Direct conversion of yellow mealworm larvae into biodiesel via a non-catalytic transesterification platform

Abstract

A massive quantity of organic waste is generated globally. Despite its detrimental impacts on all environmental media (soil, water, and air), a sustainable valorization platform for organic waste has not been fully developed. In an effort to reduce the technical gap, this study placed great emphasis on a new valorization route employing the conversion of food/agricultural waste to biodiesel (BD). In this study, the yellow mealworm larvae (MW) were grown on piles of wheat bran to convert carbohydrates to fat through its fast metabolism. The ultimate aim was to enhance the economic viability of BD by producing fat from food/agricultural waste. Fat from MW larvae were then converted to BD through the non-catalytic conversion (authors-invented) process. As a reference, conventional acid/base-catalyzed transesterification of fat from MW larvae was also made. The conventional conversion process revealed a BD yield of 48.55 wt%, which was attributed to the high content of moisture and impurities in the MW extract. The non-catalytic conversion process of MW extract showed a BD yield of 87.75 wt% in 1 min at 370 °C, showing an extraordinarily high tolerance against water and impurities. The non-catalytic reaction also allowed the in-situ conversion of fat in MW to BD even at 320 °C without fat extraction. The enhanced reaction kinetics could be due to the catalytic effects of the alkaline earth metals in MW.