Biodiesel Production from Fish Waste of <i>Ctenopharyngodon idella</i> (Grass fish), <i>Oreochromis niloticus</i> (Tilapia) and <i>Sardina pilchardus</i> (Sardine)

Numerous tons of fish waste are annually produced by fish processing facilities, leading to significant environmental issues related to emissions and degradation. Nonetheless, a viable solution exists in the conversion of these wastes into valuable resources such as biofuels, pharmaceutical ingredients, fertilizers, and animal feed. Among various waste sources, fish waste emerges as an optimal raw material for the production of biodiesel. In this research, fish waste from three distinct species viz., Ctenopharyngodon idella (grass fish), Oreochromis niloticus (tilapia), and Sardina pilchardus (sardine), were utilized as substrates. The wet extraction method yielded 92.15% FW oil. Physicochemical analysis revealed 3.487 cm-1 free fatty acids and an acid value of 7,291 cm-1 in FW oil. Post crossesterification, the free fatty acid content reduced from 2.543 mg/KOH/Kg to 0.944 mg/KOH/Kg, while the acid value dropped from 6.452 mg/KOH/Kg to 0.839 mg/KOH/Kg in biodiesel production. Spectral analysis (FTIR) identified a prominent peak indicating the presence of a methyl group (CH3) or methylene group in both crude FW and biodiesel samples. The moisture content of FW crude oil (0.69%) and biodiesel (0.00%) confirmed the absence of water post cross-esterification process completion. Ultimately, transesterification of FW crude oil utilizing a heterogeneous catalyst derived from fish waste is deemed an economically efficient approach for biodiesel manufacturing purposes.