Sustainable Bioenergy: Biodiesel Production From Microalgae Occurring In Ghana

ABSTRACT Due to increasing oil prices and climate change concerns, biodiesel has gained attention as an alternative energy source. Biodiesel derived from microalgae is a potentially renewable and carbon–neutral alternative to petroleum fuels. This study was carried out to determine the potentials of producing biodiesel from microalgae obtained from freshwater bodies in Ghana to serve as an environmentally sustainable fuel and an alternative to the use of fossil diesel. In the study, water samples with algal blooms were collected from the Weija reservoir, wastewater ponds in and near University of Ghana, main campus, Prampram and a freshwater pond at Teshie in Accra. Based on their morphology and ease of cultivation, four (4) microalgae were isolated and identified as Oedogonium sp., Chroococcus sp., Spirogyra sp. and Closterium sp. These isolates were : (i) cultured in a 2 litre reagent bottle Photobioreactor (improvised) using sunlight as the energy source, (ii) harvested by filtration to reduce their water content and centrifuged into pastes, (iii) dried and ground into powder to extract algal oil and (iv) the algae oils were transesterified into biodiesel. Results indicated a significant growth in terms of percentage dry weight in Oedogonium sp. (55.8%) and a lower dry weight of 40.1% in Closterium sp., with Chroococcus sp. and Spirogyra sp. ranging between 50.2 and 50.0 % respectively. Results also indicated that under room temperature, air, natural source of light and appropriate medium these species can grow profusely. Significant amounts (20- 38%) of microalgal oil were efficiently extracted with hexane and diethyl ether and transmuted into biodiesel. Closterium sp. yielded very significant amount of biodiesel of 94 %, while a yield of 80% was produced from Chroococcus sp. The percentage yield for Oedogonium sp. was 49% and the least percentage biodiesel yield was 33% for Spirogyra sp. This work was able to isolate and identify four freshwater microalgae which are rarely used in research works for biodiesel production. In producing biodiesel, it can be concluded that, Oedogonium sp., Closterium sp., Spirogyra sp. and Chroococcus sp. are viable species which can provide substantial amount of algal oil for biodiesel production. Hence, investments must be made to develop a better and economically viable technology for large scale cultivation of algae for the production of biodiesel in Ghana. Also an in-depth economic analysis should be performed on each aspect of the algae to biodiesel production process. This can reduce the cost of producing biodiesel, and ultimately making it a better alternative to fossil diesel in Ghana