Fatty acid ethyl ester from Manilkara zapota seed oil: A completely renewable biofuel for sustainable development

Abstract This article reports the deliverables of the experimental study on the production of a completely renewable biofuel from Manilkara zapota fruit. It was attempted to produce fatty acid ethyl ester from Manilkara zapota seed oil using bioethanol synthesized from decayed Manilkara zapota fruit. Bioethanol was produced through fermentation of decayed Manilkara zapota fruit, waste skin, and pulp with Saccharomyces cerevisiae then extracted by distillation process at the temperature of 72°C. The bioethanol yield was noted as 10.45% (v/w). The purity of the bio-ethanol was identified as 95.09% using infrared spectroscopy and gas chromatography-mass spectrometry. Mechanically extracted Manilkara zapota seed oil was used for ethyl ester production. The molar ratio of bioethanol to oil, the quantity of KOH, and process temperature were optimized for the maximum yield of Manilkara zapota ethyl ester. 9:1 molar ratio of bioethanol to oil, 1.5% (w/w) KOH, and 70°C process temperature were identified as optimized ethanolysis process parameters. The maximum yield of ethyl ester was identified as 93.1%. Physicochemical characteristics of Manilkara zapota oil, bioethanol, and ethyl ester were measured as per the corresponding ASTM standards. It was found that both Manilkara Zapota ethyl ester and bioethanol synthesized from decayed Manilkara zapota fruit could be promising substitutes for fossil diesel and gasoline.