Lipase-catalyzed synthesis of biodiesel from black soldier fly (Hermetica illucens): Optimization by using response surface methodology

Abstract

Black soldier fly larvae (BSFL), oleaginous insects, can assimilate several organic wastes for fat accumulation, thus serving as a promising feedstock for biodiesel production. In this study, the transesterification of BSFL fat and methanol was catalyzed using lipases to produce environmentally friendly biodiesel. Different commercial lipases were evaluated for their catalytic activity in the reaction. Among the examined biocatalysts, Novozym 435, an immobilized enzyme, showed the highest activity level. Response surface methodology was subsequently used to optimize the lipase-catalyzed reaction and to develop a reliable empirical model for prediction. A maximum biodiesel yield of 96.18% was obtained at a temperature of 26°C, methanol:fat molar ratio of 6.33, enzyme loading of 20%, and reaction time of 9.48h. Under the optimal reaction conditions and enzyme regeneration process, Novozym 435 could be reused up until 20 times, yielding 92.5% biodiesel. The properties of BSFL biodiesel were also studied; all the properties met the standard EN 14214. This study suggests that the lipase-catalyzed conversion of BSFL fat to biodiesel is a promising method toward producing a green alternative fuel.