Optimization of Solvent Extraction of Spotted Melon (Lagenaria breviflora) Seed Oil: A Feedstock for Green Fuel in Nigeria

The provision of affordable and clean energy, SDG 7 is one of the seventeen sustainable development goals, which is paramount in most countries in Africa such as Nigeria because it plays a vital role in socio-economic development. The use of waste materials and non-edible underutilized seed oil such as spotted melon (Lagenaria breviflora) will help minimize these challenges. Hence, the need to extract the oil from this non-edible seed. The extraction efficiency of n-hexane, is dependent on factors such as the particle size of solute material, extraction time, etc. This study is aimed at evaluating the operating variables that would give an optimum yield of Lagenaria breviflora seed oil (LbSO) and to study the effect of the interaction of these factors. A central composite design (CCD) response surface methodology (RSM) was used for the optimization study while statistical analysis using analysis of variance (ANOVA) was used to test the significance of the variables for the process. The variables considered for this study were temperature (^oC), sample weight (g), and extraction time (min.). The physical and chemical properties of the extracted LbSO were determined using standard methods which included the Scanning Electron Micrograph (SEM) and Energy Dispersive X-ray Fluorescence (EDXRF). The RSM analyses results showed that the three variables have a significant effect (p 0.05) on the yield of LbSO, with R² = 0.9725 and Adj. R² = 0.9477 which showed a good fitness of a second (quadratic) order model. Based on this model, optimal operating variables investigated for the extraction process were established as temperature 63.92 ^oC, sample weight 60.14 g and extraction time of 3.39 hrs, which gave a yield of 22.80% LbSO. The Physico-chemical properties of the extracted LbSO showed that it is a suitable raw material for industrial purposes such production of biodiesel, bio-lubricant, soaps, glycerol, detergents, etc. The EDXRF analysis of the LbSO extracted meal revealed the presence of SiO₂ (27.23%), K₂O (24.11%), CaO (3.46%), and Al₂O₃ (3.93 %,) which can be enhanced for the production of heterogeneous catalyst for the production of biodiesel.