Vincent, Omega Anthony2019-07-042020-01-072019-07-042020-01-072011Vincent, O. A. (2011) Production of biofuels from tropical seaweeds, Master dissertation, University of Dar es Salaam. Available at (http://41.86.178.3/internetserver3.1.2/detail.aspx)http://localhost:8080/xmlui/handle/123456789/1353Available in print formToday, the worldwide transport sector is almost entirely dependent on petroleum-based fuels. Fuel resources of fossil origin are exhaustible and nonrenewable. The spiraling prices and increasing concern over greenhouse gas (GHG) emissions inflicted by their use have led to an increased global interest in alternative fuels. One major problem with biofuel production is the choice of a technically feasible, economically competitive, environmentally acceptable, and readily available feedstock. This study discusses the fuel potential of some selected seaweeds namely; Ulva lactuca, Ulva reticulata, Eucheuma dentiulatum, Kappaphycus alvarezii, Padina gymnospora and Hydrocrathratus crathrus. The extraction of oils and biofuels was carried out using different technologies under mild energetic conditions. n-Hexane and ethyl acetate (3:1) were used in a Soxhlet to extract lipids from seaweed powders while methanol and NaOH were used in transesterification of these lipids into biodiesel. The mean percentage yields of biodiesel were significantly different among seaweed species (P < 0.05), but were generally very low (<3% of their dry weight) in all species. The mean percentage yields of bioethanol, produced through fermentation of seaweed powders using Saccharomyces cerevissiae, ranged from 4.72% to 26.15% of their dry weight. The quantity of bioethanol produced varied significantly among species (P < 0.05). Determination of heat content for both bioethanol and seaweed pellets was done using standard test method ASTM D 3172-5. For bioethanol, the values ranged from 29600 kJ/kg to 30000 kJ/kg with no significant variation among the species (P > 0.05). For pellets, the values ranged from 8.278 MJ/kg to 16.893 MJ/kg and statistically varied significantly (P < 0.05). These findings suggest that seaweed have very low amounts of lipids to warranty production of biodiesel through transesterification at a commercial scale. However, some seaweed species such as Ulva lactuca and Eucheuma denticulatum can further be researched as they have shown potential in producing bioethanol.enbiofuelstropical seaweedsThesis