Exploring the potential of grease from yellow mealworm beetle (Tenebrio molitor) as a novel biodiesel feedstock

Biodiesel has been considered as one of the promising non-fossil fuels, but its development also have promoted a drastic debate due to its current production status, such as oilseeds dependency, arable land requirement, high cost and long-term impact on food prices. Therefore alternative resources with considerable lower cost that could be used for biodiesel production have been studied. Immature life stage of some insects is able to consume various organic wastes for fat accumulation. This high fat containing insect has the potential to serve as biodiesel feedstock. In this study, larval grease extracted from yellow mealworm beetle (Tenebrio molitor L.) (YMB), a post-harvest scavenger, was investigated for finding its potential as a substitute of oilseeds. Decayed vegetables were used to feed YMB and after 9 weeks, then the grease was extracted for biodiesel production. About 34.2 g biodiesel was obtained from 234.8 g dried YMB larval biomass. The main fatty acids of YMB biodiesel were linolenic acid (19.7%), palmitic acid (17.6%), linoleic acid (16.3%) and stearic acid (11.4%). Most of the properties of the YMB biodiesel fed on decayed vegetables met the standard EN 14214, including ester content (96.8%), density (860 kg/m3), flash point (127 °C), cetane number (58), water content (300 mg/kg), and methanol content (0.2%). From comprehensive analysis on the effect to society, economy and environment, it can be concluded that YMB can recycle organic wastes into clean energy with low cost.