Optimisation of biodiesel production of Black Soldier Fly larvae rearing on restaurant kitchen waste

Abstract

The objective of the study was to optimise the biodiesel production of Black Soldier Fly Larvae (BSFL) rearing on restaurant kitchen waste (RKW). The BSFL was inoculated into the RKW and left for 20 days. After that, the BSFL were harvested, rinsed, inactivated and oven-dried. The extraction of larval crude oil from BSFL was conducted using Soxhlet method with several solvents, namely petroleum ether, acetone and ethanol. Petroleum ether and reaction time of 6 hours were the best extraction conditions to produce larval crude oil production of up to 56 %. Then it was underwent two-step transesterification process to produce biodiesel. There are four experimental variables which were optimised using the Response Surface Methodology (RSM) based on central composite design. A quadratic model was employed to predict the biodiesel yield, where the R2 value was found to be 0.99 that reveal the satisfactory accuracy of the model to fit the experimental data. Based on optimisation studies, the optimum experimental conditions to obtain up to 96% of biodiesel from BSF larval oil were methanol:oil molar ratio of 9:1, catalyst concentration of 1 weight %, reaction time of 68 minutes and temperature of 60 °C.