Cultivation, extraction and optimization of biodiesel production from potential microalgae Euglena sanguinea using eco-friendly natural catalyst

Algal biofuels have caught worldwide attention, due to the success of first and second generation biofuels on combing environmental concerns in spite of many challenges. Microalgae are the potential and sustainable fuel source with carbon neutrality, where selection of promising strain is crucial for effective biofuel generation. Euglena sanguinea one such robust freshwater species with high lipid productivity was explored on laboratory scale as well as in mass scale in raceway pond. The extracted oil's fatty acid value was only 3.8 mg KOH g−1 and had 93% triglycerides. Acid value was reduced to ∼0.3 mg KOH g−1 by esterification and the optimized parameters obtained were: methanol/oil ratio: 0.36, H2SO4: 10 vol.%, time: 42 min. In the subsequent transesterification process natural, recoverable and eco-friendly white mussel shell was used. Maximum yield of ∼98% was obtained at 6 wt.% of calcinated CaO for the reaction time of 80 min at 0.35 methanol/oil ratio. The GC-MS analysis of the algal biodiesel showed the presence of saturated fatty acids: C16:0, C18:0, C22:0, C24:0 and monounsaturated fatty acids C18:1 at appropriate level to provide better oxidation stability and combustion properties to use it for automotive application without any major engine modifications.