An assay based on Nile red fluorescence was developed for quantitative analysis of triglycerides, a common cellular component with important biological functions and is routinely analyzed for diagnosis of metabolic disorders and as an important feedstock of food industry and biodiesel production. Based on studies on the Nile red fluorescence of pure, binary, and ternary systems of triglycerides, ethanol, and water, 20% ethanol aqueous solution was determined to be the most suitable solvent for lipid fluorescence measurement. Excellent linearity was established for lipid samples in the range of 0.1- 0.5 mg/ml with several different lipid standards and vegetable oils. Results also suggest that the fluorescence of triglycerides was not sensitive to the fatty acid composition of lipids. This finding is important since it implies that the assay could potentially be used for the measurement of triglyceride content of different oil crops without causing significant variations. The results of this method were then verified by comparing with the results of the conventional gravimetric methods. The results of the fluorescence assay were consistently lower than that of the gravimetric method by approximately 10%. This phenomenon was tentatively attributed to the fact that the gravimetric method measures the total amount of lipophilic materials in samples while the fluorescence assay is selective to glycerides. Attempts were also made to apply this assay to estimate the lipid content of green alga Neochloris oleoabundans. However, the results were less than ideal due to the existence of interfering components in the extract of microalga samples that could significantly repress the fluorescence of lipids.

Replacing fossil fuels with algae, a renewable resource, is an exciting possibility. This study evaluates the algae found in South Texas brackish water ponds used for aquaculture of fish as a possible source of biofuels. Samples of algae from these ponds were cultured at varying temperatures ranging from 15.5ºC to 36.5ºC. High levels of growth were observed at 20.5ºC and the highest lipid content was measured at 23.0ºC. Temperature was also a factor in the distribution of microalgal taxa throughout the temperature gradient. This information will be added to the growing body of research investigating similar cultures of algae for future biofuel production. / text

Algae are a promising new source of oil for biodiesel. They are aquatic organisms that do not require cropland, and they can produce many useful side-products for bioenergy, aquaculture, and nutraceutical production. To be cost-effective, algae need high and reliable oil productivities; however, there is still a great deal to learn about the effects of culturing conditions on algae growth rates and lipid production. These culturing conditions include light intensity, gas flow, use of CO₂, and culture volume. An extensive database of published research on algae growth rates and lipid contents under a wide variety of environmental conditions was prepared. By graphing data from 116 publications on 132 microalgae species, several key trends were identified relating to culturing parameters and algae biomass and lipid production. In addition, data from 131 publications on 128 microalgae species were graphed to look at presence of flagella, nutrient limitation, lipid productivity, and productivity tradeoffs. Moreover, cell size information was gathered for 146 species. The interactions between culture variables are complex, so it is difficult to quantify the degree to which each culture variable affects algae growth rates and lipid production. Therefore, several multivariate analyses were performed to generate a set of general and simple predictive models to assess specific growth rates, maximum lipid contents, and volumetric lipid productivities. These models were used to determine which culture parameters were significant predictors of algae growth rates and lipid production, and the contribution of each environmental parameter was quantified. In addition to models for algae in general, genera specific models were prepared for Chlorella, Isochrysis, Nannochloropsis, Phaeodactylum, and Tetraselmis. These models show high predictive capabilities, and they greatly extend the range of species-specific multiple regression models available. Furthermore, one Tetraselmis model was validated using Tetraselmis impellucida growth experiments in a large novel photobioreactor.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Made available in DSpace on 2016-06-02T19:22:53Z (GMT). No. of bitstreams: 1 3145.pdf: 4807955 bytes, checksum: e7ba1c165199af2b5606877c0fadf24b (MD5) Previous issue date: 2010-03-12 / Universidade Federal de Sao Carlos / The aim of the present study was to investigate the effects of resistance training on skeletal muscle lipid content, liver lipid content, heart lipid content, fat depots and lipid profile in ovariectomized rats. Wistar adult female rats were grouped into: sedentary (Sed-intact); ovariectomized sedentary (Sed-Ovx); strength trained (ChronicEx-intact) and ovariectomized strength trained (ChronicEx-Ovx) (n= 10 per group). A 12-week strength training period that consisted in climbing a 1.1-m vertical ladder with weights attached to rats tail was used. The sessions were performed once every 3 days with 4-9 climbs and 8-12 dynamic movements per climb. Ovariectomy increased liver lipid content, fat depots, heart and muscle lipid content. There was an increase in atherogenic index and negative change in lipid profile due to ovariectomy. Resistance training decreased lipid content in liver, soleus, tibialis anterior, fat depots (mesenteric and retroperitoneal) and lipid profile, independently of ovarian hormone status. These results indicate the potential benefits of resistance training as an alternative strategy to control the effects of ovariectomy on fat depot, lipid profile, and tissue lipid content. / O objetivo do estudo foi investigar os efeitos do treinamento de força sobre o conteúdo lipídico no músculo esquelético, fígado, coração, depósitos de gorduras e perfil lipídico em ratas ovariectomizadas. Ratas fêmeas adultas foram divididas em quarto grupos: Sedentário (Sed-Intacto); Sedentário ovariectomizado (Sed-Ovx); Treinado intacto (CrônicoEx-Intacto); Treinado ovariectomizado (CrônicoEx-Ovx) (n = 10 por grupo). Foi realizado um período de 12 semanas de treinamento de força que consistia em subidas de uma escada vertical de 1,1 metros, com peso atado no rabo. As sessões foram realizadas uma vez a cada três dias com 4- 9 subidas e 8-12 movimentos por subida. Foram analisados os conteúdos de lipídios no músculo esquelético, fígado, coração, depósitos de gorduras (urogenital, mesentérico e retroperitoneal) e perfil lipídico. Ovariectomia aumentou o conteúdo lipídico no fígado, músculos esqueléticos, coração e depósitos de gordura. Foi observado um aumento no índice aterogênico e mudanças negativas no perfil lipídico devido à ovariectomia. O treinamento de força diminuiu o conteúdo de lipídio hepático, nos músculos esqueléticos sóleo, tibial anterior, depósitos de gordura (mesentérico e retroperitoneal) e perfil lipídico independente do estado hormonal ovariano. Esses resultados indicam os benefícios potenciais do treinamento de força com uma estratégia alternativa para controlar os efeitos da ovariectomia sobre os depósitos de gordura, perfil lipídico e conteúdo tecidual de lipídio.