A strategy for high-yield lauric acid production in Hermetia illucens fed with pre-fermented sweet potato-based substrate

The intensification of animal farming is associated with increased infectious and zoonotic disease risks. The black soldier fly larvae (BSFL) have antimicrobial activity that could potentially be used to suppress diseases and improve animal health. This study used carbohydrate-rich sweet potato and lauric acid-rich desiccated coconut to differentiate the primary source of lauric acid. The study also investigated the effect of pre-fermenting the substrates with Bacillus sp. and Klebsiella sp. on the BSFL growth performance and fatty acid composition, particularly on lauric acid. Correlation analyses were conducted between the larvae fed with fresh substrate and fermented substrate. Overall, the sweet potato enhanced the lauric acid biosynthesis, and the fermented sweet potato-based substrate resulted in a remarkable lauric acid production of 82%, i.e., 365 mg g⁻¹ in the BSFL biomass. Pre-fermentation aided production of precursors like oleic acid, linoleic acid, and glycolysis of readily available carbohydrates, which spiked the lauric acid biosynthesis.