Valorization of marine fish waste biomass and Gallus gallus eggshells as feedstock and catalyst for biodiesel production

Fish and poultry processing industries generate vast quantities of by-products as wastes, creating disposal and environmental
problems. However, these wastes are an excellent source of oil and calcium-based catalyst. Against these concerns, the present
study primarily focuses on exploiting waste Gallus gallus chicken eggshell-derived CaO as a heterogeneous base catalyst for
biodiesel production from marine fish waste oil (MFWO). The oil yield of 95.2 wt% was obtained from marine fish waste by
the wet reduction method. Physicochemical characteristics of the MFWO suggested the suitability for biodiesel production.
X-ray diffraction, Fourier transform infrared spectra (FTIR), scanning electron microscopy, and Brunauer–Emmett–Teller
analysis of catalyst prepared from chicken eggshells by calcination at 900 °C for 4 h revealed that catalyst was crystalline and
mesoporous with the surface area of 6.058 m 2 g −1 . The biodiesel production from MFWO using calcined eggshell catalyst
was optimized by adopting a response surface methodology based on a central composite design. The maximum biodiesel
yield (86.5 wt%) was obtained with methanol-to-oil molar ratio of 25:1, catalyst dosage of 5 wt% of oil, reaction temperature
of 57 °C, and reaction time of 107 min. Thinlayer chromatography, FTIR, and gas chromatography analysis confirmed the
conversion of MFWO to biodiesel. The acid value (0.5 mg KOH/g), iodine value (131 g I 2 /100), flash point (115 °C), smoke
point (20 mm), and dynamic viscosity (5.88 cP) of MFWO biodiesel ensured its feasibility. These findings proposed that
exploiting MFWO and chicken eggshells for biodiesel production could reduce environmental pollution and disposal issues.