The equilibrium theory of island biogeography provides a useful model for understanding patterns of species richness on island systems and analogous fragmented terrestrial habitats. However, like all models, it is limited in its ability to explain island species richness patterns when nutrients move across ecosystem boundaries. Recently, enhancements to the theory have been proposed, including the subsidized island biogeography hypothesis. This hypothesis suggests that nutrient subsidies from the marine environment may impact the productivity and diversity of small islands. Sea wrack (dead, shore-cast seaweed) is a recognized vector of marine-nutrient subsidies to islands in regions of low in situ productivity, but little is known about the mechanisms surrounding sea wrack accumulation in productive, temperate environments. In this research I explore the spatial and temporal distribution of sea wrack on islands along British Columbia’s temperate Central Coast. Through an observational study I investigate three broad factors that could affect sea wrack deposition: climatic patterns, physical characteristics of shorelines, and the amount of nearby donor habitat. I surveyed sea wrack biomass and species composition, as well as the biogeographical characteristics of shorelines across 455 sites on 101 islands. I returned to a subset of sites on a bi-monthly basis to document temporal changes in wrack biomass and species composition. My results demonstrate that sea wrack accumulations were present at sites that were not composed of rock substrate, and that had wide, wave protected shorelines and high amounts of nearby donor ecosystem habitat. Additionally, sea wrack biomass and species composition was ubiquitous throughout all seasons. These results suggest that sea wrack can be considered a press subsidy as it is a consistent vector of nutrients to beaches along the Central Coast. Ecological research on macrophytes, macroalgae and sea wrack often requires the conversion of wet biomass to dry, to create consistency across investigations. This is a laborious process. Here, I present the results of wet-dry calibrations for 12 common macrophyte and macroalgae species collected from the Northeast Pacific Ocean. Future investigators can use the correction factors derived from these results for estimating dry biomass, reducing the need to conduct wet-dry calibrations for each new macrophyte, macroalgae, or sea wrack study. / Graduate

Orientadores: Maria Regina Wolf Maciel, Reinaldo Gaspar Bastos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-22T08:48:28Z (GMT). No. of bitstreams: 1 Klein_BrunoColling_M.pdf: 2562214 bytes, checksum: f891de86d253786cf5d2101fec1f3eba (MD5) Previous issue date: 2013 / Resumo: A busca por uma maior sustentabilidade tem levado a uma mudança em direção à utilização de fontes renováveis para geração de energia em detrimento do uso de combustíveis fósseis, visando a uma modificação na matriz energética global. A utilização da biomassa de microalgas para produção de biocombustíveis vem sendo vista como uma alternativa promissora, uma vez que o seu cultivo proporciona produtividades em carboidratos e lipídios superiores às matérias-primas vegetais convencionalmente utilizadas na obtenção de etanol e biodiesel. Neste contexto, o objetivo da presente dissertação de mestrado foi avaliar a produção de biomassa da microalga clorofícea Chlorella vulgaris em fotobiorreator de placa plana em diferentes condições de fluxo luminoso, concentração de CO2 na alimentação gasosa e concentração de NaNO3 no meio de cultivo, visando o acúmulo de carboidratos para obtenção de bioetanol de terceira geração. As influências das variáveis nutricionais e de processo sobre a eficiência fotossintética das microalgas também foram estimadas para determinação do estado fisiológico das culturas. A produtividade média de biomassa e a concentração máxima final das microalgas foram significativamente afetadas pela incidência de radiação luminosa e pela suplementação de CO2 gasoso, obtendo-se maiores produtividades de carboidratos em cultivos com alto fluxo luminoso e concentrações de CO2 intermediárias (7,5%). Também foi observado o efeito positivo do aumento do fotoperíodo sobre o crescimento das microalgas. Através de hidrólise ácida foi possível atingir concentrações de até 2 g L-1 de açúcares fermentescíveis no hidrolisado a partir de biomassa de microalgas cultivadas em meio com baixo teor de nitrogênio. A fermentação etanólica foi então conduzida com a levedura Dekkerabruxellensis capaz de converter diferentes hexoses e pentoses em bioetanol, dada a presença de ambos os tipos de açúcares no hidrolisado / Abstract: The search for industrial processes with higher sustainability has led to a change towards the utilization of renewable sources for energy generation in substitution of fossil fuels, aiming the modification of the global energy matrix. The utilization of microalgal biomass for the production of biofuels is viewed as a promising alternative, since its cultivation yields carbohydrate and lipid productivities superior to those of conventional sources used in the obtention of bioethanol and biodiesel. In this context, the goal of this master thesis was to evaluate the biomass production of the chlorophycean microalga Chlorella vulgaris in a flat plate photobioreactor under different conditions of light flux, CO2 concentration in the gas feed and NaNO3 concentration in the culture medium, aiming carbohydrate accumulation for the production of third generation bioethanol. The influences of both process and nutritional variables on the photosynthetic efficiency of microalgae were estimated for the determination of the physiological condition of the cultures. The mean biomass productivity and the maximum final microalgae concentration were significantly affected by the incidence of light radiation and by the supplementation of gaseous CO2, the highest carbohydrate productivities being obtained in cultivations with high light flux and intermediate CO2 concentrations (7,5%). It was also observed the positive effect of increasing the photoperiod over microalgae growth. Through acid hydrolysis, it was possible to attain fermentable sugar concentration of up to 2 g L-1 from biomass of microalgae cultivated in low-nitrogen medium. The ethanolic fermentation was then carried out with the Dekkerabruxellensis yeast, capable of converting different hexoses and pentoses into ethanol, due to the presence of both sugar types in the hydrolysate / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Neste trabalho, foi estudado o potencial biotecnológico, com ênfase na produção de biodiesel, de 25 espécies de macroalgas marinhas pertencentes às divisões Rhodophyta, Chlorophyta e Heterokontophyta coletadas no litoral brasileiro, avaliando-se a sua composição bioquímica e a sua taxa de fotossíntese. Também foram realizados estudos com 6 espécies de macroalgas coletadas na Baía do Almirantado, na Península Antártica, para comparar os resultados apresentados por esses organismos, que habitam um ambiente de condições extremas e adversas. Para a análise bioquímica, foram quantificados os pigmentos (clorofila a, para todos os grupos de macroalgas, e ficobiliproteínas -aloficocianina, ficocianina e ficoeritrina-, para as algas vermelhas), as proteínas e carboidratos solúveis totais e os lipídeos totais e ácidos graxos. As espécies Dictyota menstrualis e Ulva lactuca apresentaram os maiores valores de fotossíntese máxima. Foram observadas diferenças no conteúdo de clorofila a entre as espécies de macroalgas estudadas, sendo que os valores variaram de 0,20 ± 0,01 mg/g massa seca (Gigartina skottsbergii) a 6,82 ± 0,46 mg/g massa seca (Spatoglossum schroederi). Também houve grande variação no conteúdo de lipídeos, carboidratos e proteínas, sendo que os maiores valores foram encontrados em D. menstrualis (98,8 + 4,9 mg/g massa seca de lipídeos), Gracilaria mammillaris, Laurencia dendroidea e Plocamium cartilagineum (742,0 ± 31,9, 675,3 ± 11,0 e 660,2 ± 27,2 mg/g massa seca de carboidratos, respectivamente) e Palmaria decipiens e Aglaothamnion uruguayense (21,7 ± 1,7 e 18,0 ± 0,4 mg/g massa seca de proteínas, respectivamente). Houve grande variação na concentração e no perfil de ácidos graxos das espécies estudadas, sendo que D. menstrualis e S. schroederi foram as espécies que apresentaram os maiores valores. Além disso, D. menstrualis exibiu a maior proporção de ácidos graxos monoinsaturados. A partir dos resultados obtidos com as algas coletadas em campo, concluímos que D. menstrualis foi a espécie que apresentou as melhores características para ser utilizada como fonte para produção de biodiesel, devido a sua alta taxa fotossintetizante, alto teor de lipídeos e ácidos graxos e alto teor de ácidos graxos monoinsaturados. Dessa forma, D. menstrualis foi utilizada na segunda etapa do trabalho, sendo estabelecido o seu cultivo em laboratório, com uma taxa de crescimento (TC) de 11,1 % d-1. Foram realizados experimentos para avaliar os efeitos do aumento da concentração de dióxido de carbono (CO2), em condições de limitação e saturação de nitrogênio (na forma de nitrato, NO3-), sobre a TC, a fotossíntese, a atividade das enzimas nitrato redutase (NR), Anidrase Carbonica (AC) e Rubisco e sobre a composição bioquímica de D. menstrualis cultivada em biorreatores e sobre a captação do CO2 por D. menstrualis cultivada em laboratório. A TC, o conteúdo de proteínas e de N total no tecido de D. menstrualis foram maiores nos tratamentos contendo NO3-, independente da adição de CO2. Entretanto, houve um aumento nos valores de fotossíntese máxima, na atividade da Rubisco e NR, e no teor de carboidratos e lipídeos totais quando D. menstrualis foi cultivada em meio com adição de CO2, com saturação de NO3-. Houve pouca variação na atividade da AC entre os diferentes tratamentos testados. O perfil de ácidos graxos de D. menstrualis cultivada nos biorreatores foi caracterizado por um alto conteúdo de ácidos graxos poliinsaturados, com destaque para os omegas-3. Não houve diferença significativa na taxa de remoção de CO2 entre os tratamentos com e sem adição NO3-. A remoção de CO2 nos meios com e sem adição de CO2 foi alta, variando de 71,5% a 34,8%, respectivamente. Os resultados evidenciam que quando essa espécie foi cultivada em biorreatores, houve um aumento no seu teor de ácidos graxos poliinsaturados e ω-3, o que a torna mais interessante para ser utilizada como nutracêutico do que como matéria-prima para a produção de biodiesel. Apesar disso, a sua aplicação como fonte de biodiesel não deve ser desconsiderada, uma vez que alterações nas condições de cultivo acarretam em modificações no perfil de ácidos graxos. Com base nos resultados obtidos, as perspectivas para a produção de biodiesel a partir de macroalgas marinhas deverão contemplar estudos para encontrar as melhores condições de cultivo para que ocorra o aumento na biossíntese de ácidos graxos monoinsaturados. / The Biotehcnological potential, with biodiesel producing emphasis, on 25 species of marine benthic algae from the phylum Rhodophyta, Chlorophyta and Heterokontophyta collected along the Brazilian coast, were evaluated assessing their biochemical composition and their photosynthetic rate. Studies have also been performed with 6 seaweed species collected in Admiralty Bay, Antarctic Peninsula, to compare the results presented by these organisms inhabiting an environment of extreme and adverse conditions. For biochemical analysis, pigments (chlorophyll a, for all groups of macroalgae, and phycobiliproteins, allophycocyanin, phycocyanin and phycoerythrin, for the red algae), total soluble protein, total soluble carbohydrates and total lipids and fatty acids were quantified. The species Dictyota menstrualis and Ulva lactuca showed the highest values of maximum photosynthesis. There were differences in chlorophyll a content between the seaweeds studied, and the values ranged from 0.20 ± 0.01 mg / g dry mass (Gigartina skottsbergii) to 6.82 ± 0.46 mg / g dry weight (Spatoglossum schroederi). There was also wide variation in the content of lipids, carbohydrates and proteins, and the highest values were found in the species Dictyota menstrualis (98.8 ± 4.9 mg / g dry weight of lipids), Gracilaria mammillaris, Laurencia dendroidea and Plocamium cartilagineum (742, O ± 31.9, 675.3 ± 11.0 and 660.2 ± 27.2 mg / g dry weight of carbohydrates, respectively) and Palmaria decipiens and Aglaothamnion uruguayense (21.7 ± 1.7 and 18.0 ± 0, 4 mg / g dry weight of proteins, respectively). There was a wide variation on fatty acids contents and profile of the species studied; D. menstrualis and Spatoglossum schroederi showed the highest lipids values. In addition, D. menstrualis exhibited the highest proportion of monounsaturated fatty acids. From the results obtained with algae collected in the field, D. menstrualis is the species with the best characteristics to be used as a source for biodiesel production due to their high photosynthetic rate, high content of lipids and fatty acids and a high content of monounsaturated fatty acids. Thus, D. menstrualis was used in the second stage of this study, being established it\'s cultivation in the laboratory, with a growth rate (GR) of 11.1% d-1. Experiments to evaluate the effect of increasing carbon dioxide (CO2) concentration, under nitrogen (NO3-) limiting and saturation conditions, on the GR, photosynthesis, the activity of nitrate reductase (NR), carbonic anhydrase (CA) and Rubisco and on the biochemical composition of D. menstrualis grown in bioreactors and on the CO2 capture by D. menstrualis grown in the laboratory were performed. The GR, protein content and N content in the tissue of D. menstrualis were higher in treatments containing NO3-, regardless of the addition of CO2. However, there was an increase in the values of maximum photosynthesis, of Rubisco and NR activity, and of total soluble carbohydrates and total lipids when D. menstrualis was grown in medium with addition of CO2, with NO3- saturation. There was little variation in the AC activity among different treatments. The fatty acid profile of D. menstrualis cultivated in bioreactors was characterized by a high content of polyunsaturated fatty acids, especially the omegas-3. There was no significant difference in the rate of CO2 removal between treatments with and without NO3-. CO2 removal in medium with and without addition of CO2 was high, ranging from 71.5% to 34.8%, respectively. The results show that when this species was cultivated in bioreactors, there was an increase in its content of polyunsaturated fatty acids and ω-3, which makes it interesting for use as a nutraceutical than as raw material for biodiesel production. Nevertheless, its application as a source of biodiesel can not be disregarded, since changes in culture conditions lead to changes in fatty acid profile. Based on these results, the prospects for the production of biodiesel from marine macroalgae should include studies to find the best growing conditions to occur the increase in the monounsaturated fatty acids biosynthesis.

Batch equilibrium and dynamic column studies were undertaken to compare the metal-removal capabilities of two natural, low-cost materials (dried, crushed brown seaweed and shrimp shells) with a commercially available strong acid cation exchange resin (CER). All media maintained structural and hydraulic integrity over the duration of the column experiments. The batch tests showed that the low-cost materials demonstrated high adsorption capacities and affinities to Pb, Cu, Cd and Zn, but were slightly outperformed by the CER. Metal removal by each media was far superior to that reported for other types of low cost materials. Fixed beds of each media reduced concentrations of the target metals in a synthetic drainage water solution to levels below reference values measured at a case study site. This result suggests that any of the materials tested have the potential to completely remove impacts of a point source of metal contamination on the local water regime at the site. The CER column sustained the longest service time without large-scale breakthrough of any metal.

<p>The lack of a thorough understanding of the solidification behaviors of the proeutectic Al₃Sc and the Al-Al₃Sc eutectic in a hypereutectic Al-Sc alloy stimulates the present dissertation. The major findings for the single-phase growth of the proeutectic Al₃Sc is summarized as follows: At a low cooling rate (~1 ºC·s^-1), the proeutectic Al₃Sc phase’s formation was governed by the lateral growth, exposing six flat {100} facets. At an intermediate cooling rate (~400 ºC·s^-1), the proeutectic Al₃Sc grew in a dendritic manner, with well-defined backbones extending in eight <111> directions and paraboloidal dendrite tips, although the dendrite tips and side-branches turned into faceted steps at a late growth stage,when the lateral growth prevailed. At a high cooling rate (~1000 ºC·s^-1), the proeutectic Al₃Sc primarily crystallized into an entirely seaweed-structured particle, which was composed of interior compact seaweeds and exterior fractal seaweeds. In order to verify the proposed dendritic and seaweed growth mechanisms for the proeutectic Al₃Sc, various morphological stability criteria were used, and fair agreement between the observed and the estimated characteristic length scales was reached.</p><p>On the Al-Al₃Sc eutectic side, it was found that a rod-typed Al₃Sc eutectic phase prevalently existed in an as-cast hypereutectic Al-Sc alloy that solidified via both slow cooling in air (~1 ºC·s⁻¹) and rapid cooling in a wedge-shaped copper mold (up to ~3000 ºC·s⁻¹). Al-Al₃Sc eutectic dendrites were identified within a narrow region near the edge of the wedge. The eutectic dendrites had an equiaxed dendritic contour and a rod eutectic structure inside. Quantitative assessments revealed that an interface undercooling of 48.2 ºC was required to form the eutectic dendrites, or in other words, to enter the coupled zone of the Al-Al₃Sc phase diagram. Furthermore, a phenomenon of scientific interest was discussed: When crystallizing under a near-equilibrium condition, the eutectic Al₃Sc phase formed a non-faceted morphology, in contradiction to its faceted nature. Based on the competitive growth criterion, it was deduced that the non-faceting of the eutectic Al₃Sc phase essentially reduced the interface undercooling for the resultant regular eutectic, in comparison to an otherwise irregular eutectic that would contain a faceted eutectic Al₃Sc phase.</p>

Cellulase-producing microorganisms are considered as a key player in various environments to degrade the plant biomass and were isolated from various environment like soils, mangroves and oceans. The Red Sea has a unique environment in terms of high seawater temperature, high salinity and low nutrients. This study aims of examining if the Red Sea is a potential resource for cellulase-producing microorganisms and cellulase genes. First, I investigated types of microbial cellulase genes in the Red Sea based on public metagenomic datasets. The analysis revealed 3,383 microbial cellulase were more abundant in shallow depth than in deep seawater, and were classified into 16 sub-GH orthologous groups. These results suggest that the Red Sea environment is potentially an excellent gene resource of microbial cellulases due to its high diversity. Next, cellulase-producing microorganisms were isolated and screened from the Red Sea. Three bacterial and one fungal strain were successfully obtained. The MLTS analysis showed that the three bacterial strains belong to Bacillus paralichiniformis. The 18S rRNA of fungal strain showed 99% similarity to Aspergillus ustus and the enzymatic assay of the four strains showed high cellulase activity. These results suggest that these four isolates secreted active cellulases. Next, I tried to identify cellulase genes actually working during their cellulolysis by conducting comparative transcriptome analysis of the candidate genes and identified cellulase genes that are highly expressed during cellulolysis. To my knowledge, it is the first attempt to find out cellulase genes functioning during their cellulolysis among distinct cellulases on genomes of microorganisms. The results showed that although all the candidate genes were upregulated in general, a limited number of cellulase genes were highly expressed, which are highly expected to have a crucial role in cellulolysis. I also identified operon structures composed of genes including cellulases. This will provide us with the information to elucidate the cellular mechanisms occurring along with the cellulolysis in bacterial strains. We can expect that the Red Sea is a potential resource for new cellulase genes applicable for the industry. These information can be significantly useful for the bio-prospecting research of microbial cellulases in the Red Sea.

Red seaweeds are reported to represent the largest group of algae, with more species accounted for than the combination of brown and green seaweeds. Due to the high amount of polysaccharides in red seaweeds, they are mainly utilized for commercial agar and carrageenan production in industry. However, increasing studies indicate other valuable compounds such as lipids and polyphenols could be potential utilized for multiple human needs (e.g., drug development) (1, 2). With increasing studies demonstrating the potential health benefits of seaweed components, two red seaweed species commonly consumed in Asia, hong qı´ lı´n c a`i (HQL), Eucheuma sp and zhe` gu¯ ca`i (ZGC), Caloglossa leprieurii, were investigated on to determine the anti-inflammatory effects of their extractable lipophilic bioactives (ELB) and bound lipophilic bioactives (BLB) in lipopolysaccharide( LPS)-treated RAW 264.7 macrophages. The chemical composition of ELB and BLB was characterized in terms of total phenolic content (TPC), total flavonoid content (TFC), total tannin content (TTC), oxygen radical absorbance capacity (ORAC), and etc. Six phenolic compounds were identified in ZGC extracts and one was detected in HQL. All extracts inhibited the nitric oxide (NO) production in LPS-induced macrophages, which was associated with downregulation of iNOS and COX-2 protein expression and up-regulation of HQ-1 and NQO1 protein expression. Overall, our results showed that both ELB and BLB in HQL and ZGC seaweeds presented potential anti-inflammatory activities. These results warrant future investigations to determine the mode of actions of red seaweed bioactives and their efficacy in humans.

Tesis por compendio / [ES] Esta tesis doctoral se centró en la valorización de diferentes fuentes de biomasa marina para desarrollar materiales biopoliméricos e ingredientes destinados a la industria alimentaria. Así pues, en la primera parte de la tesis, se llevó a cabo la valorización de la biomasa de diversas especies de algas con el objetivo de identificar compuestos de interés y evaluar su potencial para la producción de materiales biopoliméricos e ingredientes alimentarios ricos en proteínas. Entre estas especies se encontraba R. okamurae, un alga parda invasora que representa una amenaza para los ecosistemas marinos. No obstante, se demostró que esta especie posee un gran potencial como fuente sostenible de compuestos bioactivos, transformando su papel de amenaza en oportunidad. La biomasa de las algas rojas también destacó por su potencial en diversas aplicaciones, incluyendo el desarrollo de materiales rentables y respetuosos con el medio ambiente obtenidos mediante de un procesado mínimo. En este contexto, la composición y la estructura de las paredes celulares de las algas desempeñaron un papel fundamental para entender cómo se comporta cada especie durante el procesado y en las propiedades de las películas resultantes. Además de la producción de materiales, también se estudiaron las algas rojas como fuente de proteínas para el consumo humano. Aunque las algas nativas presentaron una baja digestibilidad, esta mejoró mediante su procesado. No obstante, a pesar de esta mejora en la digestibilidad, el procesado podía inducir la degradación de los aminoácidos más lábiles, lo que repercutía negativamente en la calidad nutricional de las proteínas. En la segunda parte de esta tesis, se exploraron varias especies de algas rojas para extraer agar de forma más eficiente mediante métodos simplificados, y se evaluó la idoneidad de los extractos obtenidos para desarrollar materiales biopoliméricos e hidrogeles para aplicaciones alimentarias. El grado de purificación del agar tuvo un impacto significativo en las propiedades finales tanto de las películas como de los hidrogeles. En el caso de las películas, las fabricadas con agar puro presentaron propiedades superiores; sin embargo, sufrieron cambios significativos en su estructura semicristalina durante el almacenamiento. Por el contrario, las películas derivadas de extractos de agar menos purificados mostraron una mayor estabilidad en el tiempo, sugiriendo su potencial como aditivo para reducir costes y mejorar la estabilidad de las películas de agar puro. En el caso de los hidrogeles, la purificación del agar condujo a la formación de hidrogeles con una resistencia y dureza más altas. Por otro lado, el protocolo de extracción simplificado produjo fracciones de agar menos purificadas que contenían compuestos adicionales como proteínas o polifenoles. Aunque esto dio lugar a hidrogeles menos rígidos y resistentes, podrían ser de interés para la producción de hidrogeles con propiedades bioactivas. En la tercera y última parte de la tesis, se abordó la valorización de los residuos industriales generados tras la extracción de alginato, con el propósito de obtener fracciones de celulosa mediante métodos simplificados para su aplicación en la producción de materiales biopoliméricos. En este contexto, se observó que los residuos de A. esculenta y S. latissima resultaron adecuados para la extracción de fracciones celulósicas, mientras que A. nodosum podría ser más interesante para la producción de extractos ricos en fucoidano. Las fracciones de celulosa con mayor pureza generaron películas con propiedades mecánicas y aspecto visual más deseables. En cambio, las fracciones menos purificadas presentaron una mayor barrera al vapor de agua. De acuerdo con los resultados, se determinó que la simple aplicación de un tratamiento alcalino puede producir fracciones de celulosa que dan lugar a películas con un equilibrio óptimo entre propiedades funcionales y eficiencia económica y medioambiental. / [CA] Aquesta tesi doctoral es va centrar en la valorització de diferents fonts de biomassa marina para desenvolupar materials biopolimèrics i ingredients destinats a la indústria alimentària. Així doncs, en la primera part de la tesi, es va dur a terme la valorització de la biomassa de diverses espècies d'algues amb l'objectiu d'identificar compostos d'interés i avaluar el seu potencial per a la producció de materials biopolimèrics i ingredients alimentaris rics en proteïnes. Entre aquestes espècies es trobava R. okamurae, una alga marró invasora que representa una amenaça per als ecosistemes marins. No obstant això, es va demostrar que aquesta espècie posseeix un gran potencial com a font sostenible de compostos bioactius, transformant el seu paper d'amenaça en oportunitat. La biomassa de les algues roges també va destacar pel seu potencial en diverses aplicacions, incloent-hi el desenvolupament de materials rendibles i respectuosos amb el medi ambient obtinguts mitjançant d'un processament mínim. En aquest context, la composició i l'estructura de les parets cel·lulars de les algues van exercir un paper fonamental per a entendre el comportament cada espècie durant el processament i en les propietats de les pel·lícules resultants. A més, també es van estudiar les algues roges com a font de proteïnes per al consum humà. Encara que les algues natives van presentar una baixa digestibilitat, aquesta va millorar mitjançant el seu processament. No obstant això, malgrat aquesta millora en la digestibilitat, el processament podia induir la degradació dels aminoàcids més làbils, la qual cosa repercutia negativament en la qualitat nutricional de les proteïnes. En la segona part d'aquesta tesi, es van explorar diverses espècies d'algues roges per a extraure agar de forma més eficient mitjançant mètodes simplificats, i es va avaluar la idoneïtat dels extractes obtinguts per a desenvolupar materials biopolimèrics i hidrogels per a aplicacions alimentàries. El grau de purificació de l'agar va tindre un impacte significatiu en les propietats finals tant de les pel·lícules com dels hidrogels. En el cas de les pel·lícules, les fabricades amb agar pur van presentar propietats superiors; no obstant això, van patir canvis significatius en la seua estructura semicristal·lina durant l'emmagatzematge. Per contra, les pel·lícules derivades d'extractes d'agar menys purificats van mostrar una major estabilitat en el temps, suggerint el seu potencial com a additiu per a reduir costos i millorar l'estabilitat de les pel·lícules d'agar pur. En el cas dels hidrogels, la purificació de l'agar va conduir a la formació d'hidrogels amb una resistència i duresa més altes. D'altra banda, el protocol d'extracció simplificat va produir fraccions d'agar menys purificades que contenien compostos addicionals com a proteïnes o polifenols. Encara que això va donar lloc a hidrogels menys rígids i resistents, podrien ser d'interés per a la producció d'hidrogels amb propietats bioactius. En la tercera i última part de la tesi, es va abordar la valorització dels residus industrials generats després de l'extracció d'alginat, amb el propòsit d'obtindre fraccions de cel·lulosa mitjançant mètodes simplificats per a la seua aplicació en la producció de materials biopolimèrics. En aquest context, es va observar que els residus de A. esculenta i S. latissima van resultar adequats per a l'extracció de fraccions cel·lulòsiques, mentre que A. nodosum podria ser més interessant per a la producció d'extractes rics en fucoidans. Les fraccions de cel·lulosa amb major puresa van generar pel·lícules amb propietats mecàniques i aspecte visual més desitjables. En canvi , les fraccions menys purificades van presentar una major barrera al vapor d'aigua. D'acord amb els resultats, es va determinar que la simple aplicació d'un tractament alcalí pot produir fraccions de cel·lulosa que donen lloc a pel·lícules amb un equilibri òptim entre propietats funcionals i eficiència econòmica i mediambiental. / [EN] This doctoral thesis focused on the valorization of different sources of marine biomass with the main purpose of developing biopolymeric materials and ingredients for the food industry. Thus, in the first part of the thesis, the valorization of biomass from different algae species was carried out to identify compounds of interest and assess their potential to produce biopolymeric materials and protein-rich food ingredients. Among these species was Ruguloperyx okamurae, an invasive brown seaweed that poses a threat to marine ecosystems. However, this species was shown to have significant potential as a sustainable source of bioactive compounds, transforming its role as a threat into a valuable opportunity. Red seaweed biomass was also highlighted for its potential in a variety of applications, including the development of cost-effective and environmentally friendly materials for food applications obtained through minimal processing. In this context, the composition and structure of the algal cell walls played a crucial role in understanding how each species behaves during processing and in the properties of the resulting films. In addition to the production of biopolymeric materials, red seaweeds were also studied as a source of proteins for human consumption. Although native seaweeds had low digestibility, this was improved through processing. However, it is important to note that, despite the improvement in digestibility, processing could induce the degradation of more labile amino acids, having a negative impact on the nutritional quality of the proteins. In the second part of this thesis, several species of red seaweeds were explored to extract agar more efficiently by simplified methods, and the suitability of the extracts obtained to develop biopolymeric materials and hydrogels for food applications was evaluated. It could be observed that the degree of agar purification had a significant impact on the final properties of both films and hydrogels. In the case of films, those made of pure agar exhibited superior properties; however, they underwent significant changes in their semicrystalline structure during storage. In contrast, those films derived from less purified agar extracts showed greater stability over time, suggesting the potential of less purified agars as additives to reduce costs and improve the stability of pure agar films. Regarding the hydrogels, agar purification led to the formation of hydrogels with significantly higher strength and hardness. On the other hand, the simplified extraction protocol produced less purified agar fractions containing other compounds such as proteins, polyphenols, and minerals. Although this resulted in less rigid and resistant hydrogels, this feature could be advantageous for the production of hydrogels with bioactive properties. In the third and last part of the thesis, the valorization of industrial wastes generated after alginate extraction was addressed, with the purpose of obtaining cellulosic fractions by simplified methods for their application in the production of biopolymeric materials. In this context, it was observed that the residues of Alaria esculenta and Saccharina latissima were suitable for the extraction of cellulosic fractions, while Ascophyllum nodosum might be more interesting for the production of fucoidan-rich extracts. Cellulosic fractions with higher purity produced films with more desirable mechanical properties and visual appearance. Conversely, less purified fractions presented a greater barrier to water vapor. According to the results, it was determined that the simple application of an alkaline treatment could produce cellulosic fractions that resulted in films with an optimal balance between functional properties and economic and environmental efficiency in biopolymeric material production. / This work was financially supported by the “Agencia Estatal de Investigación” (PCI2018-092886 Grant) and co-funded by the European Union’s Horizon 2020 research and innovation programme (ERA-Net SUSFOOD2) and by the grant TED2021-129711B-I00, funded by MCIN/AEI/10.13039/501100011033 and by the European Union NextGenerationEU/PRTR. This work was done within the framework of a collaboration with HISPANAGAR S.L (Burgos, Spain). The research was funded by the Spanish Ministry of Science, Innovation and Universities through projects PID2020-114821RB-I00, PID2020-117744RJ-I00, as well as CEX2021-001189-S, funded by MCIN/AEI/10.13039/501100011033. The authors also acknowledge funding through project CIRCALGAE (Horizon Europe) under grant agreement 101060607. In all projects, funding from “ERDF A way of making Europe”, the “European Union” or the “European Union NextGenerationEU/PRTR” is also acknowledged. / Cebrián Lloret, V. (2024). Valorization of Marine Biomass for the Development of Biopolymeric Materials and Additives with Functional Properties [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/202961 / Compendio

The nutrition bound in macroalgae, also known as seaweed, contains high amounts of all the nutrients, micronutrients, vitamins and plant hormones, necessary for plants, animals and humans. Totally for free it is floating in the oceans around the world and has been harvested and used by people for thousands of years. A problem that has arisen in the wake of Industrialism during the past 200 years is that human beings spread non-desirable substancesto air, water and soil, for example heavy metals. Macroalgae accumulate the heavy metals, which may become a problem if we want to eat seaweed or use it to grow plants in.  In a growth trial using macroalgal compost made from Fucus radicans collected from the Baltic Sea, the uptake heavy metals in the edible tubers of potatoes of the cultivar ‘Cherie’ was investigated. The following heavy metals were analyzed: lead(Pb), cadmium (Cd), mercury (Hg), arsenic (As) and copper (Cu). There were no differences in the uptake of heavy metal between potatoes grown in macroalgal compost and soil, but the potato tubers from both cultivations contained concentrations of Cd and As higher than those normally found in Swedish potatoes. The concentrations are, however, much lower than the limits set by EFSA. The macroalgal compost and the soil used in the experiment were also analyzed for heavy metal content. The Cd concentration in the compost exceeded the limit for Swedish compost. However, the high levels of Cd in the compost were not reflected in the Cd content of the potato tubers. Soil conductivity and pH values were also investigated. The high conductivityof the macroalgal compost was probably due to insufficient rinsing of the macroalgae, and thus it was not ideal for use in crop cultivation. In spite of this, the crop yield was good. In conclusion, macroalgal compost can be recommended as a cultivation substrate for potatoes. / Den näring som finns bunden i makroalger, även kallad tång, innehåller rikliga mängder av alla näringsämnen, spårämnen, vitaminer och växthormoner som växter, djur och människor behöver. Alldeles gratis flyter den omkring i världshaven och har skördats och använts av människan under tusentals år. Problemet som uppstått i industrialismens spår de senaste 200 åren är att människan sprider icke önskvärda ämnen till luft, vatten och jord, t.ex. tungmetaller. Makroalger ackumulerar dessa, vilket kan bli ett problem om vi vill äta eller odla i tång.  Vid ett odlingsförsök med potatis i tångkompost av Fucus radicans från Östersjön undersöktes metallupptaget i de ätbara knölarna i potatis av sorten ’Cherie’. De tungmetaller som analyserades var bly (Pb), kadmium (Cd), kvicksilver (Hg), arsenik (As) och koppar (Cu). Analysrapporten visade ingen skillnad i upptag av tungmetaller mellan potatis som odlats i tångkompost eller i jord; däremot innehöll knölarna från båda odlingarna högre halter av kadmium och arsenik än normalvärdena i svensk potatis. Halterna är dock långt under EFSA:s gränsvärden. Även odlingssubstraten, dvs. tångkomposten och jorden undersöktes för tungmetallförekomst. Kadmiumhalterna i tångkomposten översteg gränsvärdet för svenska kompostjordar, men de höga kadmiumhalterna reflekterades inte i potatisknölarnas kadmiuminnehåll. Odlingssubstratens ledningstal och pH-värden undersöktes också. Tångkompostens höga ledningstal (10,8 mS/cm) berodde antagligen på otillräcklig sköljning och gjorde den inte idealisk för odling. Trots detta blev skördeutfallet gott. Således kan tångkompost rekommenderas som odlingssubstrat för potatis.

O oceano apresenta uma vasta diversidade de espécies, entre elas as algas marinhas, as quais são usadas principalmente como fonte de alimentos, de produtos industriais e para uso medicinal. Considerando a biodiversidade encontrada, são poucos os estudos que verificam a composição química e atividade biológica de algas. Desta forma, o presente trabalho descreve especialmente compostos do metabolismo primário (lipídios, proteínas e aminoácidos), composição química volátil, e potencial antioxidante e antimicrobiano de quatro espécies de algas vermelhas da costa brasileira (Laurencia filiformis, Laurencia intricata, Plocamium brasiliense e Ochtodes secundiramea). As análises de lipídeos revelaram que estas algas são ricas em ácidos graxos poliinsaturados &#969;3 e &#969;6, mas que apresentam o ácido palmítico como majoritário. O teor de proteínas encontrado é considerável e aproximadamente 50% da composição de aminoácidos é de aminoácidos essenciais. Para extrair os compostos voláteis das algas selecionadas para o estudo, três métodos foram utilizados: arraste a vapor, extração por solvente e HS-SPME. A caracterização química dos compostos voláteis deu-se principalmente pela utilização de cromatografia gasosa acoplada à espectrometria de massas (CG-EM). Ainda foram isolados e identificados dois compostos majoritários do óleo essencial de L. filiformis, o (-)-7-epi-silfiperfolan-6&#946;-ol e o (-)-silfiperfolan-7&#946;-ol, e quatro compostos do extrato acetona/água de P. brasiliense, o 3,4-eritro-7-diclorometil-3-metil-3,4,8-tricloro-1,5(E),7(E)-octatrieno; o 3,4-eritro-7-diclorometil-3-metil-3,4,8-tricloro-1,5(E),7(Z)-octatrieno; o 3,4-eritro-1-bromo-7-diclorometil-3-metil-3,4,8-tricloro-1(E),5(E),7(E)-octatrieno e o 3,4-eritro-1-bromo-7-diclorometil-3-metil-3,4,8-tricloro-1(E),5(E),7(Z)-octatrieno, utilizando diferentes técnicas cromatográficas, como CCDP e CLAE, para isolamento, e técnicas espectroscópicas (RMN uni e bidimensionais) e espectrométricas (HRMS e EIMS) para análise. A atividade antioxidante dos óleos essenciais, dos extratos e das substâncias isoladas foi verificada utilizando-se dois métodos (DPPH e quimioluminescência). Os extratos diclorometano de L. filiformis (IC50 de 48,5 &#181;g/mL) e L. intricata (IC50 de 58,0 &#181;g/mL) mostraram-se como os mais potentes. As mesmas amostras não apresentaram potencial antimicrobiano em concentrações de até 500 &#181;g/mL frente aos nove microrganismos testados. / The ocean provides large diversity of species, among them the seaweeds, which are mainly used as food, industrial products and as medicine. Considering the biodiversity, there are only few studies which analize the algae volatile compounds and their biological activity. So that, this work describes specially compounds from the primary metabolism (lipids, proteins and amino acids), chemical volatile composition, and antioxidant and antimicrobial potencies of four red algae of the Brazilian coast (Laurencia filiformis, Laurencia intricata, Plicamium brasiliense and Ochtodes secundiramea). The lipid analysis showed that these algae have &#969;3 and &#969;6 polyunsaturated fatty acids, but the palmitic acid is the most abundant. The protein content observed is considerable and approximately 50% of the amino acid composition is of essential amino acids. To extract the volatile organic compounds from the algae selected for this study, three methods were used: hydrodestilation, solvent extraction and HS-SPME. For chemical characterization of the volatile compounds, the technique used was gas chromatography coupled with mass spectrometry (GC-MS). In addition, the two most abundant compounds from the essential oil of L. filiformis, the (-)-7-epi-silphiperfolan-6&#946;-ol and the (-)-silphiperfolan-7&#946;-ol, and four compounds of the aceton/water extract of P. brasiliense the 3,4-erythro-7-dichloromethyl-3-methyl-3,4,8-trichloro-1,5(E),7(E)-octatriene; the 3,4-erythro-7-dichloromethyl-3-methyl-3,4,8-trichloro-1,5(E),7(Z)-octatriene; the 3,4-erythro-1-bromo-7-dichloromethyl-3-methyl-3,4,8-trichloro-1(E),5(E),7(E)-octatriene and the 3,4-erythro-1-bromo-7-dichloromethyl-3-methyl-3,4,8-trichloro-1(E),5(E),7(Z)-octatriene, were isolated and identified using different chromatographic techniques like preparative TLC and HPLC for isolation and spectroscopic (NMR uni and bidimensional) and spectrometric techniques (HRMS and EIMS) for analysis. The antioxidant activity of the essential oils, of the extracts and of the isolated compounds was verified by two methods (DPPH and chemiluminescence). The dichloromethane extracts of L. filiformis (IC50 of 48.5 &#181;g/mL) and L. intricata (IC50 de 58.0 &#181;g/mL) showed higher potency. The same samples do not have antimicrobial activity in concentrations until 500 &#181;g/mL up against the nine microorganisms tested.