Hermetia illucens Larvae as a Living Bioreactor for Simultaneous Food by‐Products Recycling and Useful Oil Production

• Published in: Journal of the American Oil Chemists' Society 2020-07, Vol.97 (7), p.717-727
• Main Authors: Guil‐Guerrero, José L., Sánchez‐Muros, María J., Fabrikov, Dmitri, Rodríguez‐Lozano, Borja, González‐Fernández, María J., Lyashenko, Svetlana, Barroso, Fernando G.
• Format: Article
• Language: English
• Subjects: Biodiesel; Fatty acid methyl esters; Fruit by‐products; Functional oils; Hermetia illucens larvae; Lauric acid; Pork viscera
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1002/aocs.12370

The effects of feeds containing several food by‐products on the fatty acid compositions of Hermetia illucens larvae were studied. Coconut, tomato, apple, and viscera by‐products, as well as combinations of control feed containing carbohydrate‐rich additives were assayed. Final live weight (mg) and daily growth coefficient (%/day) ranged from 41 and 0.548 (tomato) to 93 and 1.292 (coconut), respectively. Oils containing lauric acid were obtained from larvae‐fed vegetable by‐products, especially those fed feed containing apple, coconut, and tomato (65.3, 54.4 and 52.3% of total fatty acids, respectively). Feed containing apple and a 1:1 (w/w) mix of control feed and apple by‐products yielded the highest proportion of fatty acids in the larvae (23.5 and 15.6 g fatty acids/100 g fresh larvae, respectively). The properties of biodiesel that could be produced from larvae fatty acids were calculated and the following values were obtained: cetane number (58.5–60.2), higher heating value (38.3–39.0 MJ·kg−1), density (0.869–0.873 g·cm−3), and induction period, an index of oxidation stability (8.4–150 hours). Such values were within the ranges specified by the ASTM D6751 and Europe EN 14214:2008 standards, while values for cold filter plugging point (−9.6 to 2.8 °C) were adequate for biodiesels intended for use in temperate climates. However, values for kinematic viscosity (2.93–3.58 mm2·s−1) were slightly below the requirements of EN 14214:2008 (3.5–5.0). Overall, larvae fed food by‐products produced lauric acid‐rich oils, and the calculated properties of the oils were largely suitable for biodiesel production.