Biodiesel from black soldier fly larvae grown on restaurant kitchen waste

Abstract

Biodiesel from insect larvae is an alternative to plant biodiesel, which have issues of using edible plants. On the contrary, insects can grow on waste. Although the conversion of larval lipids to biodiesel is known, characterisation of larval biodiesel is rarely reported. Here, black soldier fly larvae were cultivated for 20 days on kitchen waste. Larval lipids were extracted and converted to biodiesel by two-step transesterification. Analysis by optical polarisation microscopy from − 5 to + 15 °C showed tiny needle-like shaped crystals. Fourier transform infrared spectra of black soldier fly biodiesel revealed absorption bands at 1459 and 1435 cm⁻¹ corresponding to methyl ester, the main functional group of biodiesel. Nuclear magnetic resonance (NMR) analysis confirmed the presence of methyl ester by showing peaks at 3.6 and 2.3 ppm by ¹H NMR, and at 176 and 51.56 ppm by ¹³C NMR. Overall, our results confirm the successful conversion of black soldier fly larval lipid to biodiesel. This biodiesel met the American Society for Test and Materials D6751 and European Standard 14214.