selection of cell disruption technique, organic solvent and transesterification catalyst Nattapon Sumprasit creator Annachhatre, Ajit P. Chairperson Visvanathan, C. Examination Committee Shipin, Oleg V. Examination Committee Thailand (HM Queen) Scholarship Donor text series technical report th Pathum Thani, Thailand Asian Institute of Technology 2016 continuing eng 76 p. : ill. + 1 online resource The main objective of this research was to optimize biodiesel production from ubiquitous Spirulina platensis microalga including selection of appropriate cell disruption technique, selection of appropriate solvent for highest lipid recovery yield, and selection of appropriate catalyst for transesterification reaction. Cell disruption process for lipid extraction of S. platensis was initially investigated with seven different techniques. According to results of lipid recovery yield and energy balance analysis, osmotic shock was the most suitable cell disruption technique which recorded 8.87% of lipid recovery yield. Subsequently, seventeen organic solvents were investigated through three-stage lipid extraction in which 5:1 v/w of solvent to biomass ratio was used during each stage. Highest lipid recovery yield was obtained from chloroform/methanol 1:2. Lastly, transesterification reaction was carried out by using methanol as medium. Three types of catalyst were used in the reaction namely alkali catalyst, acid catalyst, and combination of acid and alkali catalyst. Due to high free fatty acid content in lipid of S. platensis (42.04%), acid catalyst recorded better biodiesel yield as compared to alkali catalyst. Sulfuric acid as acid catalyst gave the highest biodiesel conversion yield of 79.45%. Accordingly, the recommended process for production of biodiesel from S. platensis includes following steps: cell disruption through osmotic shock followed by lipid extraction by chloroform/methanol 1:2, and finally conversion into biodiesel using sulfuric acid as the catalyst for transesterification. Under these condition, biodiesel yield of 7.06% (based on weight of biomass) was obtained with net energy balance gain 14.03 MJ/kg of biodiesel. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Engineering and Management Thesis (M.Eng.) - Asian Institute of Technology, 2016 Biodiesel fuels Biomass energy Biodiesel fuels By-products Organic solvents Spirulina Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B02634 http://203.159.5.9/ait-thesis/detail.php?q=B02634 190402 20260817171430.0