Integrating metabolomics and physicochemical analysis in black soldier fly bioconversion of Schizochytrium residue: A pathway to high-value ω-3 products

The global microalgae processing industry generates substantial residues rich in ω-3 fatty acids, presenting both a waste management challenge and an untapped resource for innovative food biotechnology. This study investigated the potential of bioconversion of Schizochytrium residue (SCR) by black soldier fly larvae (BSFL) to enrich ω-3 fatty acids and evaluated the industrial applicability of the resulting BSFL products. SCR supplementation enhanced larval growth performance (7.5 % increased weight, 19.9 % higher bioconversion rate) and protein quality, while enabling exclusive accumulation of EPA and DHA in BSFL. The total ω-3 content increased from 1.18 % to 17.37 %, achieving a nutritionally favorable n-6/n-3 ratio of 0.62 (the recommended ratio for human health <5). Metabolomics revealed that SCR upregulated TCA cycle intermediates and CoA biosynthesis, promoting FA synthesis, but NADPH limitations inhibited endogenous ω-3 elongation, suggesting direct assimilation of dietary PUFAs rather than de novo synthesis. Physicochemical analyses revealed improved thermal stability and β'-crystal formation in SCR-derived lipids. This work establishes a sustainable, technology-driven strategy for valorizing algal waste into nutritionally enhanced food ingredients, bridging the gap between circular bioeconomy principles and next-generation food production.