The determination of residual fiber composition from agricultural by-products after being treated with solid-state fermentation and black soldier fly larvae rearing

Several agricultural by-products such as cacao pod husk (CPH) and oil palm frond (OPF) are under-utilized by humans. Therefore, this study aimed to evaluate the fiber composition of CPH and OPF after being treated by solid-state fermentation (SFF) and black soldier fly larvae (BSFL) rearing. Several fungi species, of Phanerocheate chrysosporium (PC), Trametes versicolor (TV), and Pleurotus sajor-caju (PS), were used for SSF treatments, and they were inactivated using an oven at 60℃ for 24 h. Furthermore, the BSFL was grown on these SSF-treated substrates for 4-5 weeks, and the fiber composition was analyzed using the van Soest procedure. The results showed that the combination of SSF and BSFL rearing decreased and increased lignin in CPH and OPF, respectively. The combination of CPH-PC and BSFL rearing used almost all fiber fractions except hemicellulose. Meanwhile, the combination of unfermented OPF and BSFL rearing decreased only hemicellulose content. In conclusion, fungal fermentation of CPH and OPF enhanced the efficiency of nutrient utilization for BSFL growth and the change of their leftover substrate fiber composition.