| dc.description.abstract | Microalgae they have the ability to produce substantial amounts (- 20-50% dry cell weight) of triacylglycerols (TAG) as a storage lipid under photo-oxidative stress or other adverse environmental conditions. Microalgal community composition of three Kenyan Rift Valley lakes Turkana, Magadi and Baringo was composed of 100 microalgae species belonging to six phyla of microalgae. Lake Turkana had the highest micro algae species composition of 73, the common species were Chlorella spp, Anabaena spp and Microcystis spp while Lake Baringo had a total of 37 species, Anldstrodesmus spp, Euglena spp and Scenedesmus spp were most common. Lake Magadi recorded a total of 57 microalgae species and Nitzschia spp was the most common species. The species richness and diversity were highest in L. Turkana and consistently lower in L. Baringo. Classification and nMDS ordination also revealed significant dissimilarity in phytoplankton community structure between the three lakes.
Lake Turkana amongst the lakes had the highest nutrients levels revealing its eutrophic nature. Chlorella spp, Scenedesmus spp, Anldstrodesmus spp, Euglena spp and Nitzschia spp were isolated and cultured in Bold Basal Medium (BBM). Microalgae biomass was harvested by centrifugation after every 21 days and lipids extracted by the Bligh and Dyer method. Chlorella species showed the highest yields (10.5%) followed by Euglena acus (5.78%), Nitzschia (3.68%), Anldstrodesmus falcatus (1.58%) and Scenedesmus acuminatus (1.58%). Gas chromatography analysis revealed the profile of the algal community.Chlorella spp, Euglena spp and Anldstrodesmus spp had similar fatty acid composition but differed in concentrations. Cytochrome c oxidase 1 gene for Chlorella spp, Scenedesmus spp and Nitzschia spp was amplified and sequenced. phylogenetic analyses by MEGA 4 indicated that Nitzschia spp and Chlorella spp are different evolutionally, Scenedesmus spp and Chlorella spp both being of the same phyla show great similarity with a 71 % score compared to the Nitzschia spp which is a diatom. From this research it can be concluded that Chlorella spp is potential source of biofuel. | en_US |
