Application of the Hydrodeoxygenation of Black Soldier Fly Larvae Lipids in Green Diesel Production

Abstract

To produce green diesel from black soldier fly larvae (BSFL; Hermetia illucens), the maximization of lipids in production and hydrodeoxygenation (HDO) reactions was investigated. In this study, BSFL were fed 12 diets based on three different substrates (ground corn, food waste, and meat by-product). The proximate compositions of larvae were analyzed, and rearing time, production rate, and feeding mixture prices were also recorded. To maximize the lipid yield, the effects of growing temperature, drying method, and extraction temperature were investigated. The HDO reaction of BSFL oil with 1 wt % Pt/Al2O3 catalyst was carried out in a trickle bed reactor. The components of the lipids produced under optimal conditions and the components of lipids produced through the HDO reaction were compositionally analyzed. As a result of being fed ground corn, food waste, and meat by-products, it was confirmed that the diet with 30% ground corn and 70% meat by-product led to the highest lipid content in the BSFL. After considering the prices of the diets, we found that the most ideal feeding conditions that could be applied to actual insect farming were 70% food waste and 30% meat by-products. From the perspective of the rearing period, the most appropriate BSFL-rearing temperature was a medium temperature of 38 °C. After harvesting the BSFL, it was confirmed that the lipid yield improved when extracted at a temperature of 65–75 °C after drying using a microwave. The analysis results showed that the carbon distribution in hydrodeoxygenated BSFL oil offered an advantage when used as drop-in fuel, and this represents a promising future step for the HDO of BSFL lipids.