No description available.

Thesis (M. Sc.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on Jan. 22, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Process Control, Department of Chemical and Materials Engineering, University of Alberta. Includes bibliographical references.

The enormous biodiversity of microalgae as well as their high photosynthetic rates can be exploited for a wide variety of applications including the production of high value chemicals, nutraceuticals, aquaculture feed, and most recently, biofuels. Regardless of the application, the productivity of the microalgae culture must be optimized in order to make the systems economically feasible. One environmental factor that greatly affects the productivity of mass cultivation systems is temperature since it can be prohibitively expensive to control in outdoor systems. Temperature affects microalgae growth rates both directly by its effect on metabolic rates, and indirectly, by changing the bioavailability of the inorganic carbon present in solution. In the first part of this research, the effects of dissolved inorganic carbon (DIC) concentration (varied by sparging CO₂-enriched air) and temperature on the growth of a model microalga species (Nannochloris sp., UTEX LB1999) were investigated in a turbidostat bioreactor. The results indicate that increasing DIC concentration yields higher microalgae growth rates up to an optimum value (around 3 mM for Nannochloris sp.) but higher concentrations actually inhibited growth. Since increasing the temperature decreases the DIC concentration for a given gas pCO₂, it is necessary to adjust the pCO₂ to maintain the target DIC concentration in the optimal range for growth. In the next phase of the research, the effect of average light intensity (Gav) and temperature on the growth rate of two microalgae species (Nannochloris sp., UTEX1999. and Phaeodactylum tricornutum, UTEX646) was investigated. Growth rates were measured over a range of average light intensities and temperatures using a turbidostat bioreactor. A multiplicative model was developed to describe growth as a function of both average light intensity and temperature. In the third phase of this research, both microalgae species were grown together to explore the effects of temperature fluctuations on the population dynamics of the co-culture. It was observed that Nannochloris was inhibited by the presence of P. tricornutum in the medium, probably due to the excretion of secondary metabolites into the medium that affected Nannochloris growth (allelopathic effects). The temperature and average light intensity model developed under monoculture conditions was modified to incorporate the allelopathic effects observed. The resulting model provided a reasonable fit to the dynamic behavior of a Nannochloris/P. tricornutum co-culture subjected to temperature variations in chemostat experiments. / text

published_or_final_version / Botany / Master / Master of Philosophy

No description available.

No description available.

Environmental awareness has increased significantly during the past years and the need to replace fossil fuels with a more sustainable alternative has become a priority in the modern society. Algal biofuels have shown to have a good productivity compared to other biomass feedstock options but the high cost- low-efficiency cultivation process has proven to be a challenge. The purpose of this project is to use membrane technologies to recover algal biomass more efficiently. This technology would significantly reduce the water usage and energy input to the algal biomass production process. In this study, the Derjaguin-Landau-Verwey-Overbeek (DLVO) model derived using the Surface Element Integration (SEI) technique was used to identify the interaction energy between 3 microalgae species and 5 hollow fiber membrane materials. The results suggested that Scendesmus Obliquous would have the lowest energy barrier (-2.7834 kT) with a Poly(vinylbutyral) (PVB) hollow fiber membrane, therefore it would have a greater initial number of algal cells attaching to the membrane, compared to the other microalgae and membrane materials studied. Further work needs to be completed in order to integrate algae growth and biomass harvesting into the actual model.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Also available online.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 182-196).