Determining of local algal genera for production of omega-3 fatty acids.

Abstract

Essential fatty acids are lipids that cannot be synthesized by our bodies and must be consumed through a diet or supplements. Omega-3 fatty acids are key for life and are currently obtained from seafood or dietary means. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the most biologically active omega-3 fatty acids. Although these sources of omega-3 fatty acids are available, the world still faces challenges such as high land area for cultivation. Microalgae are a worldwide concern as they pose a promising renewable and sustainable energy source and have the ability to produce high volume of fats/lipids rich in the omega-3 fatty acids. The objectives of the study were to (i) identify the most promising genus of algae for cultivation based on their fatty acid composition, ease of cultivation and economic feasibility, (ii) to identify the genera of algae native to the region that have high levels of omega-3 fatty acids, (iii) to extract and quantify the oil from algae and determine the optimal conditions for the cultivation of each algae genus including temperature, pH and salinity. Algae samples were collected from Lubigi swamp. Samples from water were obtained using plastic disposable glasses and covered and then labelled. Genera identification for each collected sample using isolation techniques such as streak plating and microscopy was done. Different media that is Bold’s Basal media and a random plant fertilizer was used for cultivation and propagation of algae to determine the best way to culture the algae that can be adapted by the locals. No growth was seen in the local plant fertilizer as the algae was seen decomposing. Faster growth was seen in sample C as strong green color was observed. Oil was extracted out of the two algal genera biomass using Bligh and Dyer method giving a volume of 5ml and 6ml from sample A1 and sample C respectively. The fatty acid composition of the extracted oil was determined using gas chromatography coupled to a mass spectrophotometer by transesterification of the oil to form methyl esters. Both samples contained a higher composition of saturated fatty acids. Lastly both oil samples did not contain omega-3 fatty acids therefore the need to explore other culturing techniques, larger volumes and better extraction methods are recommended.