Orientador: Telma Teixeira Franco / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-21T17:18:31Z (GMT). No. of bitstreams: 1 FrancoAcosta_LilianaMarcela_M.pdf: 2933059 bytes, checksum: f29d16801f9dbfa85c5d787ef30251ad (MD5) Previous issue date: 2012 / Resumo: Em cultivos heterotróficos, fontes orgânicas de carbono são utilizadas para fornecer energia e carbono ao micro-organismo. A glicose e uma das fontes mais utilizadas em cultivos de microalgas, gerando elevadas taxas de crescimento. Outras fontes como frutose, xilose, glicerol, sacarose, arabinose também podem ser utilizadas e a escolha entre essas fontes orgânicas e função principalmente das taxas de crescimento e do custo de aquisição. Visando elevadas produtividades e a redução do custo do cultivo heterotrófico da Chlorella vulgaris, diferentes fontes de carbono orgânico foram avaliadas (glicerol, sacarose, frutose e melaço de cana). Os máximos valores de concentração celular, pH e produtividade, foram para a sacarose hidrolisada na concentração inicial de 20 g.L-1 obtidos apos 122 horas de cultivo (5,3g.L-1; 8.80 e 0.040 g.L-1.h-1, respectivamente) e para o melaço de cana hidrolisado na concentração de 30 g.L-1 obtidos apos 60 horas de cultivo (3,92 g.L-1; 8,55 e 0,059 g.L-1.h-1, respectivamente). Glicerol, sacarose e frutose não foram consumidas pelas células. As melhores concentrações de sacarose hidrolisada (20 g.L-1) e melaço de cana hidrolisado (15 g.L-1) foram utilizados em fermentador de 3 L em regime de batelada alimentada, as velocidades especificas de crescimento para o melaço de cana aumentaram apos cada alimentação desde 0,0512 h-1 ate 0,0644 h-1. No entanto, para a sacarose hidrolisada a velocidade diminuiu de 0,0251 h-1 ate 0,0143 h-1. A concentração de lipídeos foi para a sacarose hidrolisada (23,77 %), e (10,72%) para o melaço de cana. Paralelamente, foram analisadas condições de estocagem da microalga Chlorella vulgaris, em ultrafreezer, empregando-se três criopreservantes: glicerol, metanol e DMSO, nas concentrações de 5 e 10%. Os resultados, apos 270 dias de estocagem, indicam que a microalga Chlorella vulgaris não sobrevive nas condições estabelecidas. No entanto, para uma estocagem de ate 180 dias pode-se empregar 10% de glicerol ou 10% de DMSO, necessitando somente 2 repiques da microalga apos o armazenamento para atingir sua velocidade normal de crescimento (0,2686 d-1), velocidade reportada para a microalga sem armazenamento no ultrafreezer / Abstract: In heterotrophic culture, sources of organic carbon are utilized to give energy and carbon to microorganisms. Glucose is one of the main sources utilized in micro algae culture which produces high growing rates. Another sources such as fructose, xylose, glycerol, saccharose and arabinosa, could also be utilized. The function of growing rates and acquisition costs is precisely to help us to choose the best one between these sources. With the idea of getting high productivities and to reduce costs of heterotrophic crops of Chlorella vulgaris, different sources of organic carbon where studied (glycerol, saccharose, fructose and sugar cane honeydew). The highest values of cellular concentration, pH and productivity, were obtain from hydrolyzed saccharose with an initial concentration of 20 g.L-1 after 122 hours of cultivation (5,3g.L-1; 8.80 y 0.040 g.L-1.h-1, respectively). Glycerol, saccharose y fructose were not consumed by the cells. The best concentrations of hydrolyzed saccharose (20 g.L-1) and hydrolyzed sugar cane honeydew (15 g.L-1) were utilized in 3 L fermenters in feed batch. The growing speed of the sugar cane honeydew increased after each feeding from 0,0512 h-1 to 0,0644 h-1. However, the growing speed for hydrolyzed saccharose decreased from 0,0251 h-1 to 0,0143 h-1. The concentration of fat acids for the hydrolyzed saccharose was 23,77 % and for the sugar cane honeydew was 10,72%. Storage conditions in ultrafreezer for the microalgae Chlorella vulgaris were studied at the same time using three different protectants such as glycerol, methanol and DMSO, all of them in 5% and 10% concentrations. The outcomes obtained after 270 days showed that the Chlorella vulgaris microalgae could not survive with the given conditions. However, 10% of glycerol or DMSO could be used in a 180-day storage and only 2 periodic transfer of the microalgae were needed after the storage to obtain the normal growing speed (0.2686 d- 1), which was the reported speed of the microalgae without ultrafreezer storage / Mestrado / Processos em Tecnologia Química / Mestra em Engenharia Química

Microalgae have been recognized as one of the most promising feedstocks for biofuel production. In the Regional Algal Feedstock Testbed (RAFT) project, scientists and engineers have been working on various topics including improving cultivation strategy, optimizing culture system, developing production models, controlling contamination, and so on. One of the objectives in this project is to improve an algae cultivation model for productivity prediction and techno-economic assessment. The model adopted in this project is the Huesemann Algae Biomass Growth (HABG) model which is based upon strain characteristics obtained from laboratory experiments. However, because the model assumed optimal growth conditions for microalgae, it over-predicted biomass growth significantly when its results were compared to outdoor raceway experimental data. For example, in an attempt to control contamination, culture salinity was raised to a high level. The high salinity may limit growth of contaminants, but it also causes stress on salinity sensitive strains of microalgae. Researchers also lowered nutrient fertilization rates in order to minimize fertilizer input and cost of production. However, this introduced nutrient stress and lowered the growth rate of microalgae. In the raceways used in the RAFT project, shade covered a large fraction of the culture surface when solar angle was low. All of these growth limiting factors were not included in the original model. In this study, salinity stress, nitrogen limitation and shading effect were incorporated into the model. Growth rate reduction due to salinity stress and nitrogen limitation were quantified through laboratory experiments. An innovative concept of nitrogen availability was introduced, which estimates the nitrogen stress factor without measuring intracellular nitrogen. The shading factor was calculated based on solar position during the day and raceway geometry. The modification greatly improved the model accuracy. In addition to HABG model improvements, this study also focused on nutrient application. Several experiments were performed in both indoor and outdoor systems to improve field cultivation practices. The nitrogen experiments provided not only the growth kinetics that improved the growth model, but also demonstrated that high lipid accumulation rate was triggered at different nitrogen stress intensities for different strains. Stress should be applied depending the saturation demand of the final lipid product. In order to quickly evaluate the nitrogen status in the culture, a nitrogen stress index using optical density was proposed. Experiments in RAFT experiments supported the feasibility of applying the method in outdoor cultivation. This study also investigated maximum biomass yields of nitrogen and phosphorus for producing S. obliquus biomass with indoor bench scale experiments. The results were tested in the outdoor raceways and demonstrated the potential of using fertilizer more efficiently in microalgae cultivation.

Doctor of Philosophy / Department of Animal Sciences and Industry / John M. Gonzalez / American beef producers use a multitude of production regimens, with new products constantly becoming available to producers that could ultimately produce beef that fits niche markets. Additionally, U.S. producers employ the use of two exogenous growth promotants (ExGP), anabolic implants and β-adrenergic agonists, to maximize production efficiency. This body of work examined effects of different production strategies on beef quality. In the first study, steers were fed a conventional diet or a diet containing two supplements of the Programmed Nutrition Beef Program (PN) and each diet was fed with or without ExGP. There were no adverse effects on color, but use of ExGP negatively impacted tenderness of steaks. However, the inclusion of the PN supplements decreased purge loss of loins during aging and decreased cook loss of beef steaks. The decrease in purge and cook loss may be intriguing for retailer who purchase-in and cook products as they could specify a demand for beef from animals in this program to potentially save on product losses. Researchers have examined strategies to increase omega-3 fatty acids within beef, as omega-3 fatty acids are health beneficial. The second study examined impacts of feeding increasing levels of a docosahexaenoic acid (DHA)-rich microalgae to heifers on fatty acid profiles, color stability, and palatability of the LM and color and . Feeding increasing levels of microalgae meal quadratically increased total omega-3 PUFA, with increases in DHA content up to 850% and eicosapentaenoic acid (EPA) up to 340% at the greatest feeding level. Although feeding microalgae changed fatty acid profiles to be more health beneficial, color and flavor were adversely affected. At the end of display, steaks from heifers fed the greatest amount of microalgae had reduced a* (redness) values and increases in surface metmyoglobin (discoloration) formation. Panelists detected more off-flavors as the level of microalgae meal increased in the diet. Poor color stability and increases in off-flavors were due to increased oxidation products in these steaks, but problems could be mitigated by inclusion of antioxidants in the diet. The third study presented examined effects of feeding antioxidants to steers fed microalgae meal on color and palatability of Longissimus lumborum steaks. Steers were fed vitamin E at a level over their nutritional need and a selenium-yeast product in addition to feeding microalgae. Again, feeding microalgae without antioxidants in the diet negatively impacted color during display, but feeding antioxidants significantly improved the color stability. There were no off-flavor differences between steaks from steers fed the diet containing only microalgae and diet containing microalgae with antioxidants. Increasing the antioxidant content of the finishing diet when microalgae was fed is feasible way to increase the color stability of steaks and decrease off-flavors of Longissimus lumborum steaks.

Master of Science / Department of Biological & Agricultural Engineering / Lisa R. Wilken / Microalgae has potential as a biofuel feedstock and as a source of valuable bioproducts for a variety of food, feed, nutraceutical, and pharmaceutical industries. However, several challenges are associated with bioproduct extraction from microalgae. The complexity of microalgae cell necessitates use of energy intensive disruption methods but current chemical or mechanical techniques can degrade economically valuable bioproducts. Aqueous enzymatic extraction (AEE), is a non-solvent and environmentally friendly bio-product recovery method that provides an opportunity to design an integrated process for protein and oil fractionation while reducing industrial costs. Based on the mechanistic understanding of biomolecule distribution and compartmentation, an aqueous enzymatic treatment for the release of internally stored proteins and lipid bodies in wild type Chlamydomonas reinhardtii was developed. In this study, we optimized harvesting times that maximized lipid and protein yields in nitrogen depleted cultures of the microalgae Chlamydomonas reinhardtii. Furthermore, an aqueous enzymatic extraction (AEE) treatment was developed. First, four lytic enzymes were tested for their ability to permeate C. reinhardtii cell walls. After cells were permeable, another set of enzymes were tested for their ability to release internally stored bioproducts. Protein recovery and lipid characterization after enzymatic treatment indicated a 54% release of total soluble protein and a localization of lipids to the chloroplast. Additionally, the development of secondary enzyme treatment for chloroplast disruption achieved about 70% total lipids released into the supernatant. Taken together, results indicate the application of an enzymatic treatment scheme for protein and oil recovery as a promising alternative to traditional extraction processes.

Background and Aim: Microalgae are a potential economical source of omega-3 fatty acids, which are known for their health benefits. Omega-3 fatty acids derived from microalgae are however still expensive due to high costs involved in production. These costs can partly be attributed to cultivation of microalgae in unialgal cultures, which are prone to contamination, difficult to scale up and require stringent control of growth conditions. This study therefore is aimed to investigate the feasibility of using a mixed microalgae culture for the production of omega-3 fatty acids. Methods and materials: The microalgae were grown under uncontrolled conditions in a hanging-bag photo-bioreactor, with only the phosphorus-nitrogen ratio (P:N-ratio) varied. Variations in the different population proportions in the culture were studied and related to the biomass, total fatty acid and omega-3 fatty acid productivity of the culture. Finally, a comparison was made between the results obtained in this study and similar studies found in literature. Results and discussion: The mixed culture used was composed of several green microalgae, whose proportions varied with P:N-ratio, season, and age of the culture. Different interactions between the populations were observable, and these were thought to influence the culture’s biomass, total fatty acids (TFAs) and omega-3 fatty acid productivity. The TFA content of the culture was ~10-20% by the end of the exponential phase, depending on the nutrients supplied. The fatty acids were composed of mostly unsaturated fatty acids, the majority of which were omega-3 fatty acids; C18:3ω3 (up to 50% of TFA), C16:4ω3 (up to 15%) and C18:4ω3 (up to 5%). Other fatty acids observed included C16:0 (up to 25%), C18:1ω9/C18:1ω8 (up to 20%), C18:2ω6 (up to 5%), traces of C18:0, C18:3ω6, C17:0, C16:3ω3 and C16:1ω7 were also detected. The presence of these fatty acids was found to vary depending on season, P:N-ratio, and age of the culture. When compared to studies in the literature, the mixed culture was found to perform better than, or as well as reported studies, where unialgal cultures were cultivated under controlled laboratory conditions. Conclusion: In view of the reported advantages of cultivating mixed cultures, the production of omega-3 fatty acids via such cultures appears attractive. More research however is needed to optimise the culture; study interactions between the organisms and their effect on biomass, total fatty acid and omega-3 fatty acid productivity. Finally, the economic implications of using mixed cultures need to be evaluated as well.

The ecologist Garrett Hardin (1968) introduced a useful concept called the tragedy of the commons, which describes how ecological resources become threatened or lost. The term “commons” is based on the commons of old English villages and is symbolic of a resource that is shared by a group of people. If every person were to use each resource in a sustainable fashion it would be available in perpetuity. However, if people use more than their share they would only increase their personal wealth to the detriment of others. In addition, an increase in the population would mean that the size of each share would have to decrease to accommodate the larger number of people. As a result, resources are threatened by personal greed and uncontrolled population growth. Freshwater is an example of a common resource that is under threat in South Africa where the average annual rainfall is less than 60 percent of the global average (Mukheibir & Sparks 2006). The increasing demands for freshwater as well as its eutrophication are major concerns with regards to estuarine health, environmental resource management and human health. The correct management of water is necessary to ensure that it is utilised in a sustainable manner. The National Water Act (No. 36 of 1998) has provided the rights to water for basic human needs and for sustainable ecological function; the Basic Human Needs Reserve and Ecological Reserve are both provided as a right in law. The amount of water necessary for an estuary to retain an acceptable ecological status, known as the Estuarine Ecological Reserve, is determined through the implementation of procedures (rapid, intermediate or comprehensive) compiled by the Department of Water Affairs and Forestry (1999) in its Resource Directed Measures (RDM) for the Protection of Water Resources. The impact of restricted flow on estuaries can be reduced by manipulating the water released from impoundments, the regulation of water abstractions within the river catchment or both (Hirji et al. 2002). The reserve assessment method is designed to evaluate ecosystem requirements by employing groups of specialists from different disciplines. In South Africa, this includes hydrologists, sedimentologists, water chemists and biologists (including microalgae specialists). The use of microalgae in ecological assessments has largely been based on research that was initiated at the Nelson Mandela Metropolitan University (formerly University of Port Elizabeth) and subsequently at Rhodes University (Grahamstown) and the University of KwaZulu Natal (Durban). The microalgal research can be divided into two main focus areas; phytoplankton and benthic microalgae

The release of water effluents rich in nutrients such as nitrogen and phosphorus without adequate treatment represents environmental and human health concerns. Growing concerns about these impacts have resulted in increasingly stringent water quality regulations that encouraged the adoption of advanced treatment processes. Microalgae-based advanced wastewater treatment has gained momentum owing to its well-known advantages for advanced wastewater treatment, including the recovering of nutrients for the production of fertilizers, biofuels and fine chemical from microalgal biomass. Nevertheless, the progressive membrane fouling and permeate flux declining hamper the large-scale commercialization of membrane photobioreactors (MPBRs) in the wastewater sector. In order to get a further understanding of the fouling mechanisms and antifouling control strategies, this study investigated the effect of the hydraulic retention time on the fouling development, and the effect of different physical fouling control strategies in the fouling mitigation. A synthetic secondary effluent was continuously fed to three MPBRs operated at different HRTs (12, 24 and 36 hours). Different fouling behaviors were found as the HRT changed, which was confirmed by continuously monitoring the transmembrane pressure (TMP) and by measurements in the biomass and its algal organic matter (AOM) properties. Lowering the HRT resulted in higher fouling rates due to changes in the biomass and AOM properties. Higher HRTs led to lower fouling rates and to a lower organic rejection across the membrane. The retention of small-MW organics in SMPBR12h was found to exacerbate the fouling resistance, whereas the accumulation of large-MW biopolymers enhanced the rejection of organics, despite of not imparting significant resistance in SMPBR24h. In order to assess the impact of different physical fouling control strategies, namely relaxation, backwash and air scouring, OCT in-situ monitoring was employed in MPBR12h to provide real-time information of the fouling layer properties (thickness and relative roughness) and its interaction with the membrane surface. Different fouling mechanisms were observed under different fouling control strategies. MPBRRLX and MPBRBW presented similar fouling rates despite of the lower permeate productivities of the latter. The lowest fouling rates were observed in MPBRSC, where stronger interactions between the membrane and small-MW organics and particles was observed.

The sunray venus (SRV) clam (Macrocallista nimbosa), is an alternative shellfish aquaculture species to hard clams (Mercenaria mercenaria) for Florida. Production of high-quality hatchery seed is dependent on diet. This study was initiated to determine an optimal live microalgae diet and test the efficacy of commercially available microalgae concentrates as partial or complete replacements for live algae. Benefits were seen with multiple algal species combinations. Both clam species achieved highest growth and survival when fed a multi-species quad-algal live diet, although hard clams performed well when fed I. galbana and C. gracilis or I. galbana and P. lutheri. Neither species performed well with complete replacement diets, but showed good production with partial replacement diets. The fatty acid (FA) profile of clams reflected the FA profile of the fed diet. Clams fed multi-species diets of live algae had a well-balanced FA profile consisting of high n3/n6, EPA/DHA and EPA/ARA ratios. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

Among various sources for biofuels, microalgae provide at least three-orders-of-magnitude higher production rate of biodiesel at a given land area than conventional crop-based methods. However, microalgal biodiesel still suffers from significantly lower harvesting efficiency, making such a fuel less competitive. To increase the separation efficiency of microalgae from cultivation solution, an orbital microchannel was utilized that enabled the isolation of biofuel-algae particles from the effluent. The results obtained showed that the separation efficiency in the microfluidic centrifugal separator can be as high as 76% within a quick separation time of 30 seconds. Multiple parameters of algae behaviors and separation techniques such as initial concentration, pH and temperature were studied and manipulated to achieve better efficiencies. It was found that changing these factors altered the separation efficiency by increasing or decreasing flocculation, or “clumping” of the microalgae within the microchannels. The results suggested that an acidic condition would enhance the separation efficiency since in a basic environment, large flocs of microalgae would block and hinder the separation process. Furthermore, a hot temperature solution (around 33 °C) yielded to a higher separation efficiency. The important characteristics of the separator geometry and the infusion rate on algae separation were also very effective in the separation process. This study revealed that there is an opportunity to improve the currently low efficiency of algae separation in centrifugal systems using much smaller designs in size, ensuring a much more efficient algae harvesting. / Includes bibliography. / Thesis (MS)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

Microalgae invite the attention of scientists due to their unique properties, including their quick growth, accumulation of lipids and other valuable substances, fixation of carbon dioxide and treatment of wastewater. This master´s thesis is focused on the study of microalgae. The main goal is to understand and describe the process of microalgae cultivation, in order to optimize it. The theoretical part of this thesis deals with microalgae (mainly Chlorella sp.) characterization, its practical use and cultivation optimization in order to obtain the highest concentration of biomass. The experimental part is divided into three tasks. Aim of the first task was the comparison of the course of autotrophic and heterotrophic cultivation of various strains of Chlorella and Coccomyxa microalgae, using three different cultivation media – synthetic medium for chlorella cultivation and natural fertilizer, Florium, used in two different concentrations (diluted 50 and 20 times). The highest Chlorella sp. biomass concentration of 7,10 g/l was achieved in the synthetic heterotrophic medium. Second task was focused on monitoring of the growth of algae Coccomyxa and Chlorella strain C1A, with respect to temperature and light intensity, using various combinations of these two important growth factors. Chlorella achieved its highest concentration of 11,46 g/l when grown at temperature of 33,5 °C and light intensity of 320 µE.m2.s1. The third and final task was to observe the growth of Dictiosphaerium chlerelloides microalgae on a flat cascade bioreactor. The experiment led to the discovery that these algae were able to grow at temperatures of around 10 °C, at which many well-known commercial algae, such as Chlorella sp. or Arthrospina sp., simply wouldn’t grow.