Lim Sze Nee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 165-176). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese Version) --- p.iii / Acknowledgements --- p.v / Table of Contents --- p.vi / List of Tables --- p.xi / List of Figures --- p.xiii / List of Abbreviation --- p.xvii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1. --- General Introduction --- p.1 / Chapter 1.1 --- Classification of algae --- p.2 / Chapter 1.2 --- Chemical and mineral composition of marine macroalgae --- p.4 / Chapter 1.3 --- Uses of marine macroalgae --- p.7 / Chapter 1.3.1 --- Food --- p.7 / Chapter 1.3.2 --- Industrial uses --- p.8 / Chapter 1.3.3 --- Agricultural uses --- p.9 / Chapter 1.3.3.1 --- Fertilizer --- p.9 / Chapter 1.3.3.2 --- Fodder --- p.9 / Chapter 1.3.4 --- Medicinal properties --- p.10 / Chapter 1.4 --- Pharmacological effects of marine macroalgae --- p.11 / Chapter 1.4.1 --- Antioxidant activity --- p.11 / Chapter 1.4.2 --- Hypotensive activity --- p.11 / Chapter 1.4.3 --- Antiviral activity --- p.12 / Chapter 1.4.4 --- Antimicrobial activity --- p.12 / Chapter 1.4.5 --- Antitumor activity --- p.13 / Chapter 1.4.6 --- Hypocholesterolemic activity --- p.14 / Chapter 1.5 --- Objectives --- p.14 / Chapter CHAPTER 2 --- Free Radical Scavenging and Antioxidative Activities of Marine Macroalgae --- p.16 / Chapter 2.1 --- Introduction --- p.16 / Chapter 2.1.1 --- Free radicals: definition and sources --- p.16 / Chapter 2.1.2 --- Free radical-induced damage --- p.16 / Chapter 2.1.2.1 --- Biological lipid peroxidation --- p.16 / Chapter 2.1.2.2 --- Lipid oxidation of foods --- p.18 / Chapter 2.1.3 --- Antioxidants --- p.19 / Chapter 2.1.3.1 --- Antioxidants --- p.19 / Chapter 2.1.3.2 --- Antioxidant mechanisms --- p.20 / Chapter 2.1.4 --- Synthetic antioxidants --- p.21 / Chapter 2.1.5 --- Natural antioxidants --- p.24 / Chapter 2.1.6 --- Objectives --- p.27 / Chapter 2.2 --- Methods and Materials --- p.28 / Chapter 2.2.1 --- Preparation of algae extracts --- p.28 / Chapter 2.2.2 --- Determination of free radical scavenging activities --- p.32 / Chapter 2.2.2.1 --- Superoxide anions scavenging activity --- p.32 / Chapter 2.2.3 --- Antioxidative activity using hemolysis assay --- p.33 / Chapter 2.2.3.1 --- Preparation of red blood cell (RBC) --- p.33 / Chapter 2.2.3.2 --- Hemolysis assay --- p.33 / Chapter 2.2.4 --- Lipid peroxidation assay --- p.34 / Chapter 2.2.4.1 --- Preparation of rat brain homogenates --- p.34 / Chapter 2.2.4.2 --- Measurement of lipid peroxidation --- p.34 / Chapter 2.2.5 --- Statistics --- p.35 / Chapter 2.3 --- Results --- p.36 / Chapter 2.3.1 --- Superoxide radical scavenging activity of algal extracts --- p.36 / Chapter 2.3.2 --- Effects of algae extracts on hemolysis assay --- p.41 / Chapter 2.3.3 --- Effects of algae extracts on lipid peroxidation --- p.44 / Chapter 2.4 --- Discussion --- p.50 / Chapter CHAPTER 3 --- Isolation of Antioxidative Phenolic Compounds from Sargassum siliquastrum --- p.60 / Chapter 3.1 --- Introduction --- p.60 / Chapter 3.1.1 --- Phenolic compounds --- p.60 / Chapter 3.1.2 --- Major classes of phenolic compounds --- p.60 / Chapter 3.1.3 --- Functional aspects of phenolic compounds --- p.61 / Chapter 3.1.3.1 --- Functions of phenolic compounds in plants --- p.61 / Chapter 3.1.3.2 --- Biological and pharmacological activities --- p.64 / Chapter 3.1.3.3 --- Food industry --- p.65 / Chapter 3.1.4 --- Polyphenolic compounds in brown algae --- p.66 / Chapter 3.1.5 --- Objectives --- p.68 / Chapter 3.2 --- Methods and Materials --- p.69 / Chapter 3.2.1 --- Extraction and isolation of antioxidant components from S siliquastrum --- p.69 / Chapter 3.2.2 --- Thin-Layer chromatography --- p.70 / Chapter 3.2.3 --- Antioxidant activity --- p.71 / Chapter 3.2.4 --- Determination of total phenolics --- p.71 / Chapter 3.2.5 --- Infrared spectra --- p.72 / Chapter 3.2.6 --- Ultra-violet and visible (UV-vis) spectrophotometry --- p.72 / Chapter 3.2.7 --- Statistics --- p.73 / Chapter 3.3 --- Results --- p.73 / Chapter 3.3.1 --- Identification of phenolic compounds from various solvent extracts of S. siliquastrum --- p.73 / Chapter 3.3.2 --- Isolation of dichloromethane fraction by liquid chromatography --- p.81 / Chapter 3.3.3 --- Phenolic content of isolated compounds --- p.86 / Chapter 3.3.4 --- IR and UV-vis spectra --- p.86 / Chapter 3.4 --- Discussion --- p.92 / Chapter 3.4.1 --- Antioxidative activities --- p.92 / Chapter 3.4.2 --- Relationship between phenolic contents and antioxidant activity --- p.95 / Chapter 3.4.3 --- Identification of antioxidant compounds --- p.97 / Chapter CHAPTER 4 --- Hypotensive Activities of Marine Algae in the Rat --- p.102 / Chapter 4.1 --- Introduction --- p.102 / Chapter 4.1.1 --- Basic principles of cardiovascular system --- p.102 / Chapter 4.1.2 --- Regulation of arterial pressure --- p.105 / Chapter 4.1.2.1 --- Short-term regulation of arterial pressure --- p.105 / Chapter 4.1.2.2 --- Long-term regulation of arterial pressure --- p.107 / Chapter 4.1.3 --- Hypertension --- p.108 / Chapter 4.1.3.1 --- Causes of hypertension --- p.109 / Chapter 4.1.3.2 --- Where do antihypertensive or hypotensive agents act? --- p.114 / Chapter 4.1.3.2.1 --- Sympathetic nervous system inhibitors --- p.115 / Chapter 4.1.3.2.2 --- Diuretics --- p.120 / Chapter 4.1.3.2.3 --- Vasodilators --- p.121 / Chapter 4.1.3.2.4 --- Calcium antagonist (Calcium channel blockers) --- p.121 / Chapter 4.1.3.2.5 --- Angiotensin-converting enzyme (ACE) inhibitors --- p.122 / Chapter 4.1.3.2.6 --- Antihypertensive drug combination --- p.122 / Chapter 4.1.4 --- The relationship between hypertension and free radicals --- p.123 / Chapter 4.1.5 --- Development of new antihypertensive agenrs --- p.124 / Chapter 4.2 --- Materials and methods --- p.125 / Chapter 4.2.1 --- Animal care --- p.125 / Chapter 4.2.2 --- Preparation of the blood pressure measurement in rats --- p.125 / Chapter 4.2.2.1 --- Effects of seaweed extracts on arterial blood pressure of rat --- p.126 / Chapter 4.2.2.1.1 --- Single-dose response curve --- p.126 / Chapter 4.2.2.1.2 --- Cumulative-dose response curve --- p.126 / Chapter 4.2.2.2 --- Pharmacological blocker studies --- p.128 / Chapter 4.2.3 --- Statistics --- p.131 / Chapter 4.3 --- Results --- p.131 / Chapter 4.3.1 --- Hypotensive effects of marine algal extracts --- p.131 / Chapter 4.3.2 --- Effects of pharmacological blockers on MAP --- p.135 / Chapter 4.4 --- Discussion --- p.150 / Chapter 4.4.1 --- Hypotensive effects of the marine algal extracts --- p.150 / Chapter 4.4.2 --- Pharmacological action of marine algal extracts --- p.152 / Chapter CHAPTER 5 --- Conclusion --- p.160 / REFERENCES --- p.165 / RELATED PUBLICATIONS --- p.177

Zhu Wen. / "May 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 217-249). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Devido à grande importância que o gênero Eucalyptus apresenta, cada vez mais estudos relacionados à otimização da propagação de espécies do gênero vêm sendo conduzidos. Os principais entraves estão relacionados à sua clonagem e a recalcitrância que algumas espécies apresentam ao enraizamento e, por essa razão, o presente trabalho teve como objetivo avaliar o uso de bioestimulantes na mini e microestaquia de Eucalyptus spp. O presente trabalho se preocupou com o desenvolvimento de protocolos que não alteram excessivamente a prática empregada pelas empresas silviculturais. Para tanto, o trabalho foi dividido em 4 partes, sendo a primeira composta por uma revisão sobre enraizamento (item 2), visando elucidar todos os principais fatores que podem influenciar neste evento morfogênico. A partir desta revisão, se iniciaram estudos práticos com espécies e híbridos do gênero. O primeiro estudo (item 3) baseou-se na avaliação da morfofisiologia de miniestacas de três espécies de eucalipto (E. urograndis, E. benthamii e E. urophylla) em contato com AIB em pó e subsequente aplicação de tratamentos com bioestimulantes (ácido tânico e Algaren BZn®) utilizados de forma isolada e/ou em associação diretamente na base das miniestacas. O segundo estudo (item 4) avaliou a atuação destes mesmos tratamentos com bioestimulantes, em microcepas de Eucalyptus urograndis em fase de alongamento in vitro das brotações e sua posterior aclimatização. Por fim, o terceiro estudo (item 5) foi baseado na utilização dos tratamentos com bioestimulantes em microestacas de E. urophylla em fase de aclimatização em miniestufas, sendo os bioestimulantes aplicados na base das microestacas e na base das miniestufas (diretamente na bandeja). Em todos os experimentos foram coletados dados referentes aos parâmetros morfofisiológicos e, observou-se no primeiro e segundo experimento, que o ácido tânico na concentração de 250mg/L, foi o melhor tratamento empregado. Já, para o terceiro experimento, o Algaren BZn® na concentração de 1ml/L, apresentou resultados mais favoráveis. De acordo com as análises histológicas da rizogênese para todos os experimentos, verificou-se que as raízes adventícias desenvolvidas apresentaram origem cambial e conexão direta com o sistema vascular da parte aérea, indicando serem funcionais. O que permitiu constatar que, de forma geral, a adição de bioestimulantes otimizou a produção de mudas clonais de Eucalyptus. / According to the great importance that Eucalyptus genus presents, more studies are related to genus species propagation optimization have been conducted. Being the rooting recalcitrance that some species presents the main obstacle related to its cloning, this work had the aim to evaluate the biostimulants use in mini and microcuttings rooting process of Eucalyptus spp. For this, the present work was concerned with the protocols development that does not excessively alter the practice employed by silvicultural business. For this, the work was divided into 4 parts, the first have a rooting review (item 2), in order to elucidate all the main factors that may influence this morphogenic event. From this review, practical studies with species and hybrids of the genus were started. The first study (item 3) was based on the minicuttings morphology evaluation of the three eucalyptus species (E. urograndis, E. benthamii and E. urophylla) in contact with IBA in talc and the subsequent application of biostimulant treatments (tannic acid and Algaren BZn®) used in isolation and/or in combination directly on minicuttings base. The second study (item 4) evaluated the performance of these same treatments with biostimulants in E. urograndis microcuttings on the shoots elongation stage in vitro and their subsequent acclimatization. Finally, the third study (item 5) was based on the biostimulant treatments use in E. urophylla microcuttings in acclimatization phase in ministuff. The biostimulants were applied at microcuttings base and at ministuff base (directly on the trays). In all experiments, data regarding morphophysiological parameters were collected and it was observed in the first and second experiments that tannic acid at 250mg/L concentration was the best treatment used. For the third experiment, the Algaren BZn® in the concentration of 1 ml/L, presented more favorable results. According to the rhizogenesis histological analyzes for all the experiments, it was verified that the adventitious roots developed presented cambial origin and had a direct vascular connection with the aerial part, indicating its functionality. This showed that, in general, the biostimulants addition optimized the production of clonal Eucalyptus seedlings.

Damp, rotting, smelly, rising from the depths, washed up on shorelines. Seaweed (or Macroalgae) has transitioned over time in its position and uses within the British Isles; as discussed in the thesis it has undergone an evolution from its historical use as a source of food in times of desperation, to the superfood it is lauded as today. Other applications, from medicinal to agricultural, have contributed to a narrative of seaweed’s identity over the centuries, to the appeal of seaweed as a food source in the present day. There is an increased interest in seaweed, especially for culinary purposes, in the British Isles. Research by chefs, cookbooks and innovative product ranges also frame the current attitudes in the use of seaweed in common everyday foods. The case study shows the challenges and opportunities in the current revitalised seaweed market, identifying marketing analysis approaches useful for changing the attitudes toward seaweed in the British Isles. Based on interviews with companies marketing seaweed, and a focus on Seagreens®, I draw on advertising theory and consultancy tools (such as SWOT, AGCC, ELM and DAGMAR) to analyse the current seaweed market defining what I call a ‘consumer triad’ of potential consumers. Findings indicate many possibilities for future USP endorsements depending on the target market, from health-orientated to sustainably farmed. Seaweed interest appears to be more knowledge than consumer driven, so the question instead surrounds the prospect of knowledge sharing in an integrated online manner. Meanwhile, challenges in farming, labelling and conservation within the EU hamper advancements in the field, with the balance shifting to invested interest in Blue Economy models and IMTA systems.

As macroalgas marinhas constituem uma importante fonte de produtos naturais, devido à sua composição química, rica em substâncias fenólicas, terpenos e polissacarídeos sulfatados, apresentando potencial biotecnológico como fonte de substâncias com atividade antioxidante, antiviral, antitumoral e antibacteriana. Nesse sentido, o objetivo do presente estudo foi avaliar o potencial de prospecção de macroalgas do litoral do Espírito Santo (ES), mediante estudos dos potenciais antioxidante e bioativo de extratos brutos de quatro espécies de algas pardas (Chnoospora minima, Dictyopteris plagiogramma, Padina gymnospora e Sargassum cymosum) e de uma espécie de alga verde (Codium isthmocladum). A caracterização inicial dos extratos acetato de etila e metanólico das algas pardas, demonstrou a presença de constituintes com características distintas, indicando que pertencem à diferentes classes fenólicas. Os extratos metanólicos e aquosos das cinco espécies apresentaram os maiores rendimentos, sendo utilizados para análise do potencial antioxidante e bioativo. O extrato metanólico de P. gymnospora apresentou o maior potencial antioxidante e o maior teor de substâncias fenólicas totais pelo ensaio Folin-Ciocalteu, indicando o potencial dessa espécie como ingrediente funcional e na busca de substâncias antioxidantes naturais. As espécies analisadas apresentaram potencial bioativo (antiviral e antitumoral), sendo que os extratos aquosos foram mais ativos, quando comparados aos metanólicos. O maior potencial antiviral foi encontrado nos extratos aquosos de P. gymnospora, S. cymosum e C. isthmocladum, e o maior potencial antitumoral nos extratos aquosos de D. plagiogramma e C. isthmocladum. Tanto o potencial antiviral, como antitumoral podem estar relacionados à presença de substâncias fenólicas e polissacarídeos sulfatados nos extratos. Os resultados obtidos demonstram que as espécies estudadas, principalmente D. plagiogramma, P. gymnospora, S. cymosum e C. isthmocladum, apresentam potencial para prospecção de produtos naturais / Marine macroalgae are an important source of natural products, due to their chemical composition, rich in phenolic substances, terpenes and sulphated polysaccharides, presenting biotechnological potential as a source of substances with antioxidant, antiviral, antitumor and antibacterial activity. In this sense, the objective of the present study was to evaluate the potential of macroalgae prospecting on the coast of Espírito Santo (ES), through studies of the antioxidant and bioactive potentials of crude extracts of four species of brown seaweeds (Chnoospora minima, Dictyopteris plagiogramma, Padina gymnospora and Sargassum cymosum) and a species of green seaweed (Codium isthmocladum). The initial characterization of the ethyl acetate and methanolic extracts of the brown seaweeds, showed the presence of constituents with distinct characteristics, indicating that they belong to the different phenolic classes. The methanolic and aqueous extracts of the five species presented the highest yields, being used for analysis of the antioxidant and bioactive potential. The methanolic extract of P. gymnospora presented the highest antioxidant potential and the highest content of total phenolic substances by the Folin-Ciocalteu assay, indicating the potential of this species as a functional ingredient and the search for natural antioxidant substances. The analyzed species presented bioactive potential (antiviral and antitumor), and the aqueous extracts were more active when compared to methanolic. The highest antiviral potential was found in aqueous extracts of P. gymnospora, S. cymosum and C. isthmocladum, and the highest antitumor potential in aqueous extracts of D. plagiogramma and C. isthmocladum. Both antiviral and antitumoral potential may be related to the presence of phenolic substances and sulfated polysaccharides in the extracts. The results showed that the studied species, especially D. plagiogramma, P. gymnospora, S. cymosum and C. isthmocladum, present potential for the prospection of natural products

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.

Anaerobic digestion is a key energy and resource recovery technology. This work investigated potential organic waste resources to co-digest with household food waste (HFW) to stabilise the process and future-proof feedstock availability. This included novel feedstock macroalgae (seaweed) waste (SW). Hydrothermal (autoclave) pretreatment was also investigated to optimise energy recovery from HFW and SW. Preliminary experiments investigated the behaviour of HFW co-digested with either a green waste (GW) or paper waste (PW), using a batch-test laboratory scale and systematic approach with a revised waste mixture preparation method. Following preliminary trials, the co-digestion of HFW/SW was investigated using an air-dried SW mixture. Batch experiments to determine the biomethane potential (BMP) at different ratios of HFW to SW were set up. Co-digesting HFW and SW at ratio 90:10 (d.w.) achieved a BMP similar to HFW alone (252±13 and 251±1 cm3 g-1 VS, respectively), and a peak methane yield for HFW:SW (90:10) at day 12 of 69±3% compared to a peak methane yield for HFW at day 19 of 70±3%. Addition of SW optimised the C/N ratio, increased concentrations of essential micronutrients and produced an overall increase in reaction kinetics. Concentrations of SW ≥25%, associated with high sulphur levels, reduced final methane productivity. Analysis of the macroalgae strains L. digitata, U. lactuca and F. serratus from the SW mixture was carried out to compare mono-digestion and co-digestion with HFW at a 90:10 ratio and the effect of autoclave pretreatment at 136°C. Co-digestion had a positive impact on methane yields for U. lactuca and F. serratus, whilst autoclave pretreatment had no significant impact on the SW strains When results were modelled for a 320 m3 anaerobic digester treating 8m3 feed per day the theoretical energy balance showed that optimal energy production from pretreated HFW at 8.09 GJ/day respectively could be achieved. To verify the suitability of using macroalgae, known to readily uptake polycyclic aromatic hydrocarbons (PAH), toxicity tests were used to determine the impact of phenanthrene sorbed by U. lactuca on the AD process. Despite U. lactuca’s ability to biosorb phenanthrene in under 2 hours, no impact on the AD process was observed. Overall, results of this study demonstrated that co-digestion of HFW and SW, at batch laboratory scale, provide a viable and sustainable waste revalorisation solution. In addition, low temperature autoclave pretreatment increased methane production (p=0.002) from the AD of HFW.

Most ecologists work at scales where complexity is greatest ( i.e. local ), and it is not surprising, therefore, that we tend to be captivated by the description and explanation of local variation whilst being pessimistic about the existence of broader patterns. Using a character ( kelp morphology ) known for its local and unaccounted variation, the morphology of the canopy - forming algae Ecklonia radiata ( Phaeophyta ) was quantified across > 5000 km of temperate Australian coastline, ( i ) between different configurations of algal stand ( i.e. monospecific vs mixed - species stands ) and ( ii ) across multiple spatial scales. A key result was that despite variation at local scales ( km ), differences between stands became increasingly clear at broad scales ( 1000 ' s km ), which supports the idea that large - scale patterns can emerge from apparent stochasticity at small scales. Within each stand, regional scale differences in morphological characters were evident ( i.e. Western Australia = South Australia ≠ Eastern Australia ). These characters correlated with geographic and environmental variables to indicate that the majority of morphological variation across temperate Australia was accounted for by longitude, wave exposure, water temperature and plant density. Morphological differences associated with environmental factors may reflect a plastic response to the local environment, or alternatively may reflect genetically fixed traits ( i.e. ecotypes ). An independent test of morphological variation associated with wave exposure environments, using a reciprocal transplant experiment, revealed that morphological plasticity was the mechanism enabling E. radiata to adopt different morphologies between exposure environments. The presence of kelp canopies has strong spatial relationships with organisms growing underneath them, and variation in the morphology of these canopies may facilitate distinct assemblages within the understorey habitat. Variation in the morphology of E. radiata was found to be associated with the structure of understorey assemblages, over broad spatial scales. This canopy - understorey association revealed two ' types ' of kelp forest ; one characteristic of Western and Southern Australia and the other of Eastern Australia. Patterns of canopy - benthos association have mostly been done on horizontal surfaces and experimental tests showed that such patterns on horizontal surfaces were not representative of vertical surfaces, which enables us to recognize the conditions for which we can reliably anticipate the structure of benthic organisms, thereby improving the predictive power of models that account for widespread patterns in subtidal heterogeneity. In conclusion, this thesis suggests that there are fundamental differences between the ecology of kelp forests at local scales ( i.e. between types of stand ) and at regional scales ( i.e. between the south and east coast of temperate Australia ), reflecting differences in kelp morphology that may be caused by environmental conditions ( e.g. exposure ) and may influence associated taxa ( e.g. understorey ). Consideration of such local - scale variation ( specificity ) when testing for the existence of broad - scale phenomena ( generality ) not only strengthens our understanding of the ecology of subtidal forests, but will also improve the predictive power of further research in this system. / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2005.

Continuous culture fermentation (CCF) was used to test the hypotheses that: marine microalgae (MA) and macroalgae (seaweeds) alter rumen microbial metabolism; MA types differ in abilities to provide rumen escape n-3 polyunsaturated fatty acids (PUFA); and algae have the potential to reduce enteric methane emission. The CCF system of Teather and Sauer (1988) was modified to reduce clogging, refrigerate effluent, and allow for determination of gas production. The CCF systems were inoculated with pooled rumen fluid from 4 cows. Total mixed ration was fed at the rate of 30 g DM d-1. Temperature was maintained at 39 oC, and buffered with artificial saliva to maintain pH 6.2. Response variables were measured from effluent digesta (fatty acids, NH4+-N, digestibility), fermentor contents (CCF density, volatile fatty acids), and the gas phase (CO2, CH4). The experimental design for MA testing was a 3**3 factorial. Treatments consisted of heterotrophic and photoautotrophic MA as well as a 1:1 blend with protection levels of zero, 33 and 50 % of encapsulation (w/w), and fluid turnover rates of 5, 7.5, and 10 % h-1. The seaweed treatments consisted of a PEI shoreweed mix containing Laminaria longicruris and Fucus vesiculosus tested as a component of the mix, and Chondrus crispus and Furcellaria fastigiata tested individually. The design for seaweed testing was an unbalanced 5*5 Latin square. The heterotrophic MA destabilized the digesta mat while the autotroph improved stability. Biohydrogenation was extensive for C18 FA in the basal ration (> 90 %) and less for C22:6n3 (75 %) from the heterotroph and C20:5n3 (60 %) from the photoautotroph. The recovery of PUFA was improved by encapsulation, however PUFA in the MA were not greatly affected and digestibility was improved by turnover rate. Seaweeds had no effect on CCF stability, however they reduced CH4 production without reduction in OM digestibility. The heterotroph reduced overall fermentation resulting in diminished density and volatile fatty acids and NH4+-N concentrations. Seaweed supplementation decreased NH4+-N, CO2 and CH4 production, and increased density.

The oceans represent a wealth of biological diversity where many species remain to be discovered and described. Among seaweeds, a paucity of morphological features by which to differentiate species means that many genera harbour overlooked or cryptic species. Fucus, Porphyra and Ulva are three common genera of marine intertidal algae and all include species that are particularly difficult to distinguish morphologically. DNA barcoding has been championed as a revolutionary tool for species identification and discovery and applying this tool to algae was a logical step due to the difficulty of morphological identification of many algal species. This thesis is part of a significant initiative aimed at identification and discovery of all species of seaweeds in Canadian waters, using a DNA barcoding approach. The original concept of DNA barcoding relied on comparing the 5’ region of the mitochondrial cytochrome c oxidase 1 (COI-5P) gene among animal species. In this study, DNA barcoding with COI-5P was applied to the brown algal genus Fucus and worked as well as any other marker to assign morphologies to known species. The DNA barcoding results also uncovered substantial phenotypic diversity in Pacific F. distichus. Results were confirmed by comparison with sequences of the nuclear internal transcribed spacer region (ITS). For Porphyra, COI-5P DNA barcoding was compared with species identification using the chloroplast large rubisco subunit (rbcL) and the Universal Plastid Amplicon (UPA) in a floristic survey of Canadian Porphyra species. Two new species were discovered and described (Porphyra corallicola and Porphyra peggicovensis), and P. cuneiformis was synonymized with P. amplissima. The COI-5P emerged as the best marker for species discrimination despite difficulties with primer universality. To aid in choosing a marker for DNA barcoding for green algae, the universality and species discriminatory power of the rubisco large subunit (rbcL) (considering the 5’ and 3’ fragments independently), the UPA, the D2/D3 region of the nuclear large ribosomal subunit (LSU-D2/D3) and the ITS were evaluated. While the rbcL-3P highlighted several cryptic species, and worked well to distinguish Ulva species, more research is needed to recommend a marker for DNA barcoding generally in marine green macroalgae.