Optimization of ultrasound-assisted oil extraction from Canarium odontophyllum kernel as a novel biodiesel feedstock

Abstract

In this novel study, oil was extracted from the kernel of an exotic indigenous species known as Canarium odontophyllum via an ultrasound-assisted process. The extraction process was optimized using response surface methodology (RSM) based on the Box-Behnken experimental design (BBD). The optimal conditions for the investigated parameters were determined as ultrasound amplitude level: 38.30%, ratio of n-hexane to kernel powder: 50:1 in mL/g, extraction time: 45.79 min, resulting in an oil extraction yield of 63.48%. For verification purposes, experiments were conducted using the same optimized values of the investigated parameters which resulted in the average oil yield of 63.27% and this prove the reliability of the regression model. The extracted oil’s fatty acid composition was obtained using a gas chromatograph (GC) equipped with flame-ionization detection (FID). The low acid value of the extracted oil is another interesting finding. This is important because it circumvents pretreatment processes such as degumming and esterification prior to the transesterification process. Biodiesel was produced from the oil via ultrasound-assisted transesterification, with a yield of 95.2%. Physiochemical properties of the C. odontophyllum biodiesel were determined, and it was found that all the tested properties comply with fuel specifications based on ASTM D6751 and EN 14214 standards. Significant savings of 52.3% and 80.9% in energy consumption and extraction time, respectively were achieved via ultrasound-assisted extraction compared with the conventional Soxhlet extraction. This study establishes the foundation and the need to further explore the usage of C. odontophyllum as a potential feedstock for biodiesel production.