Tefera, Nurelegne (PhD)Gebeyehu, Menelik2018-07-162023-11-102018-07-162023-11-102010-07http://etd.aau.edu.et/handle/12345678/8588Since petroleum resources are believed to last only for a few decades, alternative sources of biofuel production should be exploited. In order to replace all the fossil fuels consumed in the world, other sources of biodiesel which have higher productivity per unit area of land than vegetable and non edible oilseed feed stocks are required. One of the alternative sources which falls in to relatively higher productivity per unit area of land (10g/m2/day -50g/m2/day) is the production of biodiesel from microalgae. This study focuses on production of biodiesel from microalgae by transesterification reaction. Algal biomass of symbiotic blue green algae were collected from ARARI. After drying the biomass, algae oil was extracted by soxhlet extraction method using solvent, hexane. Then, purification of the oil was performed by degumming, neutralization, and bleaching to facilitate the characterization and biodiesel production process. The characterization test of the oil confirmed that oil can be produced from the algal biomass with the acceptable range of pyiscochemical properties for biodiesel production. Then, biodiesel was produced by base catalyzed transesterification reaction and characterized by determining density, kinematic viscosity, acid value, saponification number, flash point and heating value. HPLC analysis was conducted to determine the conversion of oil to biodiesel. The characteristic test result of the biodiesel showed that the density, kinematic viscosity, acid value, saponification number, flash point and heating value conforms to all the standard specifications of ASTM D 6751 and EN 14214, except for its acid value (0.57mgKOH/g) which is 14 % above the EN 14214 specification. The result showed that the symbiotic blue green algae in ARARI can be used to produce biodiesel with acceptable quality. However, the oil yield of the algal biomass was very low (5.4wt %) when compared with oil contents of algal strains (>15wt %) recommended for biodiesel production. Therefore, three different pure algal strains were selected and assessed based on their oil content and productivity with growth parameter requirements of climatic conditions which conform to the Ethiopian environment particularly to the specific area selected for cultivation. The results of the investigation showed that the strain Bortyococcus braunii gives the best result and recommended for cultivation of algal biomass for biodiesel production in Ethiopia.enProcess EngineeringThesis