Development of technological alternatives to produce renewable fuels from oleaginous microorganisms

  • Author / Creator
    Espinosa Gonzalez, Maria I
  • Microbial lipids are a promising feedstock for the production of renewable fuels. However, use of microbial lipids has been hindered due to challenges in the cultivating and processing of microbes. Thus, innovative technologies are required to enhance the feasibility of integrating oleaginous microorganisms into biofuel production strategies. Development of such technologies is the primary goal of this thesis. Slurries of oleaginous microbial biomasses (microalgae Chlorella protothecoides and yeast Cryptococcus curvatus) were thermally hydrolyzed under subcritical conditions. Hydrolysis products including fatty acids, aqueous byproduct streams, and insolubles, were separated and characterized. Fatty acids were subsequently pyrolyzed to yield renewable fuels. Microalgae and yeast were also cultured in aqueous byproduct streams from the hydrothermal processing of fats, oils, and oleaginous biomasses. Both model microorganisms used the glycerol byproduct from hydrolysis of fats and oils as a carbon source and displayed growth and lipid accumulation comparable to or better than cultures grown in pure glycerol. Similarly, supplementation of microbial cultures with microbial aqueous byproduct streams promoted higher biomass production compared to non-supplemented cultures. Finally, microalgae was grown using whey permeate, a byproduct from the cheese industry. Pre-hydrolyzed whey promoted heterotrophic growth of this microalgae in both batch and fed-batch modes. Furthermore, whey permeate could be consumed by microalgae using simultaneous saccharification and fermentation. The technologies for producing and using oleaginous biomasses proposed in this research reduce processing steps and valorize industrial waste streams. They also generate a suitable feedstock for renewable fuel production and a nutrient-rich supplement for microbial cultivation.

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  • Degree
    Doctor of Philosophy
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    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.