The cycling of arsenic in the marine photosynthetic plants and algae was examined by analysing total arsenic concentrations and arsenic species in selected marine photosynthetic organisms from the south-east coast, NSW, Australia. A range of elements required for metabolism in photosynthetic organisms were also analysed to determine if any relationship between these elements and arsenic concentrations occurred. Organisms were selected from salt marsh and mangrove ecosystems, marine inter-tidal and estuarine environments, and two species of marine phytoplankton cultured, to represent the different marine environments that primary producers inhabit. Organisms selected were compared to species within their own environment and then a comparison made between the varying ecosystems. In the salt marsh and mangrove ecosystems, the leaves of four species, the mangrove Avicennia marina, the samphire Sarcocornia quinqueflora, the seablight Suaeda australis, and the seagrass Posidonia australis were sampled from three locations from the south-east coast of NSW using nested sampling. Mean total arsenic concentrations (mean � sd) dry mass for all locations were A. marina (0.38 � 0.18 �g g-1 to 1.2 � 0.7 �g g-1), S. quinqueflora (0.13 � 0.06 �g g-1 to 0.46 � 0.22 �g g-1), S. australis (0.03 � 0.06 �g g-1 to 0.05 � 0.03 �g g-1)and P. australis (0.34 � 0.10 �g g-1 to 0.65 � 0.26 �g g-1). Arsenic concentrations were significantly different between species and locations but were consistently low compared to marine macroalgae species. Significant relationships between As and Fe concentrations for A. marina, S. quinqueflora and P. australis and negative relationship between As and Zn concentrations for S. quinqueflora could partially explain arsenic concentrations in these species. No relationship between As and P concentrations were found in this study. All terrestrial species contained predominantly inorganic arsenic in the water extractable and residue fractions with minor concentrations of DMA in the water-soluble fraction. P. australis also contained dimethylated glycerol and phosphate arsenoriboses. The presence of arsenobetaine, arsenocholine and trimethylated glycerol arsonioribose is most likely due to the presence of epiphytes on fronds on P. australis. In contrast, macroalgae contained higher total arsenic concentrations compared to marine terrestrial angiosperms. Total arsenic concentrations also varied between classes of algae: red macroalgae 4.3 �g g-1 to 24.7 �g g-1, green macroalgae 8.0 �g g-1 to 11.0 �g g-1 and blue green algae 10.4 �g g-1 and 18.4 �g g-1. No significant relations were found between As concentrations and concentrations of Fe, Co, Cu, Mn, Mo, Mg, P and Zn concentrations, elements that are required by macroalgae for photosynthesis and growth. Distinct differences between algal classes were found for the proportion of arsenic species present in the lipid and water-soluble fractions, with green algae having a higher proportion of As in lipids than red or estuarine algae. Acid hydrolysis of the lipid extract revealed DMA, glycerol arsenoribose and TMA based arsenolipids. Within water-soluble extracts, red and blue-green algae contained a greater proportion of arsenic as inorganic and simple methylated arsenic species compared to green algae, which contained predominantly glycerol arsenoribose. Arsenobetaine, arsenocholine and tetramethylarsonium was also present in water-soluble extracts but is not normally identified with macroalgae and is again likely due to the presence of attached epiphytes. Residue extracts contained predominantly inorganic arsenic, most likely associated with insoluble constituents of the cell. Mean arsenic concentrations in the green microalgae Dunaliella tertiolecta were 13.3 �g g-1 to 14.5 �g g-1, which is similar to arsenic concentrations found in green macroalgae in this study. Diatom Phaeodactylum tricornutum arsenic concentrations were 1.62 �g g-1 to 2.08 �g g-1. Varying the orthophosphate concentrations had little effect on arsenic uptake of microalgae. D. tertiolecta and P. tricornutum metabolised arsenic, forming simple methylated arsenic species and arsenic riboses. The ratio of phosphate to glycerol arsenoriboses was higher than that normally found in green macroalgae. The hydrolysed lipid fraction contained DMA arsenolipid (16-96%) with minor proportions of phosphate arsenoribose (4-23%). D. tertiolecta at f/10 phosphate concentration, however, contained glycerol arsenoribose and another arsenic lipid with similar retention as TMAO as well as DMA. The similarities between arsenic species in the water-soluble hydrolysed lipids and water-soluble extracts, especially for P. tricornutum, suggests that cells readily bind arsenic within lipids, either for membrane structure or storage, releasing arsenic species into the cytosol as degradation of lipids occurs. Inorganic arsenic was sequestered into insoluble components of the cell. Arsenic species present in D. tertiolecta at lower phosphate concentrations (f/10) were different to other phosphate concentrations (f/2, f/5), and require further investigation to determine whether this is a species-specific response as a result of phosphate deficiency. Although there are similarities in arsenic concentrations and arsenic species in marine photosynthetic organisms, it is evident that response to environmental concentrations of arsenic in uncontaminated environments is dependent on the mode of transfer from the environment, the influence of other elements in arsenic uptake and the ability of the organism to metabolise and sequester inorganic arsenic within the cell. It is not scientifically sound to generalise on arsenic metabolism in �marine plants� when species and the ecosystem in which they exist may influence the transformation of arsenic in higher marine organisms. There is no evidence to suggest that angiosperms produce AB as arsenic is mostly present as inorganic As, with little or no arsenic present in the lipids. However, marine macro- and microalgae both contain lipids with arsenic moieties that may be precursors for AB transformation. Specifically, the presence of TMA and dimethylated arsenoribose based arsenolipids both can transform to AB via intermediates previously identified in marine organisms. Further identification and characterization of As containing lipids is required.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19781号 / 農博第2177号 / 新制||農||1041(附属図書館) / 学位論文||H28||N4997(農学部図書室) / 32817 / 京都大学大学院農学研究科農学専攻 / (主査)教授 白岩 立彦, 教授 奥本 裕, 教授 稲村 達也 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Climate change models predict an increase in frequency and amplitude of extreme weather events, including heat waves. To better predict how the composition and distribution of plant assemblages might respond to these changes in temperature, it is important to understand how species currently respond to these extremes. Photosynthetic thermal tolerance (T25)and photosynthetic recovery (RT25) were quantified in 27 species. We also studied the relationships between T25, RT25 and leaf mass per area (LMA). Leaf temperature was also monitored in the field. Leaves used in this study were collected from two distinct environments representing desert and montane plant assemblages. T25 and RT25 were measured using a chlorophyll fluorescence protocol incorporating sub-saturating light and short duration heat stress. Mean T25and LMA were significantly different between environments. Mean RT25 was not significantly different between environments. There was a positive relationship between T25 and LMA in both environments. The ability to recover from heat stress does not differ between two biomes that experience vastly different mean maximum temperatures during the summer months. LMA is a predictive leaf trait for thermal tolerance.

Η εκτίμηση της παραγωγικότητας των χερσαίων οικοσυστημάτων προϋποθέτει τη δημιουργία αξιόπιστων μοντέλων παραγωγικότητας. Τα μοντέλα παραγωγικότητας τροφοδοτούνται με μια σειρά βιοτικών (φωτοσυνθετική ταχύτητα, συγκέντρωση χλωροφύλλης, ειδική μάζα φύλλου) και αβιοτικών παραμέτρων (θερμοκρασία, ένταση φωτός, βροχόπτωση) των φυτικών ειδών και του περιβάλλοντος. Μία από τις σημαντικότερες βιοτικές παραμέτρους αποτελεί η μέγιστη φωτοσυνθετική ταχύτητα κάτω από κορεσμένες εντάσεις φωτός, σε φυσιολογικές συγκεντρώσεις CO2 και στις επικρατούσες θερμοκρασίες (Asat). Η μέτρηση της Asat στο πεδίο με τις κλασσικές μεθόδους (αναλυτής αερίων) είναι επίπονη και χρονοβόρος διαδικασία. Για το λόγο αυτό νέοι τρόποι υπολογισμού της Asat προτείνονται. Στην παρούσα εργασία διερευνήθηκε η δυνατότητα εκτίμησης της Asat ορισμένων μεσογειακών φυτών μέσω της ανάλυσης της ταχείας φάσης ανόδου του φθορισμού της χλωροφύλλης (JIP-test). Για το σκοπό αυτό χρησιμοποιήθηκαν τα ετήσια είδη Malva sylvestris και Capparis spinosa, το φυλλοβόλο είδος Cercis siliquastrum, το ημιφυλλοβόλο είδος Phlomis fruticosa, και τα σκληρόφυλλα είδη Nerium oleander, Ceratonia siliqua και Ligustrum japonicum. Οι μετρήσεις της Asat πραγματοποιήθηκαν με τη χρήση αναλυτή αερίων ανοικτού τύπου (LI-6400, LICOR), ενώ για τη μέτρηση της ταχείας φάσης ανόδου του φθορισμού χρησιμοποιήθηκε φθορισμόμετρο υψηλής χρονικής ανάλυσης (HandyPEA, Hansatech). Οι μετρήσεις πραγματοποιήθηκαν σε εποχιακή βάση. Σύμφωνα με τα αποτελέσματα των πειραμάτων μας, δεν βρέθηκε κάποια παράμετρος του JIP-test που μπορεί να χρησιμοποιηθεί ως γενικευμένος δείκτης της Asat, αντίθετα η Asat εμφάνισε πολύ καλή συσχέτιση με τη στοματική αγωγιμότητα. Εντούτοις, στα σκληρόφυλλα είδη και το ημιφυλλοβόλο είδος βρέθηκε καλή συσχέτιση μεταξύ της Asat και των δεικτών ψΕ0, δR0 και φR0 για τα χειμερινή ομάδα μετρήσεων. Η δυσμενέστερη περίοδος για τα πολυετή είδη φαίνεται πως είναι το καλοκαίρι. Τέλος, ο δείκτης VK/VJ μπορεί να υποδείξει τις κύριες καταπονητικές περιόδους. / The evaluation of the productivity of terrestrial ecosystems presupposes the creation of reliable productivity models. The productivity models are supplied with a series of biotic (photosynthetic rate, chlorophyll concentration, specific leaf mass) and abiotic parameters (temperature, light intensity, rainfall) of the plant species and of the environment. One of the most important biotic parameters is the maximum photosynthetic rate under saturated light intensities, under ambient CO2 concetration and under the prevailing temperatures (Asat). The measurement of Asat under field conditions using the traditional methods (gas analyzer) is a laborious and time consuming process. For this reason new methods of Asat calculation are suggested. In the present study the possibility of Asat estimation in some Mediterranean species with the use of the fast chlorophyll fluorescence transient (JIP-test) has been examined. For this purpose, the annual species Malva sylvestris and Capparis spinosa, the deciduous species Cercis siliquastrum, the semi-deciduous species Phlomis fruticosa, and the sclerophyllous species Nerium oleander, Ceratonia siliqua και Ligustrum japonicum have been used. The Asat measurements have been carried out with the use of an open gas exchange analyzer (LI-6400, LICOR), while for the measurement of the fast chlorophyll fluorescence transient a high-time resolution fluorometer (HandyPEA, Hansatech) has been used. The measurements were carried out on a seasonal basis. According to the results of our experiments, no JIP-test parameter has shown to act as a generalized index of Asat, while Asat has shown a very good correlation with stomatal conductance. However, at the sclerophyllous and the semi-deciduous species, a good correlation between Asat and ψΕ0, δR0 και φR0 indices has been shown for the winter team. The most adverse period of the year for the perennial species is summer. Finally, VK/VJ index is indicative of the most stressful periods for our species.

This study investigated the use of optical remote sensing for estimating leaf and canopy scale light use efficiency (LUE) and carbon exchange. In addition, a new leaf level model capable of predicting dynamic changes in apparent reflectance due to chlorophyll fluorescence was developed. A leaf level study was conducted to assess the applicability of passive remote sensing as a tool to measure the reduction, and the subsequent recovery, of photosynthetic efficiency during the weeks following transplantation. Spectral data were collected on newly planted saplings for a period of 8 weeks, as well as gas exchange measurements of LUE and PAM fluorescence measurements. A set of spectral indices, including the Photochemical Reflectance Index (PRI), were calculated from the reflectance measurements. A marked depression in photosynthetic rate occurred in the weeks after outplanting followed by a gradual increase, with recovery occurring in the later stages of the experimental period. As with photosynthetic rate, there was a marked trend in PRI values over the study period but no trend was observed in chlorophyll based indices. The study demonstrated that hyperspectral remote sensing has the potential to be a useful tool in the detection and monitoring of the dynamic effects of transplant shock. Relationships between hyperspectral reflectance indices, airborne carbon exchange measurements and satellite observations of ground cover were then explored across a heterogeneous Arctic landscape. Measurements were collected during August 2008, using the University of Edinburgh’s research aircraft, from an Arctic forest tundra zone in northern Finland as part of the Arctic Biosphere Atmosphere Coupling at Multiple Scales (ABACUS) study. Surface fluxes of CO2 were calculated using the eddy covariance method from airborne data that were collected from the same platform as hyperspectral reflectance measurements. Airborne CO2 fluxes were compared to MODIS vegetation indices. In addition, LUE was estimated from airborne flux data and compared to airborne measurements of PRI. There were no significant relationships between MODIS vegetation indices and airborne flux observations. There were weak to moderate (R2 = 0.4 in both cases) correlations between PRI and LUE and between PRI and incident radiation. A new coupled physiological radiative transfer model that predicts changes in the apparent reflectance of a leaf, due to chlorophyll fluorescence, was developed. The model relates a physically observable quantity, chlorophyll fluorescence, to the sub leaf level processes that cause the emission. An understanding of the dynamics of the processes that control fluorescence emission on multiple timescales should aid in the interpretation of this complex signal. A Markov Chain Monte Carlo (MCMC) algorithm was used to optimise biochemical model parameters by fitting model simulations of transient chlorophyll fluorescence to measured reflectance spectra. The model was then validated against an independent data set. The model was developed as a precursor to a full canopy scheme. To scale to the canopy and to use the model on trans-seasonal time scales, the effects of temperature and photoinhibition on the model biochemistry needs to be taken into account, and a full canopy radiative transfer scheme, such as FluorMOD, must be developed.

Woody plant expansion has been documented for decades in many different ecosystems, often due to anthropogenic disturbances to the environment and yielding vast changes in ecosystem functioning. While causes and consequences of woody expansion have been well documented, few studies have investigated functional traits of woody species that promote rapid expansion in range. My objective was to determine if hydraulic efficiency confers enhanced photosynthetic efficiency so that functional traits representing light and water use may be possible mechanisms facilitating woody encroachment into grasslands and forest understories. I quantified leaf-level light environment, photosynthetic activity, and hydraulic characteristics of three sympatric broadleaf evergreens of varying leaf life span (Ilex opaca, Kalmia latifolia, and Myrica cerifera) in a deciduous forest understory to understand seasonal intra- and interspecific ranges of broadleaf evergreen physiology. Additionally, I investigated the effects of age on physiological efficiency of M. cerifera across a chronosequence (i.e., space for time substitution) of shrub thicket development in order to understand possible age-related physiological mechanisms facilitating shrub expansion. Lastly, I determined functional traits and resulting physiology that contribute to rapid expansion and thicket formation of an invasive, deciduous, N-fixing shrub, Elaeagnus umbellata, and a native, evergreen, N-fixing shrub M. cerifera. When compared to co-occurring evergreen species, electron transport rate (ETR) of M. cerifera was nearly double that of I. opaca or K. latifolia in summer. Photosynthetic capacity was positively related to hydraulic capacity among understory evergreens. Furthermore, photosynthetic and hydraulic efficiency of M. cerifera remained consistent despite considerable differences in thicket age and development. Both similar and contrasting functional traits of E. umbellata and M. cerifera allowed for enhanced light capture and water movement, and reductions in subcanopy light penetration. Enhanced hydraulic and photosynthetic efficiency relative to co-occurring species contributes to rapid range expansion and thicket formation by promoting enhanced productivity and limiting successful colonization of other species. My results indicate that there may be suites of functional traits linked to expansive success and thicket-formation, yet differences in functional traits between native and invasive species represent alternative strategies leading to rapid growth and thicketization.

Phytoplankton Chlorophyll a (CHLa), total protein, colloidal carbohydrates, storage carbohydrates and taxonomic pigment relationships were studied in two cyanophytes (Microcystis aeruginosa and Synnechococcus elongatus), two chlorophytes (Dunaliella tertiolecta and Scenedesmus quadricauda), one cryptophyte (Rhodomonas salina), two diatoms (Cyclotella meneghiniana and Thalassiosira weissflogii) and one dinophyte (Amphidinium carterae) to assess if algal biomass could be expressed in other indices than just chlorophyll a alone. Protein and carbohydrates are more useful currencies for expressing algal biomass, with respect to energy flow amongst trophic levels. These phytoplankton were grown at low light (LL = 37 (So(Bmol photons m-2 s-1), medium light (ML = 70-75 (So(Bmol photons m-2 s-1), and high light (HL= 200 (So(Bmol photons m-2 s-1). / Even though pigment per cell increased with increasing light intensity, statistically light had very little effect on the CHL a : taxonomic marker pigment ratios, as they covaried in the same way. Protein, colloidal carbohydrates and storage carbohydrates per cell all increased with increasing light intensity, but they did not covary with CHLa. Statistical data showed that light intensity had a more noticeable effect on protein: CHL a, colloidal carbohydrate: CHLa, storage CHO: CHLa, therefore a general mathematical expression for these relationships cannot be generated. This study showed that light intensity does have an influence on these biomass indices, therefore, seasonal and latitudinal formulas may be required for meaningful algal biomass estimation. However, more studies are needed if that goal is to be realized. / While studying the effects of light intensity on algal pigment content and concentration, a new pigment was isolated from a cyanophyte (Scytonema hofmanii) growing between 300-1800 (So(Bmol photons¨m-2¨s-1 and from samples collected in areas of the Florida Everglades. This pigment was characterized and structurally determined to possess indolic and phenolic subunits that are characteristic of scytonemin and its derivatives. In addition, the pigment has a ketamine functionality which gives it its unique polarity and spectral properties. Based on the ultra violet/visible absorbance data, this pigment was postulated to be protecting the chlorophyll a and cytochrome Soret bands as well as a and (Sb (Bbands of the cytochromes (e.g. cytc-562) in the photosynthetic unit. / by Cidya Grant. / Thesis (Ph.D.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

O objetivo principal deste trabalho foi avaliar o óleo produzido por cianobactérias como matéria-prima lipídica para sintetisar biodiesel pela rota etílica empregando catalisadores heterogêneos. Cinco linhagens de cianobactérias não produtoras de toxinas: Microcystis aeruginosa NPCD-1, Synechococcus sp. PCC7942, Chlorogloea sp. CENA170, Leptolyngbya sp. CENA104 e Trichormus sp. CENA77 foram inicialmente cultivadas e avaliadas, tomando por base parâmetros como: produtividade de biomassa celular, teor de lipídeo e composição em ácidos graxos. Os valores mais elevados de produtividade celular e de lipídeo foram obtidos para as linhagens M. aeruginosa NPCD-1, Trichormus sp. CENA77 e Synechococcus sp. PCC7942. As matérias-primas lipídicas oriundas das linhagens selecionadas foram ainda caracterizadas quanto as propriedades reológicas (viscosidade), térmicas (termogravimetria) e químicas (espectroscopia na região de infravermelho). Na etapa seguinte, as condições de cultivo das linhagens foram estudadas e otimizadas por meio de um planejamento fatorial avaliando as variáveis intensidade luminosa (50 a 150 ?mol m-2s-1) e concentração de Na2CO3 (0,5 a 1,5 g/L), considerando como variáveis resposta a produtividade celular e o teor de lipídeo. A análise estatística indicou que a intensidade de luz influenciou positivamente os valores de produtividade celular para todas as linhagens estudadas, enquanto a concentração de Na2CO3 influenciou negativamente apenas no cultivo da linhagem M. aeruginosa NPCD-1. Com relação à variável teor de lipídeo, para a linhagem M. aeruginosa NPCD-1 nenhuma variável apresentou significância dentro da faixa estudada. No entanto, para as outras linhagens, o emprego das variáveis estudadas nos níveis mais altos implicou valores mais elevados para o teor de lipídeo. Definidas as condições ótimas de cultivo, o trabalho foi direcionado para execução da reação de interesse do projeto, empregando dois catalisadores heterogêneos de comprovada potencialidade: óxido de nióbio impregnado com sódio (químico) e Novozym 435® (bioquímico). Os resultados obtidos demonstraram que ambos os catalisadores atuaram de forma eficiente, convertendo os ácidos graxos em seus respectivos ésteres de etila. Entretanto, a qualidade da biomassa (índice de acidez e presença de pigmentos) interferiu a atuação dos catalisadores de maneira diferenciada. Enquanto o catalisador químico foi sensível à presença de níveis elevados de acidez, como constatado no óleo de Trichormus sp. CENA77, o catalisador bioquímico pode ter adsorvido os pigmentos presentes em maior quantidade nessa matéria-prima, reduzindo sua atividade catalítica. Desta forma, com exceção do biodiesel dessa matéria-prima lipídica, parâmetros, tais como número de cetano, ponto de entupimento de filtro a frio, índice de saponificação e índice de iodo, foram estimados por modelos teóricos, visando à predição da qualidade do biodiesel obtido dos diferentes óleos de acordo com as especificações estabelecidas pelas normas oficiais. Do ponto de vista geral, os resultados obtidos neste trabalho foram promissores e demonstraram a potencialidade do uso de cianobactérias como fonte de matéria-prima lipídica na síntese de biodiesel. As amostras de biodiesel das biomassas lipídicas de Microcystis aeruginosa NPCD-1 e Synechococcus sp. PCC7942 obtidas pela catálise heterogênea química atenderam as especificações estabelecidas na ANP como biocombustível. / The main goal of this study was to evaluate the lipid extracted from cyanobacteria as feedstock source for the synthesis of biodiesel using heterogeneous catalysis and ethanol as acyl acceptor. Five cyanobacterial non-microcystin producer strains: Microcystis aeruginosa NPCD-1; Synechococcus sp. PCC7942; Chlorogloea CENA170; Leptolyngbya CENA104 and Trichormus sp. CENA77 were cultivated and evaluated taking into account the biomass productivity, lipid content and fatty acid composition. Results indicated that M. aeruginosa NPCD-1, Trichormus sp. CENA77 and Synechococcus sp. PCC7942 gave the best set of parameters and were selected for further characterization using analytical techniques, including: viscosimetry, thermogravimetry and infrared spectroscopy. Following this, the cultivation conditions were studied and optimized using a factorial design, taking into consideration as independent variables light irradiance (50 to 150 ?mol m-2s-1) and concentration of Na2CO3 (0.5 to 1.5 g/L) as a carbon source. Cell productivity and lipid content were taking as response variables. For all strains, the most important factor was the light irradiance, since it presented a significant effect for all responses. Depend on the cyanobacteria strain, the concentration of Na2CO3 was found to have either positive or negative influence on the response variables. While for the M. aeruginosa NPCD-1 the presence of the Na2CO3 in the culture medium negative affected both cell productivity and lipid level, for the other strains high levels of Na2CO3 increase the lipid levels. After establishing the optimum cultivation conditions the experimental work was directed towards to perform the reaction of interest, using cyanobacterial feedstocks and two heterogeneous catalysts: chemical (niobium oxide impregnated with sodium) and biochemical (Novozym 435®). The dataset obtained demonstrated that the formation of ethyl esters from the feedstocks was feasible for the tested catalysts. Both catalysts were efficient in converting all fatty acids present in the feedstocks into the corresponding ethyl esters; however the chemical catalyst gave higher conversion than the biochemical one. The lower quality of the Trichormus sp. CENA77 feedstock strong affected the performance of the catalysts in a different way. While the chemical catalyst was sensitive to high acidity level verified in this microbial oil, the biocatalyst performance was influenced by the presence of pigments which was adsorbed on the biocatalyst matrix reducing its catalytic activity. Except for this oil, parameters such as cetane number, cold filter plugging point, saponification number and iodine value were estimated by theoretical models to predict the quality of biodiesel according to the specifications established by official standards. The results obtained in this study were promising and demonstrated the potential of using cyanobacteria as a feedstock source in the biodiesel synthesis. The lipid biomass from M. aeruginosa NPCD-1 and Synechococcus sp. PCC7942 originated biodiesel samples with appropriate characteristics to be used as fuel that are in accordance with specifications recommended by ANP.

Cianobactérias são micro-organismos procarióticos fotoautotróficos que apresentam ampla variedade morfológica e metabólica, o que favorece sua colonização nos mais diversos tipos de ambientes. Essa versatilidade favorece a sua utilização em inúmeras aplicações biotecnológicas em áreas como agricultura, energia, nutrição e tratamento de efluentes. Com o aumento da demanda energética e de alimentos, as cianobactérias são consideradas alternativas mais sustentáveis para a biossíntese de produtos de interesse industrial. Nesse contexto, o objetivo deste estudo foi avaliar o crescimento de cianobactérias em meios suplementados com vinhaça e seus efeitos na produção de lipídios e na composição de ácidos graxos, visando a produção de biodiesel. Para tanto, onze linhagens de cianobactérias isoladas de amostras de água coletadas em rios da Amazônia foram identificadas morfologicamente e geneticamente como pertencentes à quatro ordens - Nostocales, Chroococciodipsidales, Synecoccocales e Oscillatoriales. Essas linhagens tiveram o seu crescimento avaliado em meios de cultivo suplementados com vinhaça (1, 2,5, 5 e 10% v/v) e em vinhaça diluída em água ultrapura (2,5, 5 e 10% v/v). Todas as linhagens foram capazes de crescer nas concentrações testadas, porém, nas concentrações mais elevadas de vinhaça, observou-se a inibição do crescimento e/ou o aumento da proliferação de contaminantes heterotróficos. Nas diluições de vinhaça em água ultrapura, nenhuma linhagem apresentou crescimento. Duas linhagens foram selecionadas para análises subsequentes devido ao rápido crescimento (Planktothrix mougeotii CMAA1564) e ao perfil de ácidos graxos favoráveis à produção de biodiesel (Amazoninema brasiliense CMAA1602, gênero inédito). Essas linhagens tiveram seu crescimento investigado nos meios BG11, BG11+1% e BG11+2,5% de vinhaça utilizando os métodos gravimétrico (biomassa seca) e espectrofométrico (densidade ótica - DO680nm e DO750nm), para a identificação das fases de crescimento. As maiores taxas de produtividade lipídica e de biomassa foram observadas nas biomassas coletadas na fase log em meio suplementado com vinhaça a 1%, com destaque para P. mougeotii CMAA1564 (3,18 e 35,87 mg L-1 dia-1, respectivamente). A análise do perfil de ácidos graxos das frações lipídicas mostrou a predominância dos ácidos graxos saturados e monoinsaturados nos óleos das biomassas cultivadas em meio com vinhaça, sendo majoritários os ácidos palmítico, palmitoleico, oleico e alfa-linolênico. A partir da composição de ácidos graxos das frações lipídicas foi possível estimar 11 parâmetros de qualidade do biodiesel derivado dessa matéria-prima lipídica. A maioria das propriedades avaliadas estavam de acordo com as especificações de qualidade do biodiesel estabelecidas na legislação nacional e internacional, com exceção para a viscosidade cinemática que apresentou valores inferiores. Esses resultados são promissores visto a oportunidade de exploração da biodiversidade de cianobactérias ainda pouco estudada para fins biotecnológicos. Essa pesquisa demonstra a viabilidade de utilização do conteúdo lipídico desses organismos como matéria-prima lipídica alternativa para a produção de biodiesel / Cyanobacteria are photoautotrophic prokaryotes that show a wide morphological and metabolic variety, which favors the colonization of the most diverse types of environments. This versatility reflects in its numerous biotechnological applications in areas such as agriculture, energy, nutrition and effluent treatment. With the increasing in energy and food demand, cyanobacteria are considered a more sustainable alternative for the biosynthesis of products of industrial interest. In this context, the aim of this study was to evaluate the cyanobacteria growth in media supplemented with vinasse and its effect on lipid production and fatty acid composition, with focus on biodiesel production. So, eleven cyanobacterial strains from water samples from Amazonian rivers were morphologically and genetically identified as belonging to four orders - Nostocales, Chroococciodipsidales, Synecoccocales e Oscillatoriales. These strains had their growth evaluated in culture media supplemented with vinasse (1, 2,5, 5 and 10% v/v) and in vinasse diluted in ultrapure water (2,5, 5 and 10% v/v). All strains were able to grow at the concentrations tested, however, at higher vinasse concentrations, growth inhibition and/or higher heterotrophic contaminants proliferation was observed. In vinasse diluted in ultrapure water, none of them were able to grow. Two cyanobacterial strains were selected for subsequent analysis due to rapid growth (Planktothrix mougeotii CMAA1564) and favorable fatty acid profile for biodiesel production (Amazoninema brasiliense CMAA1602, a new genus). Then, these strains had their gowth investigated in the media BG11, BG11+1% and BG11+2,5% of vinasse using the gravimetric (dry biomass) and spectrophotometric (optical density - OD680nm e OD750nm) methods, for growth phases identification. The highest lipid and biomass productivities were observed in the biomass collected in the log phase in medium supplemented with 1% of vinasse, wtith the highest values observed for the P. mougeotii CMAA1564 (3,18 e 35,87 mg L-1 dia-1, respectively). The fatty acid profile of the lipid fraction showed the predominance of saturated and monounsaturated fatty acids in the oils of biomass grown in vinasse medium, with palmitic, palmitoleic, oleic and alpha-linolenic acids being the majority. From the fatty acid composition of the oils, it was possible to estimate eleven quality parameters of the biodiesel derived from these lipid feedstocks. Most of the properties evaluated werein accordance with the biodiesel quality specification estabilished in the national and international legislation, except for the kinematic viscosity that presented lower values. These results are promising given the opportunity for exploiting the underestimated cyanobacteria diversity for biotechnological purposes. This research shows the feasibility of using the lipid content of these organisms as an alternative lipid feedstock for biodiesel production

O objetivo principal deste trabalho foi avaliar o óleo produzido por cianobactérias como matéria-prima lipídica para sintetisar biodiesel pela rota etílica empregando catalisadores heterogêneos. Cinco linhagens de cianobactérias não produtoras de toxinas: Microcystis aeruginosa NPCD-1, Synechococcus sp. PCC7942, Chlorogloea sp. CENA170, Leptolyngbya sp. CENA104 e Trichormus sp. CENA77 foram inicialmente cultivadas e avaliadas, tomando por base parâmetros como: produtividade de biomassa celular, teor de lipídeo e composição em ácidos graxos. Os valores mais elevados de produtividade celular e de lipídeo foram obtidos para as linhagens M. aeruginosa NPCD-1, Trichormus sp. CENA77 e Synechococcus sp. PCC7942. As matérias-primas lipídicas oriundas das linhagens selecionadas foram ainda caracterizadas quanto as propriedades reológicas (viscosidade), térmicas (termogravimetria) e químicas (espectroscopia na região de infravermelho). Na etapa seguinte, as condições de cultivo das linhagens foram estudadas e otimizadas por meio de um planejamento fatorial avaliando as variáveis intensidade luminosa (50 a 150 ?mol m-2s-1) e concentração de Na2CO3 (0,5 a 1,5 g/L), considerando como variáveis resposta a produtividade celular e o teor de lipídeo. A análise estatística indicou que a intensidade de luz influenciou positivamente os valores de produtividade celular para todas as linhagens estudadas, enquanto a concentração de Na2CO3 influenciou negativamente apenas no cultivo da linhagem M. aeruginosa NPCD-1. Com relação à variável teor de lipídeo, para a linhagem M. aeruginosa NPCD-1 nenhuma variável apresentou significância dentro da faixa estudada. No entanto, para as outras linhagens, o emprego das variáveis estudadas nos níveis mais altos implicou valores mais elevados para o teor de lipídeo. Definidas as condições ótimas de cultivo, o trabalho foi direcionado para execução da reação de interesse do projeto, empregando dois catalisadores heterogêneos de comprovada potencialidade: óxido de nióbio impregnado com sódio (químico) e Novozym 435® (bioquímico). Os resultados obtidos demonstraram que ambos os catalisadores atuaram de forma eficiente, convertendo os ácidos graxos em seus respectivos ésteres de etila. Entretanto, a qualidade da biomassa (índice de acidez e presença de pigmentos) interferiu a atuação dos catalisadores de maneira diferenciada. Enquanto o catalisador químico foi sensível à presença de níveis elevados de acidez, como constatado no óleo de Trichormus sp. CENA77, o catalisador bioquímico pode ter adsorvido os pigmentos presentes em maior quantidade nessa matéria-prima, reduzindo sua atividade catalítica. Desta forma, com exceção do biodiesel dessa matéria-prima lipídica, parâmetros, tais como número de cetano, ponto de entupimento de filtro a frio, índice de saponificação e índice de iodo, foram estimados por modelos teóricos, visando à predição da qualidade do biodiesel obtido dos diferentes óleos de acordo com as especificações estabelecidas pelas normas oficiais. Do ponto de vista geral, os resultados obtidos neste trabalho foram promissores e demonstraram a potencialidade do uso de cianobactérias como fonte de matéria-prima lipídica na síntese de biodiesel. As amostras de biodiesel das biomassas lipídicas de Microcystis aeruginosa NPCD-1 e Synechococcus sp. PCC7942 obtidas pela catálise heterogênea química atenderam as especificações estabelecidas na ANP como biocombustível. / The main goal of this study was to evaluate the lipid extracted from cyanobacteria as feedstock source for the synthesis of biodiesel using heterogeneous catalysis and ethanol as acyl acceptor. Five cyanobacterial non-microcystin producer strains: Microcystis aeruginosa NPCD-1; Synechococcus sp. PCC7942; Chlorogloea CENA170; Leptolyngbya CENA104 and Trichormus sp. CENA77 were cultivated and evaluated taking into account the biomass productivity, lipid content and fatty acid composition. Results indicated that M. aeruginosa NPCD-1, Trichormus sp. CENA77 and Synechococcus sp. PCC7942 gave the best set of parameters and were selected for further characterization using analytical techniques, including: viscosimetry, thermogravimetry and infrared spectroscopy. Following this, the cultivation conditions were studied and optimized using a factorial design, taking into consideration as independent variables light irradiance (50 to 150 ?mol m-2s-1) and concentration of Na2CO3 (0.5 to 1.5 g/L) as a carbon source. Cell productivity and lipid content were taking as response variables. For all strains, the most important factor was the light irradiance, since it presented a significant effect for all responses. Depend on the cyanobacteria strain, the concentration of Na2CO3 was found to have either positive or negative influence on the response variables. While for the M. aeruginosa NPCD-1 the presence of the Na2CO3 in the culture medium negative affected both cell productivity and lipid level, for the other strains high levels of Na2CO3 increase the lipid levels. After establishing the optimum cultivation conditions the experimental work was directed towards to perform the reaction of interest, using cyanobacterial feedstocks and two heterogeneous catalysts: chemical (niobium oxide impregnated with sodium) and biochemical (Novozym 435®). The dataset obtained demonstrated that the formation of ethyl esters from the feedstocks was feasible for the tested catalysts. Both catalysts were efficient in converting all fatty acids present in the feedstocks into the corresponding ethyl esters; however the chemical catalyst gave higher conversion than the biochemical one. The lower quality of the Trichormus sp. CENA77 feedstock strong affected the performance of the catalysts in a different way. While the chemical catalyst was sensitive to high acidity level verified in this microbial oil, the biocatalyst performance was influenced by the presence of pigments which was adsorbed on the biocatalyst matrix reducing its catalytic activity. Except for this oil, parameters such as cetane number, cold filter plugging point, saponification number and iodine value were estimated by theoretical models to predict the quality of biodiesel according to the specifications established by official standards. The results obtained in this study were promising and demonstrated the potential of using cyanobacteria as a feedstock source in the biodiesel synthesis. The lipid biomass from M. aeruginosa NPCD-1 and Synechococcus sp. PCC7942 originated biodiesel samples with appropriate characteristics to be used as fuel that are in accordance with specifications recommended by ANP.