Variables Affecting the In-Situ Transesterification Via Ultrasonic from Microalgae and Comparing with Other Methods of Transesterification

The aim of this study is to investigate the variables affecting the in-situ transesterification via ultrasonic bath for Spirulina platensis microalgae species. The optimum conditions were the presence of co-solvent to algae oil mass ratio 3:1 v/w, catalyst percentage 100% to the oil weight and molar ratio of alcohol to algae oil mass 30:1 which gives 70% yield at room temperature for 30 minute. Scendismus species was subjected to one step transesterification via ultrasonic bath under the optimum conditions of Spirulina platensis and recorded 76% yield of fatty acid methyl ester. Chlorella species obtained from Alexandria University through MED algae project was subjected to two step transesterification via ultrasonic bath under the previous optimum conditions. Comparison between different methods of transesterification (extraction followed by transesterification process, direct transesterification process and direct transesterification via ultrasonic bath) was studied. The extraction and transesterification process resulted in higher ester yield than direct transesterification process either via ultrasonic bath or without. The GC analysis of crude biodiesel from Spirulina platensis, Scendismus species and Chlorella species showed that they are promising algal species for biodiesel production with high oxidation stability and high predicted cetane number due to high percentage of saturated fatty acid methyl ester (SFAME).