor grado de aceptación de productos con microalgas, y son la base del reto de este proyecto. El objetivo de la presente tesis doctoral fue el desarrollo de nuevos productos alimentarios incorporando las propiedades nutricionales de la biomasa de microalgas, incrementando o mejorando con ello, las propiedades nutricionales del alimento original. Para conseguir este objetivo se evaluaron a nivel fisicoquímico, reológico y textural, la incorporación de diferentes especies de microalgas (Arthrospira platensis (Spirulina), Chlorella vulgaris, Dunaliella salina y Nannochloropsis gaditana) en distintas matrices alimentarias (productos horneados, emulsiones y extrusionados). Por otra parte, se evaluó y caracterizó la incorporación de las microalgas utilizando diferentes tecnologías como la impresión 3D o la extrusión. Además de cómo afecta la incorporación de las microalgas a los productos obtenidos, se evaluaron los aspectos nutricionales de su incorporación, en cuanto al aporte de minerales y su biodisponibilidad. Las propiedades reológicas de las masas y emulsiones enriquecidas con microalgas (Spirulina, Chlorella y Dunaliella) indicaron que su comportamiento viscoelástico fue modificado y mejorado, mostrando características aptas para este tipo de productos. La adición de microalgas (Spirulina y Chlorella) a las masas utilizadas para la impresión 3D de galletas y snacks, permitió una mejor extrusión o impresión de éstas, obteniendo muestras impresas en 3D de forma cilíndrica, más precisas en cuanto a sus dimensiones con respecto a la estructura cilíndrica diseñada. Además, las muestras impresas presentaron mayor estabilidad y resistencia, antes y después del proceso de horneado comparadas con la muestra control. Para los productos horneados, tanto para las rosquilletas como los snacks impresos en 3D, la adición de microalgas (Spirulina y Chlorella) permitió mayor estabilidad en términos de textura. Ligeros cambios en los parámetros fisicoquímicos y de expansión se produjeron por la adición de Spirulina y Chlorella en los productos extrusionados. Además, los extrusionados enriquecidos con Nannochloropsis, mostraron parámetros similares a los de la muestra de control. Todos los productos presentaron colores luminosos y apariencias innovadoras y atractivas. En cuanto a los minerales, se observó un aumento de P, K, Ca, Na, Mg, Fe y Se con la adición de Spirulina y Chlorella, junto con el aumento de la concentración adicionada de microalgas. Siguiendo la normativa sobre etiquetado nutricional de los alimentos, el enriquecimiento con microalgas en rosquilletas se puede clasificar como un alimento "rico en hierro (Fe)". De igual forma, las rosquilletas y galletas enriquecidas con microalgas pueden considerarse un alimento "alto en selenio (Se)". Además, la incorporación de Spirulina y Chlorella en las formulaciones de galletas, permitió una mayor bioaccesibilidad del contenido de P, K, Ca, Mg, Fe, Zn y Se para la absorción en el cuerpo comparado con las muestras control. / [CAT] Les microalgues són organismes unicellulars fotosintètics microscòpics. Són molt eficients a l'hora de transformar l'energia solar en biomassa. Els estudis realitzats fins ara fan referència a possibles beneficis de la incorporació de microalgues en la dieta per produir una millora del sistema cardiovascular, per presentar propietats per aprimar i donar energia, per mostrar capacitat antioxidant o per afavorir una reducció del colesterol i els triglicèrids. La forma més habitual de consumir microalgues és com a suplement dietètic en forma de tauleta, càpsula o en pols. La incorporació de biomassa de microalgues en productes tradicionals s'ha afrontat al repte de l'aparició d'un color verd fosc i d'una consistència polsosa que pot afectar a la textura i, per tant, a la percepció del producte. Aquests aspectes constituïxen les principals àrees de millora per aconseguir un major grau d'acceptació de productes amb microalgues i són la base del repte d'aquest projecte. L'objectiu d'aquesta tesi doctoral és el desenvolupament de nous productes alimentaris que incorporen les propietats nutricionals de la biomassa de microalgues, de manera que s'incrementen o es milloren les propietats nutricionals de l'aliment original. Per aconseguir aquest objectiu s'avaluaren a escala fisicoquímica, reològica i de textura la incorporació de diferents espècies de microalgues (Arthrospira platensis (Spirulina), Chlorella vulgaris, Dunaliella salina i Nannochloropsis gaditana) en diferents matrius alimentàries (productes fornejats, emulsions i extrudits). D'altra banda, s'avaluà i caracteritzà la incorporació de les microalgues utilitzant diferents tecnologies com la impressió en 3D o l'extrusió. A banda de valorar com afecta la incorporació de microalgues als productes elaborats, s'avaluaren els aspectes nutricionals, pel que fa a l'aportació i biodisponibilitat de minerals. Les propietats reològiques de les masses i emulsions enriquides amb microalgues (Spirulina, Chlorella i Dunaliella) indicaren que el seu comportament viscoelàstic fou modificat i millorat, de tal manera que mostrà característiques aptes per aquest tipus de productes. L'addició de microalgues (Spirulina i Chlorella) en les masses utilitzades per a la impressió 3D de galetes i snacks permeté una millor impressió, ja que s'obtingueren mostres impreses de forma cilíndrica amb unes dimensions més precises respecte a l'estructura cilíndrica dissenyada. A més, les mostres impreses presentaren una major estabilitat i resistència abans i després del procés de fornejat en comparació amb la mostra control. Respecte als productes fornejats, l'addició de microalgues (Spirulina i Chlorella) a les rosquilletes i els snacks impresos en 3D permeté una major estabilitat en termes de textura. Lleugers canvis als paràmetres fisicoquímics i d'expansió es produïren per l'addició d'Spirulina i Chlorella en els productes extrudits. A més, els extrudits que foren enriquits amb Nannochloropsis mostraren paràmetres similars als de la mostra control. Tots els productes presentaren colors lluminosos i aparences innovadores i atractives. Pel que fa als minerals, s'observà un augment de P, K, Ca, Na, Mg, Fe i Se quan s'afegí Spirulina i Chlorella, directament relacionat amb l'augment de la concentració de microalgues. Seguint la normativa sobre etiquetatge nutricional dels aliments, l'enriquiment amb microalgues en rosquilletes ens permet classificar-les com a aliment "ric en ferro (Fe)". De la mateixa manera, les rosquilletes i galetes enriquides amb microalgues poden considerar-se un aliment "alt en seleni (Se)". A més a més, la incorporació de Spirulina i Chlorella en les formulacions de galetes, permeté una major bioaccessibiltat del contingut de P, K, Ca, Mg, Fe, Zn i Se comparat amb les mostres control. / [EN] Microalgae are microscopic unicellular and photosynthetic organisms that can be found in a wide variety of environments. These microorganisms are very efficient when transforming solar energy into biomass, due to their cellular structure, which is completely submerged in an aqueous medium, forming an adequate surface for the exchange of nutrients and gases. Microalgae compounds are now known to exhibit cardioprotective, immunomodulatory, anti-proliferative, anti-inflammatory, cognitive, neurobehavioral and antimicrobial properties, amongst others. Researchers have shown possible benefits of the incorporation of microalgae in the diet so far. The most common way to consume microalgae is as a dietary supplement in the form of tablets, capsules or powder. The incorporation of microalgae biomass in traditional products has faced the challenge of the appearance of strong green colours, as well as its powdery consistency that can affect the texture and perception of the product. All these aspects constitute the main areas for improvement the development of microalgae-based products, and they are the challenges faced of this project. The main objective of this PhD Thesis was the development of novel food products incorporating the nutritional properties of microalgae biomass, thereby increasing or improving the nutritional properties of the original food matrix. To achieve this goal, the effect of the addition of different species of microalgae (Arthrospira platensis (Spirulina), Chlorella vulgaris, Dunaliella salina and Nannochloropsis gaditana) on the physicochemical, rheological and textural properties of different food matrices (baked products, emulsions and extrudates) was evaluated. Furthermore, the effect of the incorporation of microalgae using different technologies such as 3D printing or extrusion to obtain food products was studied. In addition, how the incorporation of microalgae affects the nutritional aspects of the food products in terms of the contribution of minerals and their bioavailability was also evaluated. The rheological properties of doughs, batters and emulsions enriched with microalgae (Spirulina, Chlorella and Dunaliella) indicated that their viscoelastic behaviour was modified and improved, showing characteristics suitable for this type of products. The addition of microalgae (Spirulina and Chlorella) to the doughs and batters used for the 3D printing of cookies and snacks, allowed a better extrusion or printing behaviour. This allowed obtaining cylindrical 3D printed samples, more precise in terms of their dimensions with respect to the designed cylindrical structure. In addition, the 3D microalgae-printed sample structures presented greater stability and resistance, before and after the baking process compared to the control sample. For baked products, both for breadsticks and 3D printed snacks, the addition of microalgae (Spirulina and Chlorella) allowed greater stability in terms of texture. Slight changes in the physicochemical and expansion parameters were produced by the addition of Spirulina and Chlorella in the extruded products. In addition, the extrudates enriched with Nannochloropsis, showed similar parameters to those of the control sample. Microalgae-enriched obtained products showed bright colours with appealing appearances. Regarding minerals, an increase in P, K, Ca, Na, Mg, Fe and Se was observed with the addition of Spirulina and Chlorella, along the increase of concentration of microalgae addition. Following the regulations on nutrition labelling for food stuffs, breadstick enrichment with microalgae are a food "high in iron (Fe)" In the same way, breadsticks and cookies enriched with microalgae can be considered a "high in selenium (Se)" food. Going a step further, Spirulina and Chlorella vulgaris incorporation in cookie formulations allowed for greater bioaccessibility of P, K, Ca, Mg, Fe, Zn, and Se content for absorption in the body than control cookies. / Uribe Wandurraga, ZN. (2020). Microalgae as novel ingredients for the formulation of food products [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/158743 / Compendio