Extraction of Intracellular Lipid as Potential Biofuel Source From Algal Biomass
Fossil fuels occuring as ancient algal deposit is the major source of energy for our engines today. It is a limited non-renewable resource that will eventually run out. It is in this regards that this work was carried out to determine and extract intracellular lipid in algal biomass for subsequent use as biofuel. Four average sized ponds within Federal University Dutse Campus, Nigeria (11.00̊ N to 13.00̊ N and longitude 8.00̊ E to 10.15̊ E and altitude 465.5m). were randomly selected and 20ml pond water were collected from top, middle and bottom of each pond. 60ml pond water was taken to laboratory and were processed by preparing the media. 3ml NPK gel fertilizer was mixed with distilled water and autoclave at 121°C for 15 min. Bold's Basal Medium (BBM) consisting stock solution and BBM consisting of trace elements were separately mixed with distilled water. 10 ml of the stock solution and 1.0 ml of the trace elements were autoclave at 121°C for 15 min. The media (BBM and fertilizer) were cooled at room temperature, antibiotics (penicillin G, di-hydro-streptomycin sulfate and gentamycin sulfate) were added and pH adjusted to 7.5 and the media were kept ready for used. Isolations of species were carried out by serial dilution using BBM and under microscope sterile syringe and needles were used to isolate target cells. Four different algal species; Euglena, Spirogyra, Selenastrum and Chlorella were isolated and identified. Culturing was carried out by transferring isolate into 50 ml growth chamber containing BBM and NPK fertilizer media separately and cultured using sunlight for 10 days under controlled pH. Two successfully grown species; Spirogyra and Selenastrum were transferred aseptically into four constructed photobioreactors containing 400 ml liquid media; two containing BBM and the other fertilizer media. Nile Red was used to stain the algal biomass, observed under microscope and photographed. Residual salts were removed and mass dried using thermostatic drying oven and subsequently grinded. Growths were determined through dry weight determination and growth percentage was obtained. The dried algal biomass was extracted and evaporated and extracts were heated using vacuum rotary evaporator to separate the solvent from the extracts. Transesterification was carried out. Phase separation was carried out along with purification in which soap and other impurities were removed and resulting solution remained flammable biodiesel. While Euglena and Chlorella failed to grow in the initial media, both Spirogyra, and Selenastrum produced significant amount of biodiesel with Selenastrum species producing higher quantity than that obtained from Spirogyra, hence a potential source of the fuel.